Under saddle pickups

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eclipsme

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There is a very wide range of pricing for under saddle pickups - from a few dollars for a generic to $100 for a Fishman.

I understand a certain amount of generics will be doa, but is there really much of a difference in sound?

Thanks!
 
IME the differences come more from the installation variables (if it's under-saddle - is the saddle seated well, etc but also less obvious things like string tension and break angle, since they influence how much pressure the undersaddle element is under. If it's not under-saddle, where is it located, how is it attached, and so on) and the electronics (quality of the buffer design, filters or EQ built in or not, etc) than from anything else. I don't think there's any magic in a brand name piezo pickup itself. The good thing about brand name units is that everything is thought out as a coherent package and you have a vendor to support and stand behind it if there's an install issue or question.

Personally, I have recently started to use the generic super-cheap elements sold in bulk on eBay and my own preamp/buffers. My total cost per unit is probably around $6 or $7. You don't have to spend a lot to get good tone, but it's probably easier and more foolproof to do so. IME most of the cheaper brand name and cheaper generic packages give poor results either because they have terrible preamp designs (noisy, or poorly selected components, or design issues that cause bad tone) or the piezo is physically unsuitable for a good clean install (basic unfortunate things like shrinkwrap on the wiring at the end of the piezo interfering with a good fit, or the vendor just sells one single "one size fits all" undersaddle element that isn't suited for a particular installation, etc).
 
dwizum said:
IME the differences come more from the installation variables (if it's under-saddle - is the saddle seated well, etc but also less obvious things like string tension and break angle, since they influence how much pressure the undersaddle element is under. If it's not under-saddle, where is it located, how is it attached, and so on) and the electronics (quality of the buffer design, filters or EQ built in or not, etc) than from anything else. I don't think there's any magic in a brand name piezo pickup itself. The good thing about brand name units is that everything is thought out as a coherent package and you have a vendor to support and stand behind it if there's an install issue or question.

Personally, I have recently started to use the generic super-cheap elements sold in bulk on eBay and my own preamp/buffers. My total cost per unit is probably around $6 or $7. You don't have to spend a lot to get good tone, but it's probably easier and more foolproof to do so. IME most of the cheaper brand name and cheaper generic packages give poor results either because they have terrible preamp designs (noisy, or poorly selected components, or design issues that cause bad tone) or the piezo is physically unsuitable for a good clean install (basic unfortunate things like shrinkwrap on the wiring at the end of the piezo interfering with a good fit, or the vendor just sells one single "one size fits all" undersaddle element that isn't suited for a particular installation, etc).
Click to expand...

This is awesome. Can you provide more info on how you build the preamps?
 
Uke-alot said:
This is awesome. Can you provide more info on how you build the preamps?
Click to expand...

I have a design I use based on a J201 FET. I get the boards from OSH park:

https://oshpark.com/shared_projects/FUMGrz31

Less than a dollar each if you get the cheapest service and order 3 or more at a time!

I get the components from Mouser. I could dig out the BOM if you want to try making some.

This design is just a pure buffer, there's no EQ onboard. I don't like having controls on an "acoustic" instrument, I prefer to have them on the amp or a pedal. That said, I have built a few instruments where I used passive tone and volume controls downstream of the buffer - I used 100k pots and wired them like you would the tone and volume controls on a (passive) electric guitar. If you wanted an onboard active EQ, that would be very easy to add (I have some DIY designs EQs as well, but usually only install them on solid body bass guitars).

The J201 has a lot of variation in it's spec so there's a theoretical chance that you could end up with a part that's near the extremes of the spec and could sound "bad," but I've built a lot of these and have yet to have that happen. Some other designs based on the J201 include a trimpot on the feedback to allow it to be tweaked. They're so cheap that I figure if I ever get one that sounds bad, I'll just swap resistors "manually" to tune it instead of relying on a trimpot, leaving the pot off keeps the design smaller and simpler. The J201 is really perfect for this application, it's low noise and has very good, very natural tone. (Some people describe it as "tube like" when it's used in a preamp stage). It doesn't sound harsh or thin like a lot of cheaper preamps do. And it allows for a very simple circuit. Speaking of small and simple, it's so small it doesn't need to be "mounted" in the traditional sense. I usually just solder the pcb right to the output jack with really short stiff wire stubs. Then solder on battery leads and the pickup leads and you're done. This makes the install very clean. Sometimes on uke-sized instruments I sub out a stack of coin cells instead of the traditional 9v battery. It's smaller and lighter and easier to mount that way. In a uke, I like to put the battery on the head block since that seems like the best combination of out of the way and yet still accessible.

I've mostly given up on undersaddle strips unless people request them in a specific instrument. I prefer disk elements superglued to the bottom of the soundboard near the bridge. This way you get less "quack" from the element being under compression, and you get more freedom in terms of tuning the whole setup since you can play with the placement of the disk on the soundboard to make slight tweaks to the tone and volume. You can also play with different sized disks to adjust the output. It's Hard to get that kind of control with a strip under the saddle.
 
dwizum said:
I have a design I use based on a J201 FET. I get the boards from OSH park:

https://oshpark.com/shared_projects/FUMGrz31

Less than a dollar each if you get the cheapest service and order 3 or more at a time!

I get the components from Mouser. I could dig out the BOM if you want to try making some.

This design is just a pure buffer, there's no EQ onboard. I don't like having controls on an "acoustic" instrument, I prefer to have them on the amp or a pedal. That said, I have built a few instruments where I used passive tone and volume controls downstream of the buffer - I used 100k pots and wired them like you would the tone and volume controls on a (passive) electric guitar. If you wanted an onboard active EQ, that would be very easy to add (I have some DIY designs EQs as well, but usually only install them on solid body bass guitars).

The J201 has a lot of variation in it's spec so there's a theoretical chance that you could end up with a part that's near the extremes of the spec and could sound "bad," but I've built a lot of these and have yet to have that happen. Some other designs based on the J201 include a trimpot on the feedback to allow it to be tweaked. They're so cheap that I figure if I ever get one that sounds bad, I'll just swap resistors "manually" to tune it instead of relying on a trimpot, leaving the pot off keeps the design smaller and simpler. The J201 is really perfect for this application, it's low noise and has very good, very natural tone. (Some people describe it as "tube like" when it's used in a preamp stage). It doesn't sound harsh or thin like a lot of cheaper preamps do. And it allows for a very simple circuit. Speaking of small and simple, it's so small it doesn't need to be "mounted" in the traditional sense. I usually just solder the pcb right to the output jack with really short stiff wire stubs. Then solder on battery leads and the pickup leads and you're done. This makes the install very clean. Sometimes on uke-sized instruments I sub out a stack of coin cells instead of the traditional 9v battery. It's smaller and lighter and easier to mount that way. In a uke, I like to put the battery on the head block since that seems like the best combination of out of the way and yet still accessible.

I've mostly given up on undersaddle strips unless people request them in a specific instrument. I prefer disk elements superglued to the bottom of the soundboard near the bridge. This way you get less "quack" from the element being under compression, and you get more freedom in terms of tuning the whole setup since you can play with the placement of the disk on the soundboard to make slight tweaks to the tone and volume. You can also play with different sized disks to adjust the output. It's Hard to get that kind of control with a strip under the saddle.
Click to expand...

Thanks for that explanation. That's really interesting. So this is just a buffer (i.e. reduces impedance) with no gain? Could you plug directly into a guitar amp or mixer without a separate preamp with gain if you use this? I think that would be extremely useful. Also, does unplugging cut power, so you don't need to wire a switch somewhere?

As far as the pickup glued near the bridge goes, are you able to test it before gluing in order to determine the best location? I have wondered how that works....
 
I honestly don't remember if it has gain or not, but if it does it's a small amount. I plug these instruments directly into an amp - that was the whole goal, get the instrument to the point where it's plug and play and sounds great without a lot of fuss needed. It certainly doesn't need any more gain. Piezos really need impedance matching to sound good more than they need gain or EQ IME. You can take the signal from a bare piezo and give it a lot of gain and it'll just sound thin and piercing, but get the impedance matched and suddenly the bass comes back and it sounds full and balanced and natural without any tweaking. Piezo elements used in instruments usually have impedances in the hundreds of k ohms or multiple megaohms range. That needs to be several orders of magnitude lower for sending a signal over a long cable to an amp.

And yes, that design features "switching" with a stereo plug like you're describing, you just run the battery ground to the ring connection on the jack instead of directly to the pcb, and ground the board to the sleeve, then it connects/disconnects the battery and switches on/off as you insert/remove the jack.

I have popped disks off and moved them - during "experiments" you can use just a tiny drop of thick CA to tack them down, and they will pop off afterwards with some encouragement, or worst case you can peel them off like a sticker (which destroys the disk, but they're dirt cheap in bulk). Then use a bigger drop of CA when you find the right spot. You can also just leave the disk where-is and glue another one on and wire the two in series, etc. The sky's the limit. At the end of the day though, it becomes routine in that you know a given size of instrument needs the pickup in about X spot to sound good. For ukes that's usually right on the bridge patch. On some larger instruments (i.e. a guitar or acoustic bass) I've sometimes ended up putting them off center a ways since dead center can sound boomy with a big top that displaces a lot.
 
Thanks for the responses and additional questions!

Seems like it is hard to say how much is the piezo and how much is associated electronics, with a good amount of gray for personal preferences thrown into the mix.

The info on impedance is quite interesting.
 
dwizum, since you offered before, I would really appreciate it if you would post the components you use for the J102 buffer. Maybe a picture of how it looks when it's all soldered up, if you've got one? I would like to try making a couple of them.
 
Sure. It's pretty dirt simple. 7 components in total.

Mouser part numbers:
C1 4.7uF electrolytic cap 667-EEU-FR1H4R7
C2 10uF electrolytic cap 667-EEU-FR1H100
R1 3M resistor 660-RK73H2ATTD3004F
R2 2.2k resistor 660-RK73B2ATTD222J
R3 6.8k resistor 660-RK73H2ATTD6801F
R4 51k resistor 660-RK73H2ATTD5102F

For the FET I used 512-MMBFJ201

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Not much to see on a finished unit. I solder the caps on to the bottom with the leads left long enough that they can be bent over to lay flat against the board. The schematic shows pin headers on the pads on each side but I just solder lead wires right to the pads. Then once the lead wires are soldered on I slip a piece of wide shrink wrap over the whole thing. There's a GND pad on both sides of the board just out of convenience. Let me know if you build one!

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Ok, I think I understand now. I think I'll definitely try this out. I want to build one or more ukes with pickups, but "good" commercial pickup hardware does seem to be rather expensive (far more expensive than the sum of the parts). Just a clarification - do you use a mono jack instead of a stereo one?

Have you tried putting a piezo pickup on a banjo with this device, and if so, how did it sound?

EDIT: One more question. If your battery dies, do you then have zero output, or do you just lose the buffering feature and it sounds less than optimal?
 
Last edited:
dwizum said:
Sure. It's pretty dirt simple.
Click to expand...

Um... not so simple to me however. I just buy the LR Bags Hawahii five-O pickups and they sound pretty darn good to my ear. Very low quack. The main problem is the price as in ridiculously insanely expensive. They don't call them LR Baggs O' Money for nothing.

l-r-baggs-five-o-ukulele-pickup-system.jpg
 
There is loads of info on the 'net on this type of pre-amp/impedance matcher.
A Google search for J. Donald Tillman, Don Tillman, Tillman Preamp, J-Fet preamp or similar will provide enough bedtime reading for weeks.
Most pundits agree that it is a very useful device, with a sympathetic clipping pattern, full tone and long battery life.
I have tried versions with the older hard-to-get classic brands of J-Fet, several different generics, and other designated J-Fets and have not had an unusable result. This may be, of course, open to debate and conjecture as I have old ears (and a matching old body), so may not be hearing the whole sound spectrum. Careful re-biasing may be necessary for out-of-spec devices.
I started experimenting with this device years ago, mainly because of my refusal to put any electronics into the body of acoustic instruments (apart from peizo pickup/s and a jack ...obviously).
If you read just a fraction of the available material, you will see that there have been many J-Fets used successfully, although with some deficits compared to the J201.
My devices are jammed into small project boxes of about 80 x 50 x 30 mm that clip onto the guitar strap. They are self-switching through a stereo input jack (mono output). Most of the box volume is occupied by the jack sockets and the battery, as I have miniaturised the circuit board to suit the remaining space. The only problem here is forgetting to unplug the input lead, but thankfully, 9v batteries are cheap and readily available.
There are ways to increase the gain, (nominally around unison), by varying the values and number of caps involved, but there are other circuits more suited to higher gain requirements. All of this, and volumes more, is explained in many dedicated articles on a plethora of web sites, but remember to research thoroughly before committing to printing circuit boards.
 
Uke-alot said:
Ok, I think I understand now. I think I'll definitely try this out. I want to build one or more ukes with pickups, but "good" commercial pickup hardware does seem to be rather expensive (far more expensive than the sum of the parts). Just a clarification - do you use a mono jack instead of a stereo one?

Have you tried putting a piezo pickup on a banjo with this device, and if so, how did it sound?

EDIT: One more question. If your battery dies, do you then have zero output, or do you just lose the buffering feature and it sounds less than optimal?
Click to expand...

Haven't tried a banjo but I'm sure you could work something out. I've put these on ukes, uke basses, tenor guitars, short scale and full size acoustic guitars, and even solid body electric guitars and basses.

I wire these with a stereo jack to get the battery to switch off when it's unplugged - same as pretty much all active units are set up. The positive from the battery goes to the 9v pad. Negative from the battery goes to the ring terminal on the stereo jack. Ground pad on the pcb goes to the sleeve terminal on the jack. This way, when a cable is inserted, the ground circuit from the battery is completed and the unit gets power.

I have never had the battery completely die on one of these but I'd imagine you would get zero sound if it was totally dead. It is forgiving to low voltage though and gives plenty of warning as the battery gets near the end of it's life (you start running out of headroom and get some mild distortion/clipping on louder notes, and at that point you usually still have at least several hours of battery life left). I find that to be the case with most off the shelf packages too.
 
bazuku said:
There is loads of info on the 'net on this type of pre-amp/impedance matcher.
A Google search for J. Donald Tillman, Don Tillman, Tillman Preamp, J-Fet preamp or similar will provide enough bedtime reading for weeks.
Most pundits agree that it is a very useful device, with a sympathetic clipping pattern, full tone and long battery life.
I have tried versions with the older hard-to-get classic brands of J-Fet, several different generics, and other designated J-Fets and have not had an unusable result. This may be, of course, open to debate and conjecture as I have old ears (and a matching old body), so may not be hearing the whole sound spectrum. Careful re-biasing may be necessary for out-of-spec devices.
I started experimenting with this device years ago, mainly because of my refusal to put any electronics into the body of acoustic instruments (apart from peizo pickup/s and a jack ...obviously).
If you read just a fraction of the available material, you will see that there have been many J-Fets used successfully, although with some deficits compared to the J201.
My devices are jammed into small project boxes of about 80 x 50 x 30 mm that clip onto the guitar strap. They are self-switching through a stereo input jack (mono output). Most of the box volume is occupied by the jack sockets and the battery, as I have miniaturised the circuit board to suit the remaining space. The only problem here is forgetting to unplug the input lead, but thankfully, 9v batteries are cheap and readily available.
There are ways to increase the gain, (nominally around unison), by varying the values and number of caps involved, but there are other circuits more suited to higher gain requirements. All of this, and volumes more, is explained in many dedicated articles on a plethora of web sites, but remember to research thoroughly before committing to printing circuit boards.
Click to expand...

Thanks, this is good information. After briefly searching on those terms, it looks like the circuit diagram that dwizum posted is the same as the Tillman preamp. It looks like there is lots of ways to vary the basic design to include pots and/or frequency shaping, but the basic design looks like it does exactly what I would want it too. The gain is supposedly 3 dB.
 
Uke-alot said:
The gain is supposedly 3 dB.
Click to expand...

Yes, 3dB is a modest figure in terms of power gain. It equates to a non-logarithmic factor of ~2x.
With the typical voltage of a mid-life battery, the gain is enough to negate any line losses.
I have always considered that the main value of this device is as an impedance matcher rather than an amplifier, as a practical preamp will usually feature some form of adjustment for basic functions, and adding all the 'fluffy stuff' makes it too bulky for my application.
 
Tillman certainly deserves credit for popularizing the J201 in this application!

Tayda make a "universal" preamp/buffer kit based on the J201, which is nice if you want a board meant for experimenting, since they include extra pads for different circuit options. Also they have a little table that summarizes all the options, which is very helpful if you want some reference points to experiment from:

https://www.taydakits.com/instructions/jfet-preamp/pages/designators-and-components--22

I've tried a few other piezo preamp designs - the cafe walter design, which I can't find a link to right now, and the scott helmke mint box piezo buffer:

http://scotthelmke.com/Mint-box-buffer.html

Comparing them all, I find that the J201 designs have a pretty magic combination of characteristics - they're dirt simple (small, cheap, easy to make), and they sound great.
 
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