Remove or bypass onboard controls

[soups]

Hi. I’m about the re-enter the field of acoustic amplification after around 15 years of complacency. I had a wonderful D-35 with a fishman matrix under saddle which was my main gig guitar for 16 years. It was stolen in 2016. By backup J45 was also outfitted with one but I’m looking to get back into solo gigging and everything under saddle these days has sound hole controls - which I do not want. Is there a simple way to bypass or even re-wire modern LR Baggs or Fishman pickups to cut out the controls?

Thanks!

[Peter Z]

Just solder the two wires from the UST pickup to tip and ring of the output jack. The inner, rubber covered wire to the tip, the outer wire mesh to the ring.
You can take the battery with the holder and the electronics out.
But you should use an external preamp (for piezos, high impedance) then.

[jparis51]

I'm curious as to how many folks have done this and have been pleased with the results using a reasonably good external preamp. Obviously bypassing the sound hole controls also means bypassing the onboard preamp, and I've wondered to what extent piezo quack is actually the result of the limited headroom afforded by a 9v battery.

[Cuki79]

Originally Posted by jparis51

Obviously bypassing the sound hole controls also means bypassing the onboard preamp

Not necessarly... I think you don't have to do what Peter Z suggested which is getting rid of the internal preamp.

Most preamp soundhole control are just
* passive filter like the tone pot on a Strat or a Les Paul
* passive attenuator (just a poteniometer making a voltage divider)

Schatten Design sells generic thumbwheel you can configure into any kind of combination of control. They work for all pickup preamps.

Schatten T-1 thumbwheel:


Schatten T-2 thumbwheel:
https://www.stewmac.com/globalassets...configurations

Unless you have an advanced preamp (Aura or Blend), if you know someone with a Multimeter and a small background in electronics, she/He could probably help you out and bypass the thumbwheel.

NOTA BENE: In your case the thumbwheel control is likely to be POST PREAMP/BUFFER.
Here is for example the signal chain inside a PZ-Deluxe from Radial Eng

One can see clearly the preamp comes first and then volume & tone.

My 2 cents,
Cuki

[soups]

Good points. I wouldnt necessarily want to eliminate the 9v battery. But I could if needed.

[noledog]

Originally Posted by jparis51

...I've wondered to what extent piezo quack is actually the result of the limited headroom afforded by a 9v battery.

There is a remarkable difference in this and have heard the difference in headroom for sure... I’ve been using MIJ Takamine guitars for the last decade replacing my old Lowden that had an onboard Fishman preamp and UST system using a 9v battery. The Tak Palathetic design pickup using the 9v onboard CT4BII preamp reduced quack to almost zero, much better then my Lowden’s system. However when I tried the interchangeable CT4DX preamp in the Tak that uses two 9v batteries the headroom was very noticeably better, cleaner and zero quack! UST’s do sound better with 18 volts no doubt from my experience.

[jparis51]

Interesting! The D-tar Wave-Length used two 9v batteries as well and they were pretty well-regarded.