Something Funky Going On

[hammer]

Recently, my Short Scale Series I has been having some weird stuff occur to it.  Several times at practices over the past two weeks, the volume has dropped noticeably while I'm playing to the point where it's not audible at all in the mix.  Twirling the volume knobs a few times typically brings the volume back up (though to ear splitting levels if the recovery occurs while I'm the the full gain position).  The first time this occurred, I rotated all of the knobs fully somewhere in the neighborhood of 50-75 times.  The next time I used the bass there were no problems but again last night the fade occurred.  Any ideas as to what the problem may be? 

[rv_bass]

Are you using the five-pin or batteries?  If batteries, maybe they are in need of replacement.

[hammer]

Five pin only. And I'm using a new Raydecker cord.

[adriaan]

Assuming you still have an old cord, have you doublechecked whether the problem is the new cord by itself?

[hammer]

I don’t think it cord related as it hasn’t occurred with another Series bass just my Series SC. It is weird that when it occurs when I’m practicing alone and can hear what’s happening solo, the decrease in volume occurs quite slowly over 15 to 20 seconds or so. No distortion at all, just a loss of volume.


I went through the process of exercising the self cleaning pots again last night for a second time. We will see if that makes a difference. It’s hard to pin down because it’s intermittent. I can go for a week or two with nothing happening and then experience the volume loss 2-3 times over a couple of days.

[rv_bass]

Maybe a resistor on the preamp board is wearing out.  That happened to one of my older basses and prevented any sound.  I sent it in to Alembic and had the resistor replaced and it works great now. 

[mica]

Have you noticed if the sound happen in both channels or just one? We might have to test your board to see the issue.

[hammer]

That would seem like a very logical thing to do... I’m not sure what it means that I have yet to do this. The next time it occurs (it hasn’t happened for the last two days since I went whole hog on exercising the pots) I will make sure I check that out.

[hammer]

After playing for 13-days with nothing occurring, my drop out finally reared its ugly head again tonight at practice. It appears to be a problem that only affects the bridge PU.  The neck PU continues to work fine. It occurred several times tonight lasting anywhere from 30 seconds to 2-3 minutes. Turning up the neck PU and continuing to play, the bridge PU appears to "recover" function after a while (to the consternation of my bandmates who get blasted for a few seconds.   It's definitely intermittent and seems to recover on its own.  All I did tonight when it occurred was to turn the gain up on the neck PU and eventually it appeared that the bridge.  So my previous fiddling with the controls and thinking that was associated with recovery was nothing but superstitious behavior.  Has anuyone experienced this before with a Series bass or have ideas as to what this might be?
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[David Houck]

Off the top of my head, now that you know it's related to the bridge pickup ...

Check to see that the bridge circuit controls are firm against the shielding paint.

Check to see that the bridge circuit pots and circuit boards aren't touching the shielding.

Check to see that the lead from the bridge pickup is securely connected to the board.

Another thing you can do is to switch the pickup leads and see whether or not the problem switches pickup circuits.

[hammer]

Thanks for the suggestions Dave. Given the intermittent nature of the problem, it may take a while to see if some of these things are the root of the problem but all of them make sense to me as possible causes.

[mica]

It sounds like the IC or the FET may be failing in that channel..