Piezo buffer question

[Arvin]

Hi all,

I just picked up a 5-string with the following configuration:

1) A pair of Bartolini Jazz pickups (not sure of the model, going to pull them later today and look them over well)

2) a piezo bridge

3) Master volume, Blend for the magnetic pickups, and Blend for the piezo/magnetic balance.

Inside the cavity, there's a Bartolini MPB-1 piezo buffer, but no other preamp. If I disconnect the battery, I get no sound from the bass, either piezo or magnetic.

So, my question:

I'm 99% sure I want to ditch the piezo bridge and just go with a straight passive Jazz Bass config. If I do so, is it likely that pulling the piezo buffer will drastically affect the tone and/or gain of the magnetic pickups?

Thanks!

[bassbenj]

Originally Posted by pseudocat

Hi all,

I just picked up a 5-string with the following configuration:

1) A pair of Bartolini Jazz pickups (not sure of the model, going to pull them later today and look them over well)

2) a piezo bridge

3) Master volume, Blend for the magnetic pickups, and Blend for the piezo/magnetic balance.

Inside the cavity, there's a Bartolini MPB-1 piezo buffer, but no other preamp. If I disconnect the battery, I get no sound from the bass, either piezo or magnetic.

So, my question:

I'm 99% sure I want to ditch the piezo bridge and just go with a straight passive Jazz Bass config. If I do so, is it likely that pulling the piezo buffer will drastically affect the tone and/or gain of the magnetic pickups?

Thanks!

I'm not personally familiar with the MPB-1 preamp, but looking it up online shows that it's more than a Piezo buffer. It's a dual channel magnetic/piezo active buffer and preamp. Hence it is operating on BOTH magnetic and piezo outputs (which is why bass quits without battery) So basically if you rip it out you'll be changing from an active bass to passive. You can just convert to a passive bass but probably the only way to tell what will happen to the tone is to temporarily wire it passive and see if you like the tone. Hopefully you can try this by simply wiring the magnetic blend output to the jack (remove buffer output wire to jack first)

[FBB Custom]

As bassbenj said, the MPB buffers both the magnetic signal and the piezo. There is usually an adjustable gain trim pot in with the package for the magnetic channel so you may loose gain. It will obviously no longer be a low-impedance (active) signal.

If you are sensitive to tonal changes going from high to low impedance, cable capacitance, etc., then you might notice a difference. Otherwise, should not make much difference as buffers are generally intended to be mostly transparent.

[Arvin]

Cool, thanks for the input.

I got to thinking earlier today that it really wouldn't hurt anything for me to just leave the buffer in, and remove the blend pot for the piezo/magnetic balance. Then I'd have room for a passive tone control, which I'd like to have on this bass anyway. I may give that a go first and play it for a while.