Mag & Piezo for Wishbass question.

Bare Bass

Bare Bass

Feb 23, 2016
319
258
4,551
Saint Paul, Minnesota
#1
Hey, I want to install a piezo pickup under my Wishbass JB bridge. The bridge is walnut, handmade, the piezo will be one of those ultra-thin, tape-like pickups from Pickup the World, and I'll swap out the 'stock' KA MM-style mag pickup for a Häussel walnut-covered MM pickup. I was thinking of running the piezo through a John East treble/bass stack and the mag pickup through a John East mid/mid stack and then blending them through a BARTOLINI MPB2918 Magnetic And Piezo Buffer/PreAmp w/25 Trim Pot. That would then go through a volume pot before exiting through an output jack.

Any thoughts?

I'm a total newbie when it comes to this stuff, so don't hesitate to talk down to me, I won't be offended.
 
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#2
Firstly, as far as I know, the J East preamps do not have an appropriate input impedance for piezos. You want at least 3M to 5M Ohms, whereas the average preamp built for magnetic pickups has an input impedance of 1M or lower. You will have to check the spec sheet for that preamp, to be sure, though.

Secondly, you don't want to chain gain stages unnecessarily. If the magnetic pickups have a preamp/buffer, and the piezos have a different preamp/buffer, then there is no need to have a third preamp/buffer in the circuit. You will only be decreasing the headroom, adding noise, and degrading the signal, by adding the extra one.
 
#3
Bare Bass said:
I was thinking of running the piezo through a John East treble/bass stack and the mag pickup through a John East mid/mid stack
Click to expand...

Are you trying to have different EQ bands for different pickups? Preamps don't work that way, unless you have modular systems where each band is its own circuit. If you do get it working, however, it will not be the least bit practical to have bass and treble for one pickup, and mids for another.
 
#4
line6man said:
Are you trying to have different EQ bands for different pickups? Preamps don't work that way, unless you have modular systems where each band is its own circuit. If you do get it working, however, it will not be the least bit practical to have bass and treble for one pickup, and mids for another.
Click to expand...

Edit: Sorry, I see you've already answered this question (Piezo tone control). I'll leave the below though, just in case it's helpful.

Thanks for your feedback. Yes, I'm trying to have different equalizing ability for each pickup using single stack modules: SINGLE STACK MODULES - BASS.

The mag pickup on my Wishbass JB model is very close to the bridge, so it gets a real mid-y, Jaco sound. The piezo I haven't heard yet, but I'm assuming it will be like a lot of piezos and be somewhat brittle in tone. So the idea was to actively cut back on the mid in the mag pickup, to bring up both the bass and treble, and to actively manipulate the bass and treble on the piezo bridge pickup in order to tame the brittleness. Then I wanted to run both pickups, after tone modification, through a blender, then out to a master volume, then out to the amp. The buffer/blend is a BARTOLINI MPB2918 Magnetic And Piezo Buffer/PreAmp w/25 Trim Pot (Amazon.com: BARTOLINI MPB2918 Magnetic And Piezo Buffer/PreAmp w/25 Trim Pot: Musical Instruments).

I know something like this can be done, because I saw it on the Ibanez Portamento bass I briefly owned before returning it. It has something called an AeroSilk system:

"The EQ section incorporates the controls of the Bartolini pickups with the AeroSilk Piezo system. Controls include a neck volume, bridge volume and bass & treble controls for the Bartolini MK-1 pickups and a Master volume and a tone control for the Piezo system."

If my proposed layout won't work like this, any suggestions about how I might achieve my desired results (tone controls for both the very-close-to-the-bridge mag pickup and the bridge piezo pickup before blending them) would be greatly appreciated. Thanks.

Edit: would it work to run the piezo pickup through a Q-filter before it blends with the mag pickup? Would that be better than running the piezo through an active T/B module?
 
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#6
Only you know your budget and your threshold for pain. :) Do you have a purpose in terms of the tone you are after by adding the piezo?

Obviously I chose a somewhat easier and cheaper route, installing the two passive eqs with the single mag pickup. The mag pickup is probably close enough to the bridge that it is sensing substantially the same string sound and can have a similar, natural tone to the piezo, each with appropriate eq compensation.

So, I'm wondering if the piezo is sorta redundant and perhaps you should start by getting the mag pickup output sound to your liking and see if that is enough?

Otto
 
#7
ofajen said:
Only you know your budget and your threshold for pain. :) Do you have a purpose in terms of the tone you are after by adding the piezo?

Obviously I chose a somewhat easier and cheaper route, installing the two passive eqs with the single mag pickup. The mag pickup is probably close enough to the bridge that it is sensing substantially the same string sound and can have a similar, natural tone to the piezo, each with appropriate eq compensation.

So, I'm wondering if the piezo is sorta redundant and perhaps you should start by getting the mag pickup output sound to your liking and see if that is enough?

Otto
Click to expand...
Well, in theory, the piezo will pickup more of the string vibration, rendering a fuller sound, and also a more acoustic tambre. What I would like from the Wishbass JB is something between an electric and an acoustic sound. I just played it (with tapewounds) and it definitely feels woodier, but it also sounds that way. I don't expect it to sound exactly like an acoustic, but somewhere in between would be another sound to add to my repertoire. My luthier agreed a piezo would be a good option for this particular bass, as he was impressed by the unplugged tone of the thing, against expectations apparently.

The KA MM mag pickup gets an interesting sound right now. It's very Fender Jazz bridge pick-like, but somehow more organic, more woody or paper-y, less rubbery. I can't wait to hear how a higher end Haeussel pickup sounds with a little mid eq.

Anyway, gotta go get my daughter to the orthodontist. Then tonight I'm jamming with both the WIshbass and my trusty PJ with the new Cobalt Flats that Malak the Mad recommended. I've give a report tomorrow . . .
 
#8
Did you end up installing a piezo under the bridge on your Wishbass? I'm beginning to wonder if that might also be worthwhile to try on my Wishbass, which has that same issue with a mag pickup very close to the bridge.

I've improved it a lot with the two passive tones, but it still needs a pretty substantial amount of shelving eq to push the lows and low mids up about 12 dB. I could see getting a decent tone from a sandwich type pickup under the bridge.

Otto
 
#9
ofajen said:
Did you end up installing a piezo under the bridge on your Wishbass? I'm beginning to wonder if that might also be worthwhile to try on my Wishbass, which has that same issue with a mag pickup very close to the bridge.

I've improved it a lot with the two passive tones, but it still needs a pretty substantial amount of shelving eq to push the lows and low mids up about 12 dB. I could see getting a decent tone from a sandwich type pickup under the bridge.

Otto
Click to expand...
Yah, I put a Pick-up-the-World transducer pickup under the bridge. Sounds pretty good. Now I use the fuller piezo sound as the primary tone and the bridgy Haeussel pickup as coloration. The piezo has a treble/bass tone control and the mag a mid/mid tone control. On hindsight, I might've been better off with Noll's 2-knob, 3-band tone controls, but I didn't know they existed at the time. You might also consider one of Chris Stambaugh's bridges with Ghost piezo saddles. The under the bridge saddle on a solid body lacks a little note definition, but definitely gets a 'woody' sound.

I'm waiting for one last bass project to come in, then I'll post pics of the Wish bass and the others.
 
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