Preamp for Electric/Acoustic?

cdkrugjr

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Looking to get a "acoustic with a pickup," not anything solid-body like a Konablaster.

What about a pre-amp?

Primary application will be playing direct into house sound system.

Secondary will be as "Yet Another Way" to get sound into my computer.

While an acoustic amp is on my "someday maybe" list, I don't currently have a reason to get one, nor the inclination to haul it around on Shanghai public transportation.

Looking for sub-$500 solutions. Sub-$200 is even better. I'll consider anything from "use a stomp EQ upstream of the DI to be sure you don't have horrible impedance mismatches" (necessary on early Piezo pickups, but not so much now) to "There's this handy box <maker> makes...."

Acoustic modeling pickups all seem to be based on various "We can't say we're modeling Martins but..." Are those models at all useful for uke?
 
Unless you use a preamp, DI box or inline-transformer with a passive piezo pickup, you will have an impedance mismatch into just about every PA system and/or guitar amp.

A piezo typically has an impedance of at least 1M-Ohm, that's 1 Million ohms, while an electric guitar is typically between 1-2 K-Ohm, as in 1 thousand Ohm, (which is what a guitar amp expects at the 1/4" guitar input jack) and most DYNAMIC (as well as phantom-powered condenser) microphones output from 150 Ohms to around 600 Ohms (which is what a PA system or MIXER expects at the MIC input jack).

What this means (in an abridged version) is that if you put the output of a piezo into a device that expects a lower impedance at it's input, you are not giving it the proper input signal, and will have problems and bad sound.

Going direct into a PA from a passive piezo is a bad idea because:

a) impedance mismatch will result in low signal volume into the PA
b) impedance mismatch will result in almost all audio frequencies below 500hz to be lost, similar to a hi-pass filter @500hz
c) impedance mismatch will result in the dreaded piezo 'quack' and basically sound terrible
d) cable runs longer than 10ft that are not via BALANCED TRS 1/4" or XLR cable are highly susceptible to hum and interference, as well as gound loop issues - MOST standard 1/4" 'guitar cables' are NOT balanced and are NOT 'TRS' but are 'TS' only.

A few sub-$50 USD ways to solve these problems:

a) use a Behringer ADI-21 digital preamp/directbox ($29)[many folks here on the forum SWEAR by these]
b) use a Behringer MIC-200 TUBE preamp/directbox ($39) [I have one of these and like it a lot]
c) use an A.R.T. Tube MP Studo TUBE preamp/direct box ($49) [I ALSO have one of these and like it a lot]

as well as using ONLY XLR cables from the output of any of the above when you are going INTO the PA system.

All of the above are smaller than an iPad (about double the width of a standard guitar pedal) and can fit in a small carry bag or backpack, but only the ADI-21 offers to be battery powered, the others run on either 9v A/C or 12v A/C and will need wall power. The above are also necessary with OR withOUT a preamp that is built-in to your uke if you want to have proper impedance matching as well as a clean signal going into the PA, unless the PA has a special 'guitar input' as a very select few do...

As Brad has said below the L.R. Baggs units, (and the Fishman Aura series) are also considered 'professional grade' equipment and are more ruggedly built than the items I suggested above, but are at least 3x-7x the price of the items I listed above.

Hope this helps, if not, please let me know...:)
 
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Anything LR Baggs is highly regarded. I've got the Venue DI and it does everything you could hope for. The new Session DI has some other features, but sacrifices the EQ section. Someday we'll get it all in one...
 
In the days before I saw the light and went over to using a mic, I swore by an LR Baggs Gigpro. Small, simple, solid, clips onto your belt, sounds great, battery lasts forever. This doesn't have a DI (XLR) out, but that suited me as most venues I play have DI boxes already setup as part of the stage gear. On the occasion I did need a DI, I had a cheap one in the gig bag.

Before I got that I did have the Behringer ADI-21. Not as roadworthy, being plastic, but far better than it had any right to be for the price.
 
related question not worthy of a new thread, but what does a quack sound like with a uke? I think I have noticed the low cut filtering when plugging my Risa directly into most amps. Is the quack sound less like a duck and more like a buzzing when playing with a stronger strum?

thanks,
kelly
 
Yes, Booli, that's exactly what I needed to know.

Looks like it will suit nicely until the budget allows better.
 
Get a pickup that includes its own pre-amp, then you don't have to worry about carrying a box in your pocket or have one on the ground with extra cables to trip over. Often the preamp is hardly any bigger than a slightly thickened cable.

http://www.lrbaggs.com/pickups/five-o-ukulele-pickup
http://www.fishman.com/products/view/matrix-infinity-1
http://www.fishman.com/product/ellipse-matrix-blend-1

I am with Phil about mics, though. I have yet to hear a decent sounding pickup. But the convenience factor is compelling if you gig a lot or are in noisy rooms all the time.

Brad Bordessa, cool! I have been using your chord thing obsessively while learning jazz standards.

ohmless, "quack" is the harsh, nails-on-chalkboard sound you get from piezo pickups. It can be softened by mixing the signal with a mic and dialing way back on the highs. Here is an example of a guitarist getting a lot of quack: https://youtu.be/U3xcAzB9x9s?t=9s
 
I've installed a number of cheap Chinese preamp/tuner pickups in my ukes and bass ukes and I find them to work very well, I especially like the Joyo models. I buy them from the AliExpress.com site. Out of the 10 or more I've purchased, only one was bad out of the box. I prefer not to carry any additional items.
 
Looking to get a "acoustic with a pickup," not anything solid-body like a Konablaster.

What about a pre-amp?

Primary application will be playing direct into house sound system.

Looking for sub-$500 solutions. Sub-$200 is even better. I'll consider anything from "use a stomp EQ upstream of the DI to be sure you don't have horrible impedance mismatches" (necessary on early Piezo pickups, but not so much now) to "There's this handy box <maker> makes...."
Second of all, I'd suggest not limiting your ukulele purchase based on the models that have pickups installed. Get your instrument, then have your pickup installed.

First of all, read the stickies at the top of Tech Talk.

You can get an LRBaggs Five.O installed at HMS for about $200, and you could go direct into the board without a DI - you'll use the line level 1/4" insert, and not the mic xlr. I'd start here after you get your instrument.

However, add another $170 and get a Baggs Para Acoustic DI (or Venue for about $300), and you can run a length from large stages (you don't want a 20' instrument cable). Nice features, including running off of phantom power.

Even if you don't do large stages, both will set you back less than your top budget, and you'll be set for live sound anywhere.
 
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Get a pickup that includes its own pre-amp, then you don't have to worry about carrying a box in your pocket or have one on the ground with extra cables to trip over. Often the preamp is hardly any bigger than a slightly thickened cable.


I'm assuming we can add the MiSi Acoustic Trio to the list?

Question for no one in particular:

Do these types of piezo with built-in pre amps also benefit from going through a DI box?
 
I got the Behringer ADI21. As much as I use it, it's great.
 
I'm assuming we can add the MiSi Acoustic Trio to the list?

Yes, of course. Mi-Si is my preferred installed pickup/preamp since it requires the least modification to your instrument and uses a rechargeable capacitor instead of a battery that you have to replace over time (wasteful to me when better technology exists for little extra money).

IDo these types of piezo with built-in pre amps also benefit from going through a DI box?

Yes, a DI box, even a passive one will not only have an impedance-matching transformer inside, but will also offer the conversion to XLR balanced cables, which is essential for longer cable runs, and helpful for shorter cable runs to reduce (hopefully to a negligible level), all sorts of EM/RF interference, noise and hum due to the capacitance of the cable.

While you MAY be able to get by with a standard guitar cable at lots of venues, they are typically NOT 'balanced' cables, and if the venue itself is causing the problem with poor A/C shielding, grounding and isolation with regard to the sound system setup, you are basically at their mercy.

See here why balanced cables are important:

http://www.brighthub.com/multimedia/audio/articles/98019.aspx
http://www.perreaux.com/blog/2012/2/27/Balanced-vs-Unbalanced-Audio

and if you are a glutton for punishment with tech jargon, or more advanced about sound engineering and don't mind seeing some schematic diagrams, see this article too:

http://www.rane.com/note151.html
 
related question not worthy of a new thread, but what does a quack sound like with a uke? I think I have noticed the low cut filtering when plugging my Risa directly into most amps. Is the quack sound less like a duck and more like a buzzing when playing with a stronger strum?

thanks,
kelly

Good question...

The quack is heard at the point of attack of the strings.

Think of almost slapping your hand down on top of a desk, and that 'quack', 'fwap' or 'slap' sound occurs at the instance of the sound, concurrent with everything else you hear from the 'pickup'.

This occurs partly because of the hi-pass effect due to impedance mismatch, but also due to the fact that most piezo elements, whether the 'brass' disc type, rod or cable UST type, or the PVDF film type have a VERY short distance that they travel in response to the sound due to being more rigid than flexible.

All of the above (piezos) are made from a crystalline structure that is similar to what is commonly known as Rochelle Salts, and the brittle crystals to not travel very much in response to the pressure applied to them.

This is very different from if say you look at the speakers in your home stereo. If you look at the woofer (the biggest speaker element in the box), you will notice that it moves quite a bit when music is playing, and it moves even more so when there is lots of bass.

The piezo is exactly the opposite of this and simply cannot move as much.

For a total geek-out: if you are on parts-express.com or crutchfield.com and looking at speaker components, this 'movement' or 'displacement' of a wooofer or sub-woofer is referred to as X-max or Xmax.

Many of these woofer-type elements have either rubber or accordion-paper surround on the speaker cone to allow for the travel induced by the electromagnet in the voice-coil, which you see and hear as vibration through the air.

By Contrast, a piezo is not afforded this great amount of travel (as opposed to almost EVERY microphone, whose diaphragm is quite flexible in comparison to a piezo), and the piezo is in effect using whatever surface it is coupled to as it's diaphragm, and thus is also referred to as a 'contact mic'.

Sorry if I may have already gone off the rails here...it's hard to explain.

Please let me know if this makes any sense. :)
 
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