Introducing myself and DIY - ROG Fetzer Valve woes

[Isaiah]

Hi,
I've been lurking for some time (waiting for my account to be approved. Thanks, Aron! ), but here's my first post

I built the Fetzer Valve circuit on Runoff Groove, but using my
CIJ Mustang bass with it, there's a large amount of electrical buzzing.
Rolling the Tone control all the way down pretty much reduces the buzzing to nothing (I should say, it wipes out the frequency range where the buzzing is present), but then it's too muffled.

I'm sure it's not the circuit because I haven't read about anyone having problems with this circuit.

Could it be because my bass has a split single coil and no shielding?

I tried the Fetzer Valve with my drum machine (Boss Dr-55) and it was silent (until I presser 'Start' then it boosted the signal nicely).

I'm sure it's just picking up (and amplifying) the barely audible buzz that is already present from the single coils.

I've checked the biasing several times.
By ear, using a volt-meter.
No difference.


Looking forward to hanging out here
Thanks,
Alex

[Meanderthal]

 Hmmm... I'm not familiar with the Mustang bass(maybe I saw one in a catalog once?), although somehow I picture a Bronco... But the bronco's pickup is not split, and can get noisy...

A split coil(like a P-bass pickup) should be acting like a humbucker. If not, maybe the coils are mis-wired... Also, is the body cavity shielded? Are you using a battery, or a wart? Maybe the buzz is from the PS and a filter cap is needed...

Edit: oops, I see; no shielding... yeah, that might help...

[mars_bringer_of_war]

One thing to remember is that a booster (Fetzer Valve is basically a clean boost) will boost both signal and noise. So, if you had a little hum pre-booster build, it becomes a big hum.

[wampcat1]

probably a dumb question, but did you have an output cap on it? Everything grounded properly?
bw