etudes
Well-known member
I am looking forward to catching up on this thread.. this weekend.
Pedalboard Reflections
- Thread starter bacchettadavid
- Start date
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bacchettadavid
Well-known member
I've been busy for the last few weeks, but I'll have time this weekend to revise the more recent posts and post the next section. Stay tuned.
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bacchettadavid
Well-known member
Some recent discussions with another UUer have inspired me to finally finish this thread....here we go...
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bacchettadavid
Well-known member
PART III continued
C. SIGNAL CHAIN
As we consider this conclusion to Part III, we would do well to observe a couple of disclaimers on pedal order:
C.1: General Guidelines
'Ukulele signal chains are structured to preserve "acoustic" qualities in the amplified tone. They prioritize a pristine, distortion-free signal (i.e., even when distortion is present, it is cleanly amplified). Let us begin by examining a common 'ukulele signal chain (NOTE: most chains will omit one or more components or combine several into a signal unit):
Fig. 1: Common Signal Chain
This section explores some signal chains that subvert the guidelines above.
Fig. 2: Compression near the end; reverb before delay
C.3: Special Considerations
COMBINED EFFECTS
Most 'ukulele signal chains feature components that combine several effects. The most common are pre-amp/corrective filtration/DI boxes. Many of these boxes feature additional effects such as compression and reverb. When compression is not included, it is probably best to place compression either before the pre-amp or, if an effects loop is provided, either very early or very late within the effects loop.
TRUE-BYPASS EFFECTS AND BUFFERS
Some effects units offer true-bypass functionality. These units minimize signal coloration by disconnecting the internal circuitry from the signal chain when inactive. While this can result in reduced tonal loss, it comes at the cost of an output buffer (many of which can adversely affect signal fidelity). For these reasons, true-bypass effects are common in 'ukulele signal chains.
In longer signal chains, the capacitance of the cables filters out high frequency content from the signal, resulting in a loss of presence, articulation, and brightness. The amount of signal loss varies with cable quality, but longer signal chains (especially those with several true-bypass effects in a row) will generally benefit from the use of a high-quality buffer early in the chain. Another common application for buffers is between a high-impedance output and a long unbalanced run of cable to an amp.
BYPASS LOOPERS AND EFFECTS LOOPS
As discussed above, some effects units can discolor the signal when disengaged. The easiest way to remove this discoloration is through the use of a bypass looper, which is essentially a switch that allows an effects unit to be further removed from the signal chain. Another use for bypass loopers is to create "patches" of multiple effects that can be turned on or off with the push of a single button.
Some units offer a feature known as an effects loop. These generally provide a high-quality buffered output called a "send" that can be connected to a secondary signal chain before returning to the unit via a "return" input. Effects loops allow for the inclusion of longer signal chains that can be easily disconnnected from the primary signal chain.
PREAMPS INTO ACOUSTIC COMBO AMPS
In some cases, it may be necessary to connect a preamp to an acoustic combo. Acoustic combos feature their own preamp sections, and stacking one preamp into another compounds noise and distorts the signal. This noise and distortion can usually be minimized by increasing the gain on the dedicated preamp and decreasing the gain on the combo preamp. Additionally, if the acoustic combo provides an effects loop, the combo's preamp can be bypassed by connecting the dedicated preamp can also be connected the combo's effects return line.
Neither solution is perfect. The former grants the player access to the combo's tone shaping controls but increases noise and distortion; the latter bypasses the entire input section of the combo and can affect the behavior of the combo's power amp and speaker.
As always, sound reinforcement is a compromise. Listen carefully and trust your ears as you experiment within your options.
C. SIGNAL CHAIN
As we consider this conclusion to Part III, we would do well to observe a couple of disclaimers on pedal order:
- Objective physical ramifications exist for the order of any given signal chain; however, the aesthetic value of these ramifications is often subjective.
- Every finger, string, instrument, pickup element, cable, amplifier, speaker, ear, etc. is unique; even seemingly identical electronic components vary.
C.1: General Guidelines
'Ukulele signal chains are structured to preserve "acoustic" qualities in the amplified tone. They prioritize a pristine, distortion-free signal (i.e., even when distortion is present, it is cleanly amplified). Let us begin by examining a common 'ukulele signal chain (NOTE: most chains will omit one or more components or combine several into a signal unit):
Fig. 1: Common Signal Chain
- instrument -> pre-amplification -> tuner -> compression -> filtration (wah, fuzz, and pitch shifters) -> volume (excluding tremolo) -> drive (overdrive, distortion) -> modulation (phaser, flanger, chorus) -> volume (including tremolo) -> time-based effects (delay, reverb, looper) -> amplification -> driver
- 1. Pre-amp first. See Part I.
- 2. Tuner as early as possible. Tuners work best when presented with the cleanest (least affected) signal possible. This placement also ensures that the built-in mute feature does not mute impede active time-based effects and that the built-in buffer helps preserve brightness early in the chain.
- 3. Compression before filtration. Filtering a compressed signal allows for the frequencies boosted by the compressor to be subject to the filter. Compressing a filtered signal tends to affect timbre.
- 4. Filters before drive. Corrective filtration, such as EQ, is generally best placed before overdrive or distortion is applied to the signal chain. Wah placed before drive both increases timbral range of drives and minimizes perceived volume changes during Q sweeps. Most forms of pitch shifting track best when placed before any disruption to the signal's harmonic structure.
- 5. Drive pedals in increasing order of signal disruption. Drives stacked in this manner provide increasingly coarse stages of tonal grit. This order also minimizes the hyperaccentuation of feedback-inducing harmonics.
- 6. Modulation in increasing order of time delay, with level modulation placed last. A phased signal running through a chorus has more apparent definition than a chorused signal being phased.
- 7. Time-based effects in increasing length of tail. 'Ukulele players generally use these pedals to thicken their tone slightly or to create the auditory illusion of space. In physical spaces, echoes are generally subject to reverberation. By placing the looper at the end of the chain, the player is able to independently shape each dub stored in the looper.
This section explores some signal chains that subvert the guidelines above.
Fig. 2: Compression near the end; reverb before delay
- instrument -> drive -> modulation -> reverb -> compression -> delay
Compression is used lightly squash is the changes in volume induced by many modulation and reverberation effects. Note that compression is not applied to trailing off of the delay tails.
- instrument -> pre-amplification -> reverb -> delay -> drive
Delay and reverb become more present and splashy when placed before a drive. The drive becomes more dynamic as it is hit by the time-based effects tails.
- instrument -> pre-amplification -> chorus -> delay -> tremolo -> reverb
A mild chorus and a long delay with many repeats is "chopped up" by a tremolo. A medium reverb is used to round out the overall sound.
- instrument -> compression -> distortion -> wah -> volume -> reverb
A wah is used to sweep the Q band through a distorted waveform. This minimizes the wah's timbral range whilst increasing its volume sweep.
C.3: Special Considerations
COMBINED EFFECTS
Most 'ukulele signal chains feature components that combine several effects. The most common are pre-amp/corrective filtration/DI boxes. Many of these boxes feature additional effects such as compression and reverb. When compression is not included, it is probably best to place compression either before the pre-amp or, if an effects loop is provided, either very early or very late within the effects loop.
TRUE-BYPASS EFFECTS AND BUFFERS
Some effects units offer true-bypass functionality. These units minimize signal coloration by disconnecting the internal circuitry from the signal chain when inactive. While this can result in reduced tonal loss, it comes at the cost of an output buffer (many of which can adversely affect signal fidelity). For these reasons, true-bypass effects are common in 'ukulele signal chains.
In longer signal chains, the capacitance of the cables filters out high frequency content from the signal, resulting in a loss of presence, articulation, and brightness. The amount of signal loss varies with cable quality, but longer signal chains (especially those with several true-bypass effects in a row) will generally benefit from the use of a high-quality buffer early in the chain. Another common application for buffers is between a high-impedance output and a long unbalanced run of cable to an amp.
BYPASS LOOPERS AND EFFECTS LOOPS
As discussed above, some effects units can discolor the signal when disengaged. The easiest way to remove this discoloration is through the use of a bypass looper, which is essentially a switch that allows an effects unit to be further removed from the signal chain. Another use for bypass loopers is to create "patches" of multiple effects that can be turned on or off with the push of a single button.
Some units offer a feature known as an effects loop. These generally provide a high-quality buffered output called a "send" that can be connected to a secondary signal chain before returning to the unit via a "return" input. Effects loops allow for the inclusion of longer signal chains that can be easily disconnnected from the primary signal chain.
PREAMPS INTO ACOUSTIC COMBO AMPS
In some cases, it may be necessary to connect a preamp to an acoustic combo. Acoustic combos feature their own preamp sections, and stacking one preamp into another compounds noise and distorts the signal. This noise and distortion can usually be minimized by increasing the gain on the dedicated preamp and decreasing the gain on the combo preamp. Additionally, if the acoustic combo provides an effects loop, the combo's preamp can be bypassed by connecting the dedicated preamp can also be connected the combo's effects return line.
Neither solution is perfect. The former grants the player access to the combo's tone shaping controls but increases noise and distortion; the latter bypasses the entire input section of the combo and can affect the behavior of the combo's power amp and speaker.
As always, sound reinforcement is a compromise. Listen carefully and trust your ears as you experiment within your options.
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etudes
Well-known member
I'm on board! Look forward to the discussion.
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bacchettadavid
Well-known member
Part III is finished. Part IV to follow soon.
Fascinating thread. A lot of terminology I am not familiar with I need to decipher.
Enjoying it a lot. Thanks for putting in all of this effort.
Enjoying it a lot. Thanks for putting in all of this effort.
cyber3d
Well-known member
Are you going to address single power supplies with multiple outlets? I just replaced my individual power supplies with one. 360 Looper, Superego+, Gamechanger Pedal Plus sustain pedal.
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bacchettadavid
Well-known member
I love your choice in effects, but you definitely has some slightly unusual power needs there.
I'll be focusing on a variety of power supply formats, but yes, I'll devote most of that section to power supplies with multiple isolated outlets.
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bacchettadavid
Well-known member
PART IV - Power Supplies and Pedalboard Layout
DISCLAIMER
This section pertains to the handling of electric current. Audio devices and cables are capable of carrying sufficient electrical current to damage or destroy equipment, cause fires, and injure or kill humans. This section does not serve as a comprehensive primer on power supplies and omits many concepts important to the safe manufacture, testing, setup, operation, and/or repair of effects pedals.
The poster of this thread, a.k.a. Bacchettadavid, accepts no responsibility for equipment damage, damage to property or persons caused by fire, or injury or death resulting from the setup, use, or takedown of audio or video equipment. Learn and adhere to the guidelines in device manuals and follow all applicable laws. Additionally, consult https://midimagic.sgc-hosting.com/indamage.htm and https://web.mit.edu/jhawk/tmp/p/EST016_Ground_Loops_handout.pdf for other important safety and device protection information.
A. INTRODUCTION TO POWER SUPPLIES
No effects unit ever sounds any better than its supply of power allows. Perhaps second only to the preamp/DI box, the power supply is the single most significant component of any pedalboard.
The primary function of a pedalboard power supply is to provide appropriate power whilst limiting extraneous noise. Effects units frequently exacerbate extraneous noise by either introducing noise or amplifying exisating noise, and the summative effect of all this noise can limit or defeat the utility of many amplified acoustic setups. Fortunately, several of these sources of noise (fluctuating or insufficient power, ground loops, and digital chatter) can be significantly reduced by the intelligent selection and application of a power supply.
A.1: Categories
Power supplies can be broadly divided into four categories:
Both linear and switch-mode supplies are available in a variety of formats. Some of the more popular formats include:
B. PEDAL POWER PARAMETERS
Power supply selection is dependent upon the power needs presented by a given effects chain. This section focuses on the different power demands presented by pedals.
B.1: Power Specifications of Pedals
Electron Flow
Most pedals expect DC though a few expect AC. As a general rule, AC pedals should recieve power from their own dedicated wall wart. Connecting a DC pedal to AC power can damage the pedal.
Polarity
DC power plugs exhibit polarity, and DC-powered pedals expect a specific polarity plug. Most pedals specify center-negative, but a few effects units use center-positive specifications. Center-positive polarity is generally employed in units with unique power requirements to prevent users from connecting center-positive units to a daisy chain. Connecting an effects unit to the incorrect polarity will cause a short, and the unit (as well as all other units sharing the same isolated output) will fail to work until the out-of-spec pedal is removed from the loop. In some cases, connecting a pedal without polarity protection to the incorrect polarity will result in damage to the pedal. Some germanium-based units are "ground-positive" and thus incompatible "ground-negative" effects units (i.e., almost all modern effects units) regardless of center polarity.
Voltage
Most pedals expect 9V, but specifications as high as 18V are common. As a general guideline, use only rated outlets with voltages matching the voltages of the devices being powered. Connecting a unit to higher voltage than that for which it is designed can damage the unit or diminish its lifespan. Under certain circumstances, it is possible to operate a unit below its specified voltage though this may change the unit's behavior.
Amperage
All pedals draw some amount of current, and this current draw is usually expressed in milliAmperes (mA). Published estimates of a unit's current draw are available either on the unit itself or within its associated manual. In many cases, published mA ratings for a given unit exceed the actual current draw, a practice which persists because some outputs do not provide as much current as indicated. When daisy chaining effects, the amperage sum of all devices within the daisy chain should not exceed the indicated rating of the outlet. In some cases, the outlet's current rating can be exceeded by as much as 20% without causing problems, but in other cases, this practice can lead to the build-up of heat within the power supply and cause power supply damage or even a fire.
B.2: Isolation
Isolation is not explicitly a power requirement and can be an especially thorny topic in the building of acoustic pedalboards, so I'm going to devote a little column space to a brief discussion on the topic.
Under certain conditons, pedals interact in ways that generate noise in the audio band when plugged into non-isolated outlets. Digital effects pedals in particular are notable for this behavior and frequently exhibit "chatter" when multiple digital pedals are powered from the same isolated power source. In many cases, this noise can be quieted by powering each of the offending pedals using a separately isolated outlet. As a general rule, analog pedals sharing the same outlet generate less noise than digital pedals would sharing that same outlet, and many analog pedals can share an isolated outlet with a digital pedal so long as they do not add too much gain. Sometimes, even multiple digital pedals can share the same outlet as long as they aren’t all simultaneously engaged.
What follows are a few guidlines for best practices when isolating pedals to minimize hum and chatter and thus lower the noise floor:
DISCLAIMER
This section pertains to the handling of electric current. Audio devices and cables are capable of carrying sufficient electrical current to damage or destroy equipment, cause fires, and injure or kill humans. This section does not serve as a comprehensive primer on power supplies and omits many concepts important to the safe manufacture, testing, setup, operation, and/or repair of effects pedals.
The poster of this thread, a.k.a. Bacchettadavid, accepts no responsibility for equipment damage, damage to property or persons caused by fire, or injury or death resulting from the setup, use, or takedown of audio or video equipment. Learn and adhere to the guidelines in device manuals and follow all applicable laws. Additionally, consult https://midimagic.sgc-hosting.com/indamage.htm and https://web.mit.edu/jhawk/tmp/p/EST016_Ground_Loops_handout.pdf for other important safety and device protection information.
A. INTRODUCTION TO POWER SUPPLIES
No effects unit ever sounds any better than its supply of power allows. Perhaps second only to the preamp/DI box, the power supply is the single most significant component of any pedalboard.
The primary function of a pedalboard power supply is to provide appropriate power whilst limiting extraneous noise. Effects units frequently exacerbate extraneous noise by either introducing noise or amplifying exisating noise, and the summative effect of all this noise can limit or defeat the utility of many amplified acoustic setups. Fortunately, several of these sources of noise (fluctuating or insufficient power, ground loops, and digital chatter) can be significantly reduced by the intelligent selection and application of a power supply.
A.1: Categories
Power supplies can be broadly divided into four categories:
- Batteries are the "cleanest" power source, and some high-gain effects benefit from their use. Unfortunately, this solution is expensive and environmentally harmful.
- Linear power supplies contain a step-down transformer to reduce voltage and a rectifier to convert from AC to DC. The larger ones sometimes contain a fan to help dissipate heat. While not generally travel-friendly (some countries prohibit their use due to their inefficiency), a few can be manually switched between between 120V and 230V mains operation. The transformers found in these devices can leak flux and induce noise in certain pedals if not properly shielded.
- Switch-mode power supplies contain a transistor switch which is rapidly (frequently at a frequency outside the audio band) switched between voltage and current states. These units are generally smaller and more efficient (and thus generate less heat) than equivalent linear power supplies, but they present non-trivial design problems. Even well-designed units can impart noise through high-gain effects, and filtering out this noise can impact tone. Switch-mode power supplies often exhibit greater flexibility in their outlet channel sections.
- Distributed power systems are frequently some combination of switch-mode and linear technology but modularized into separate units. These units can be combined into various configurations to meet myriad power requirements.
Any of these options can work (and some power supply solutions are a synthesis of multiple categories), but the diverse power requirements and minimal presence of high-gain effects on 'ukulele pedalboards make switch-based designs potentially more appealing.
Both linear and switch-mode supplies are available in a variety of formats. Some of the more popular formats include:
- Voltage-regulated wall warts: power adapters containing a plug that can be inserted into a power strip outlet. A wall wart can be used to power a single pedal or, through the use of a daisy chain (cable that can connects multiple pedals to one power output), multiple compatible pedals.
- Pedalboard power supply: a power brick (or combination of bricks) that mounts directly to a pedalboard. Many power supplies contain additional components such as regulators, multiple galvanically isolated outlet sections, dip switches to change the behavior of outlets, AC outlet sections, and switches to change between 120V and 230V mains operation. In some cases, these supplies are modularized into several smaller boxes, each with a specific purpose.
As with the categories above, some power supplies combine features of multiple form factors.
B. PEDAL POWER PARAMETERS
Power supply selection is dependent upon the power needs presented by a given effects chain. This section focuses on the different power demands presented by pedals.
B.1: Power Specifications of Pedals
Electron Flow
Most pedals expect DC though a few expect AC. As a general rule, AC pedals should recieve power from their own dedicated wall wart. Connecting a DC pedal to AC power can damage the pedal.
Polarity
DC power plugs exhibit polarity, and DC-powered pedals expect a specific polarity plug. Most pedals specify center-negative, but a few effects units use center-positive specifications. Center-positive polarity is generally employed in units with unique power requirements to prevent users from connecting center-positive units to a daisy chain. Connecting an effects unit to the incorrect polarity will cause a short, and the unit (as well as all other units sharing the same isolated output) will fail to work until the out-of-spec pedal is removed from the loop. In some cases, connecting a pedal without polarity protection to the incorrect polarity will result in damage to the pedal. Some germanium-based units are "ground-positive" and thus incompatible "ground-negative" effects units (i.e., almost all modern effects units) regardless of center polarity.
Voltage
Most pedals expect 9V, but specifications as high as 18V are common. As a general guideline, use only rated outlets with voltages matching the voltages of the devices being powered. Connecting a unit to higher voltage than that for which it is designed can damage the unit or diminish its lifespan. Under certain circumstances, it is possible to operate a unit below its specified voltage though this may change the unit's behavior.
Amperage
All pedals draw some amount of current, and this current draw is usually expressed in milliAmperes (mA). Published estimates of a unit's current draw are available either on the unit itself or within its associated manual. In many cases, published mA ratings for a given unit exceed the actual current draw, a practice which persists because some outputs do not provide as much current as indicated. When daisy chaining effects, the amperage sum of all devices within the daisy chain should not exceed the indicated rating of the outlet. In some cases, the outlet's current rating can be exceeded by as much as 20% without causing problems, but in other cases, this practice can lead to the build-up of heat within the power supply and cause power supply damage or even a fire.
B.2: Isolation
Isolation is not explicitly a power requirement and can be an especially thorny topic in the building of acoustic pedalboards, so I'm going to devote a little column space to a brief discussion on the topic.
Under certain conditons, pedals interact in ways that generate noise in the audio band when plugged into non-isolated outlets. Digital effects pedals in particular are notable for this behavior and frequently exhibit "chatter" when multiple digital pedals are powered from the same isolated power source. In many cases, this noise can be quieted by powering each of the offending pedals using a separately isolated outlet. As a general rule, analog pedals sharing the same outlet generate less noise than digital pedals would sharing that same outlet, and many analog pedals can share an isolated outlet with a digital pedal so long as they do not add too much gain. Sometimes, even multiple digital pedals can share the same outlet as long as they aren’t all simultaneously engaged.
What follows are a few guidlines for best practices when isolating pedals to minimize hum and chatter and thus lower the noise floor:
- DC pedals require DC outlets; AC pedals require AC outlets
- each digital unit should have its own dedicated isolated outlet
- pedals with unique voltages should be powered by voltage-regulated, isolated outlets with matching voltage ratings
- always-on pedals should be restricted to no more than 2 units per isolated outlet
- the combined current draw of any daisy-chained pedals should not exceed the indicated maximum current draw of their isolated outlet section
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bacchettadavid
Well-known member
The continuation of Part IV, which will focus on power supply selection and pedalboard layout, should be posted before the end of the weekend.
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bacchettadavid
Well-known member
Of course!!! If possible, accompany the picture with a brief diagram of your signal chain. You might also want to expand upon a couple of your favorite tones on the pedalboard to guide the rest of us.
I’ll be posting a picture of my current setup in the next major update.
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Brilliant thanks . not sure my set up would be classed as a pedalboard i bought a Tech21 FlyRig but it has a Compressor Delay & Reverb in the chain going into a Fishman Loudbox Mini , i'll sort a few photo's out . Cheers .
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bacchettadavid
Well-known member
PART IV continued
C. SELECTING A POWER SUPPLY
C.1: Charting Power Requirements
The first step in power supply selection is to track the power requirements of your effects units. Begin by referencing and recording the electron flow (AC/DC), polarity (+/-), voltage (9/12/15/18/24), and amperage (mA) requirements of every effects unit you intend to power. When recording amperage, note that the reported current draw is often inflated; also keep in mind that certain digital pedals consume far more power than indicated while booting up. For an easy way to improve the accuracy of your estimates of current draw, invest in a milliamp meter designed for testing pedals (a multimeter can perform a similar function but has a steeper learning curve). When you are satisfied that your figures are complete, be sure to sum all the amperages for an estimate of total current draw. You will also want to tally up the total number of digital vs analog units, list of voltages required (and their associated mA ratings), unique power requirements (center-positive, unusual jack size, always-on, etc.), &c. See list 1 for an example of my current pedalboard's power requirements:
List 1: Sample Power Requirements Outline
Charting Isolation Requirements
Once you have these figures recorded (I recommend a spreadsheet), you are ready estimate what minimum number of isolated outlets you might require. List 2 below is a generous isolation map of the pedals outlined in list 1. Note that this isolation map has been optimized to minimize hum and thus lower the noise floor as much as is reasonably practical:
List 2: Isolation map of pedals in list 1
Locating a Power supply
When you arrive at an estimate for your number of isolated outputs, the next step is to locate a power supply solution that meets those requirements. As you weight your options, consider the following primary concerns:
Once your needs are well-understood, it is time to scour the market for an appropriate power supply. I caution that designing audio-grade power supplies is non-trivial challenge, and you get what you pay for; Cioks, The GigRig, Strymon, Truetone, and Voodoo Lab all take quality power supplies to market.
Additionally, remember to ensure that the necessary connectors (jack sizes, polarity converters, voltage and current doublers, etc.) are available for any power supply you are considering. These topics are outside the scope of this post, but if you have a question, please ask it in the thread.
C.2: Power Supply FAQ
Do I really need a dedicated pedalboard power supply or will a wall wart suffice?
Given the significant cost difference between using multiple wall warts and investing in a dedicated power supply, a valid concern exists over whether a dedicated power supply might be needed.
If you don't require more than two (or possibly three) isolated outlet sections, wall warts (or other voltage-regulated adapters) plugged into the same power strip will likely suffice to meet your needs. This power strip can actually be mounted to the pedalboard but should always share the same safety ground as the rest of your sound reinforcement solution.
Once your isolation needs exceed 2 to 3 outlet sections, continuing to use wall warts unduly risks the formation of ground loops and other sources of noise. Additionally, the inconvenient negotiation of any more than 3 wall warts and the associated daisy chains poses a significant impediment.
Switch-mode power supplies from reputable designers are expensive. How do I know whether I need a switch-mode power supply?
Switch-mode power supplies are becoming increasingly prevalent as high-current digital effects units make their way onto more pedalboards. If many of your favorite effects requires comparatively high currents (150mA or greater), you should consider investing in a switch-mode power supply.
There isn't a power supply on the market that meets my exact needs. How shall I proceed?
You may need to supplement a pedalboard power supply for most of your effects units with a dedicated wall wart for an especially problematic device. Unfortunately, no single solution currently on the market will work for every person.
Should I just invest in a distributed power system instead of bothering with an integrated switch-mode power supply?
If you already own a linear pedalboard power supply that meets your current needs, you may want to consider skipping switch-mode power bricks entirely and moving directly into distributed power systems. This has the potential of being a cheaper, quieter, and more convenient option in the long run.
Well, that wraps up this discussion of power supplies. Part IV continues next with a discussion of best practices for pedalboard layout.
C. SELECTING A POWER SUPPLY
C.1: Charting Power Requirements
The first step in power supply selection is to track the power requirements of your effects units. Begin by referencing and recording the electron flow (AC/DC), polarity (+/-), voltage (9/12/15/18/24), and amperage (mA) requirements of every effects unit you intend to power. When recording amperage, note that the reported current draw is often inflated; also keep in mind that certain digital pedals consume far more power than indicated while booting up. For an easy way to improve the accuracy of your estimates of current draw, invest in a milliamp meter designed for testing pedals (a multimeter can perform a similar function but has a steeper learning curve). When you are satisfied that your figures are complete, be sure to sum all the amperages for an estimate of total current draw. You will also want to tally up the total number of digital vs analog units, list of voltages required (and their associated mA ratings), unique power requirements (center-positive, unusual jack size, always-on, etc.), &c. See list 1 for an example of my current pedalboard's power requirements:
List 1: Sample Power Requirements Outline
- Unit 1: analog, 15VDC @ 400mA, center-positive, cannot be disengaged.
- Unit 2:analog, 9VDC @ 50mA, always on but no output.
- Unit 3:analog, 9VDC @ 20mA, usually on, mid-gain.
- Unit 4:analog, 9VDC @ 30mA, cannot be disengaged, variable gain.
- Unit 5:analog, 9VDC @ 10mA, used only in conjunction with units 6 & 7.
- Unit 6:analog, 9VDC @ 20mA, battery power available, high gain & noisy.
- Unit 7:digital, 9VDC @ 180mA, used in conjunction with high gain effect.
- Unit 8:digital, 9VDC @ <100mA, always on.
- Unit 9:digital, 9VDC @ 65mA, always on.
- Unit 10:digital, 9VDC @ 350mA on startup and @ 200 mA thereafter, cannot be turned off.
- Total current draw of approx. 1.2A.
- 4 digital pedals, 3 always on, remaining pedal used in conjunction with high-gain analog effect.
- 1 pedal 15VDC @ 400mA and center-positive.
- 1 pedal 9VDC @ 180mA; 1 pedal 9VDC @ 350 mA max.
- 2 9VDC analog pedals functionally always on.
Charting Isolation Requirements
Once you have these figures recorded (I recommend a spreadsheet), you are ready estimate what minimum number of isolated outlets you might require. List 2 below is a generous isolation map of the pedals outlined in list 1. Note that this isolation map has been optimized to minimize hum and thus lower the noise floor as much as is reasonably practical:
List 2: Isolation map of pedals in list 1
- Isolate A: 15VDC @ 400mA, center-positive required, unit 1.
- Isolate B: 9VDC @ 350 mA, unit 10.
- Isolate C: 9VDC @ 180 mA, unit 7.
- Isolate D: 9VDC @ 70mA, units 2 & 3 daisy-chained.
- Isolate E: 9VDC @ 30mA, unit 4.
- Isolate F: 9VDC @ 30, units 5 & 6 daisy-chained.
- Isolate G: 9VDC @ <100mA, unit 8.
- Isolate H: 9VDC @ 65mA, always on.
Locating a Power supply
When you arrive at an estimate for your number of isolated outputs, the next step is to locate a power supply solution that meets those requirements. As you weight your options, consider the following primary concerns:
- total power output of your power solution should exceed the total consumption of your entire chain; this reserves some current for growth or changing out units
- AC/DC availability should meet the needs of your devices
- mA ratings for the various sections should be sufficient to power digital units
- Voltage options should meet or exceed your present needs
- number of isolated outputs should exceed your estimated minimum number by at least 1
Once your needs are well-understood, it is time to scour the market for an appropriate power supply. I caution that designing audio-grade power supplies is non-trivial challenge, and you get what you pay for; Cioks, The GigRig, Strymon, Truetone, and Voodoo Lab all take quality power supplies to market.
Additionally, remember to ensure that the necessary connectors (jack sizes, polarity converters, voltage and current doublers, etc.) are available for any power supply you are considering. These topics are outside the scope of this post, but if you have a question, please ask it in the thread.
C.2: Power Supply FAQ
Do I really need a dedicated pedalboard power supply or will a wall wart suffice?
Given the significant cost difference between using multiple wall warts and investing in a dedicated power supply, a valid concern exists over whether a dedicated power supply might be needed.
If you don't require more than two (or possibly three) isolated outlet sections, wall warts (or other voltage-regulated adapters) plugged into the same power strip will likely suffice to meet your needs. This power strip can actually be mounted to the pedalboard but should always share the same safety ground as the rest of your sound reinforcement solution.
Once your isolation needs exceed 2 to 3 outlet sections, continuing to use wall warts unduly risks the formation of ground loops and other sources of noise. Additionally, the inconvenient negotiation of any more than 3 wall warts and the associated daisy chains poses a significant impediment.
Switch-mode power supplies from reputable designers are expensive. How do I know whether I need a switch-mode power supply?
Switch-mode power supplies are becoming increasingly prevalent as high-current digital effects units make their way onto more pedalboards. If many of your favorite effects requires comparatively high currents (150mA or greater), you should consider investing in a switch-mode power supply.
There isn't a power supply on the market that meets my exact needs. How shall I proceed?
You may need to supplement a pedalboard power supply for most of your effects units with a dedicated wall wart for an especially problematic device. Unfortunately, no single solution currently on the market will work for every person.
Should I just invest in a distributed power system instead of bothering with an integrated switch-mode power supply?
If you already own a linear pedalboard power supply that meets your current needs, you may want to consider skipping switch-mode power bricks entirely and moving directly into distributed power systems. This has the potential of being a cheaper, quieter, and more convenient option in the long run.
Well, that wraps up this discussion of power supplies. Part IV continues next with a discussion of best practices for pedalboard layout.
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bacchettadavid
Well-known member
Brief teaser for the final section of Part IV:
Wow! Thanks again for doing all of this. Fantastic job.
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bacchettadavid
Well-known member
PART IV continued
D. PEDALBOARD LAYOUT
You have pedals and a board, and you’re ready to start thinking about how to lay everything out (and wire it up!).
The considerations outlined in this section are sequential, and players using this section to streamline their own pedal layout procedure would do well to observe how decisions made at each stage constrains later decisions.
At the end of this section, I’ll present a longform example by using diagrams to lay out my own pedalboard.
D.1: Overall Dimensions
Obviously, you need to keep in mind the overall dimensions of your selected pedalboard. You can mitigate the impact of dimensional restrictions by using a board that is large enough to hold 1-2 more pedals than you are currently incorporating, but this is often inadvisable due to space and weight concerns.
Notable features of the board’s overall dimensions include the following:
D.2: Inputs and Outputs
The first consideration should be the placement of any jacks where a signal either enters or exits the pedalboard. These jacks should be made readily accessible on the board’s outside perimeter(s).
What this means:
D.3: Large Pedal Placement
Large pedals (wah, expression, preamp/DI boxes, workstations, etc.) should be placed early during the layout planning cycle.
For the most ergonomic placement, rocker pedals should be placed in locations where they can be easily reached by the foot you use to modulate them. Many players forego ergonomics and instead opt for sonically intuitive placements (and possibly shorter patch cable runs); for example, they might place a volume pedal used as a clean boost or envelope filter to the right but a volume pedal used for swells and fades to the left.
The exact location of these units may not actually matter all that much if you don’t use them often and/or have an especially large pedal board.
D.4: Power Supply Placement
This section assumes you are using a power supply with isolated outputs.
The primary decision you face when placing a power supply is whether to mount the power supply above or below the pedal mounting surface. Mounting above gives you easy access to the power supply and simplifies the process of troubleshooting power issues whereas mounting below frees up additional space on the main board surface for additional units (note that you cannot mount units on the power supply itself since it needs to be able to shed heat).
Secondary considerations include leaving negative space for the placement of the power cord itself and assessing whether the power supply interacts with other circuits in a way that produces excessive noise. For example, some less-shielded power supplies induce noise in certain wah pedals; if this is the case in your chain, you may want to consider placing your power supply some place other than directly below a wah pedal.
The final part of placing a power supply is to ensure that you have adequate power cable lengths for each required connector type to adequately power all of your units; otherwise, you may be forced to omit or misplace certain pedals due to the limitations of your available power connectors. Some power supply manufacturers supply varying cable lengths for each connector type, so you can sometimes wait until after you’ve placed most of your pedals to finalize the placement of your power supply.
D.5: Prioritization and Ease-of-Reach
Now that you’ve made arrangements for your input and output sections, larger units, and power supply, you can begin arranging your remaining units.
For many players, this process is a balancing act between ergonomics (for physical ease of use), performer’s intuition (for seamless integration into performances), and signal routing complexity. Outlined below are a few general guidelines:
D.6: Cable Routing
Cable management is worth dipping your toes into once you’ve achieved a comfortable layout for your board. Well-managed cables can reduce noise and improve reliability of your board.
When routing cables, observe the following:
D. PEDALBOARD LAYOUT
You have pedals and a board, and you’re ready to start thinking about how to lay everything out (and wire it up!).
The considerations outlined in this section are sequential, and players using this section to streamline their own pedal layout procedure would do well to observe how decisions made at each stage constrains later decisions.
At the end of this section, I’ll present a longform example by using diagrams to lay out my own pedalboard.
D.1: Overall Dimensions
Obviously, you need to keep in mind the overall dimensions of your selected pedalboard. You can mitigate the impact of dimensional restrictions by using a board that is large enough to hold 1-2 more pedals than you are currently incorporating, but this is often inadvisable due to space and weight concerns.
Notable features of the board’s overall dimensions include the following:
- Number of rows of pedals possible given your most common enclosure size
- Ground clearance under the pedal mounting surface
- Presence of multiple tiers or hinged mounting surfaces
- Methods available to mount pedals (nylon ties, brackets, Velcro, etc.)
- If using a pedalboard case, the clearance between the mounting surfaces of the board and the interior dimensions of the case
D.2: Inputs and Outputs
The first consideration should be the placement of any jacks where a signal either enters or exits the pedalboard. These jacks should be made readily accessible on the board’s outside perimeter(s).
What this means:
- The first pedal in your signal chain benefits from placement along the righthand or topmost side of the pedalboard. If you only rarely actuate the pedal’s switch, consider placement in the top right corner region.
- The final pedal in your signal chain benefits from placement along the lefthand or topmost side of the pedalboard. If you only rarely actuate the pedal’s switch, consider placement in the top left corner region.
- More complex signal chains that use effects loops, stage monitors run from the pedalboard, or blended wet/dry outputs to a mixer will generally place quite a jacks (4-8) along the perimeter of the board
D.3: Large Pedal Placement
Large pedals (wah, expression, preamp/DI boxes, workstations, etc.) should be placed early during the layout planning cycle.
For the most ergonomic placement, rocker pedals should be placed in locations where they can be easily reached by the foot you use to modulate them. Many players forego ergonomics and instead opt for sonically intuitive placements (and possibly shorter patch cable runs); for example, they might place a volume pedal used as a clean boost or envelope filter to the right but a volume pedal used for swells and fades to the left.
The exact location of these units may not actually matter all that much if you don’t use them often and/or have an especially large pedal board.
D.4: Power Supply Placement
This section assumes you are using a power supply with isolated outputs.
The primary decision you face when placing a power supply is whether to mount the power supply above or below the pedal mounting surface. Mounting above gives you easy access to the power supply and simplifies the process of troubleshooting power issues whereas mounting below frees up additional space on the main board surface for additional units (note that you cannot mount units on the power supply itself since it needs to be able to shed heat).
Secondary considerations include leaving negative space for the placement of the power cord itself and assessing whether the power supply interacts with other circuits in a way that produces excessive noise. For example, some less-shielded power supplies induce noise in certain wah pedals; if this is the case in your chain, you may want to consider placing your power supply some place other than directly below a wah pedal.
The final part of placing a power supply is to ensure that you have adequate power cable lengths for each required connector type to adequately power all of your units; otherwise, you may be forced to omit or misplace certain pedals due to the limitations of your available power connectors. Some power supply manufacturers supply varying cable lengths for each connector type, so you can sometimes wait until after you’ve placed most of your pedals to finalize the placement of your power supply.
D.5: Prioritization and Ease-of-Reach
Now that you’ve made arrangements for your input and output sections, larger units, and power supply, you can begin arranging your remaining units.
For many players, this process is a balancing act between ergonomics (for physical ease of use), performer’s intuition (for seamless integration into performances), and signal routing complexity. Outlined below are a few general guidelines:
- Account for power plugs and patch cable plugs when placing pedals; make sure to leave enough negative space between the jacks and enclosures to account for their inclusion once the board is wired up
- Frequently actuated footswitches should be placed near your dominant foot or along the frontmost row of the board
- Contiguous units in your signal chain should be placed in close proximity to one another
- Footswitches should be located such that they are accessible without encountering interference from nearby footswitches, pedal enclosures, and/or switches/potentiometers
D.6: Cable Routing
Cable management is worth dipping your toes into once you’ve achieved a comfortable layout for your board. Well-managed cables can reduce noise and improve reliability of your board.
When routing cables, observe the following:
- Cable runs can be bound together using zip ties and bound to the board using zip ties
- Run patch cables in bundles
- Run power cables in bundles
- Label your cable runs
- Avoid tight bends and hard angles when routing cables
- Cables should have a little play, but consider avoiding overly long cables for any given run; excessive patch cable length can add up and may negatively impact signal clarity
- Avoid parallel runs of patch and power cables in immediate proximity whenever convenient; when you need to intersect patch and power cable runs, endeavor to do so at perpendicular angles
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bacchettadavid
Well-known member
Just picking up this thread where I left off middle of last year. I've got a dedicated electric uke on the way, so I thought it would be a good time to revisit this thread and finish it off. The finale of Part IV is coming soon.
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bacchettadavid
Well-known member
D.7: Example Layout Procedure
For this example, I am going to do the layout for a mid-size board with a relatively complex signal chain; this should cover most bases you’ll encounter in setting up your own board.
The signal chain for this board is:
As a whole, this signal chain would be for dual-instrument amplification in at-home and occasional live looping scenarios. Most of the complexity in this chain results from the inclusion of the bypass looper (orange rectangle) and a particularly well-appointed DI/preamp (brown rectangle). The orange bypass switch is used as a quick toggle for a few other effects (and to keep two noisy pedals out of the signal chain when not in use). The DI/preamp is a 2-channel input DI box with quite a few additional features. It receives signals via two channels and a switchable effects loop return. It sends signals via 5 mono channels as follows: tuner send, balanced pre-EQ and pre-effects send to FOH, buffered switchable effects loop send, balanced post-EQ a post-effects loop send to FOH, and a line out to a combo amp or stage monitor. The DI box also features anti-feedback tools and a mute switch. A player intending to occasionally use all its outputs would do well to ensure that sufficient space is provided around the DI box for cable routing.
Before proceeding with the layout, it’s generally a good idea to think about how each unit is used. Since the board is used for looping, placement of the looper and footswitch controller will be important. The bypass switch is used to patch in tones set via the overdrive, octaver, and tremolo and so should remain accessible. The compressor is used to lightly squash the signal as well as provide a little lift for single-note runs. The volume pedal is always on and is used as a volume knob or envelope filter; it will work best when placed near the player’s dominant foot. The reverb and delay are always on and are used to round out the signal and give it a bit more body. The tuner is always on.
Setting up a board like this is relatively complex, and our board doesn’t afford us much excess space. To help ensure we leave enough negative space for foot clearance and plugs as we consolidate the placement of the units, I’ll begin by mapping out all the input, output, and power jacks for each unit:
Fig. 1: Inputs and outputs are indicated in green; power jacks are indicated in red.
And with that knowledge, we are ready to place a few of the larger and more awkward pedals:
Fig. 2: Large Pedals Placement
This placement prioritizes ergonomics of the volume pedal and loop controller footswitch for a right-foot dominant player while also minimizing the amount of real estate consumed by the preamp/DI box. Because the preamp/DI is placed toward the midline of the board, additional negative space has been provided for the inputs and outputs on either side of its enclosure to facilitate the insertion/extraction of any cables.
One notable weakness to this layout is that necessitates the use of longer instrument cables due to the central rearward placement of the DI box instrument inputs. Note also that the power supply is too large to be mounted on top of the board and will have to be mounted underneath. The tight spatial restrictions and large number of effects units preclude the otherwise preferable top-mounted placement.
We will now proceed with some of the easier placements for this signal chain:
Fig. 3: Simpler placements
The looper has been placed along the bottom perimeter of the board in immediate proximity to its controller. This will ensure that the looper is relatively easy to use. The compressor, which is frequently used in this setup, has also been placed near the looper so that it can be used either as a clean boost or switched on to add sustain and even out single-note runs during solos. The tuner has been relegated to the far reaches fo the upper left corner and rotated 90 degrees to mitigate interference with the line out from the DI box.
This forms the core of the signal chain and board. If plugged into a PA or combo amp with built-in reverb, this layout would be gig-ready. However, we are going to add some effects units for tonal variety and a bypass looper to switch them into and out of the chain:
Fig. 4: High-priority, technical placements; green overdrive should be placed slightly lower than indicated in the figure to make room for its power plug.
Like the looper, the bypass switch has been added along the bottom edge of the board to facilitate ease of use, with its associated effects clustered around it. This will allow us to quickly and quietly set up instrumental timbres which can be switched on or off using the bypass looper’s switch.
This placement does present one issue: the green overdrive is a relatively tall pedal whereas the DI box has a short enclosure. Access to the effects loop/boost switch in the middle of the preamp/DI is somewhat impeded by the placement of the overdrive. Unfortunately, no simple solution exists. The overdrive has a slanted footswitch that would no longer be facing the player were the unit rotated 90 degrees to prevent this interference.
Lastly, we will incorporate the reverb and delay:
Fig. 5: Low-priority placements
The reverb and delay could switch places with relative ease depending upon player preference.
Of course, there is more than one way to lay out most pedalboards, and you’ll have to consider your particular constraints as you approach the layout for your own board.
The last thing we’ll examine in Part IV is cable routing for the above layout. Stay tuned.
For this example, I am going to do the layout for a mid-size board with a relatively complex signal chain; this should cover most bases you’ll encounter in setting up your own board.
The signal chain for this board is:
As a whole, this signal chain would be for dual-instrument amplification in at-home and occasional live looping scenarios. Most of the complexity in this chain results from the inclusion of the bypass looper (orange rectangle) and a particularly well-appointed DI/preamp (brown rectangle). The orange bypass switch is used as a quick toggle for a few other effects (and to keep two noisy pedals out of the signal chain when not in use). The DI/preamp is a 2-channel input DI box with quite a few additional features. It receives signals via two channels and a switchable effects loop return. It sends signals via 5 mono channels as follows: tuner send, balanced pre-EQ and pre-effects send to FOH, buffered switchable effects loop send, balanced post-EQ a post-effects loop send to FOH, and a line out to a combo amp or stage monitor. The DI box also features anti-feedback tools and a mute switch. A player intending to occasionally use all its outputs would do well to ensure that sufficient space is provided around the DI box for cable routing.
Before proceeding with the layout, it’s generally a good idea to think about how each unit is used. Since the board is used for looping, placement of the looper and footswitch controller will be important. The bypass switch is used to patch in tones set via the overdrive, octaver, and tremolo and so should remain accessible. The compressor is used to lightly squash the signal as well as provide a little lift for single-note runs. The volume pedal is always on and is used as a volume knob or envelope filter; it will work best when placed near the player’s dominant foot. The reverb and delay are always on and are used to round out the signal and give it a bit more body. The tuner is always on.
Setting up a board like this is relatively complex, and our board doesn’t afford us much excess space. To help ensure we leave enough negative space for foot clearance and plugs as we consolidate the placement of the units, I’ll begin by mapping out all the input, output, and power jacks for each unit:
Fig. 1: Inputs and outputs are indicated in green; power jacks are indicated in red.
And with that knowledge, we are ready to place a few of the larger and more awkward pedals:
Fig. 2: Large Pedals Placement
This placement prioritizes ergonomics of the volume pedal and loop controller footswitch for a right-foot dominant player while also minimizing the amount of real estate consumed by the preamp/DI box. Because the preamp/DI is placed toward the midline of the board, additional negative space has been provided for the inputs and outputs on either side of its enclosure to facilitate the insertion/extraction of any cables.
One notable weakness to this layout is that necessitates the use of longer instrument cables due to the central rearward placement of the DI box instrument inputs. Note also that the power supply is too large to be mounted on top of the board and will have to be mounted underneath. The tight spatial restrictions and large number of effects units preclude the otherwise preferable top-mounted placement.
We will now proceed with some of the easier placements for this signal chain:
Fig. 3: Simpler placements
The looper has been placed along the bottom perimeter of the board in immediate proximity to its controller. This will ensure that the looper is relatively easy to use. The compressor, which is frequently used in this setup, has also been placed near the looper so that it can be used either as a clean boost or switched on to add sustain and even out single-note runs during solos. The tuner has been relegated to the far reaches fo the upper left corner and rotated 90 degrees to mitigate interference with the line out from the DI box.
This forms the core of the signal chain and board. If plugged into a PA or combo amp with built-in reverb, this layout would be gig-ready. However, we are going to add some effects units for tonal variety and a bypass looper to switch them into and out of the chain:
Fig. 4: High-priority, technical placements; green overdrive should be placed slightly lower than indicated in the figure to make room for its power plug.
Like the looper, the bypass switch has been added along the bottom edge of the board to facilitate ease of use, with its associated effects clustered around it. This will allow us to quickly and quietly set up instrumental timbres which can be switched on or off using the bypass looper’s switch.
This placement does present one issue: the green overdrive is a relatively tall pedal whereas the DI box has a short enclosure. Access to the effects loop/boost switch in the middle of the preamp/DI is somewhat impeded by the placement of the overdrive. Unfortunately, no simple solution exists. The overdrive has a slanted footswitch that would no longer be facing the player were the unit rotated 90 degrees to prevent this interference.
Lastly, we will incorporate the reverb and delay:
Fig. 5: Low-priority placements
The reverb and delay could switch places with relative ease depending upon player preference.
Of course, there is more than one way to lay out most pedalboards, and you’ll have to consider your particular constraints as you approach the layout for your own board.
The last thing we’ll examine in Part IV is cable routing for the above layout. Stay tuned.
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