Hello again to all Alembic lovers!
 
I've noticed that there are 3 trim pots (2 in blue and 1 in green) on the other side of my PF-6B preamp card where the hum balance and gain controls are. The trim pots are visible when the preamp cavity is opened, while the card is still attached to the plate. (Please find attached JPG file for your review.)
 
It would be much appreciated if you experts out there could kindly provide some information on what those trim pots are for and how to control it (or better not make adjustements).
 
Many thanks,  
 
Andrew
 
 

Hi Andrew.  
I think you'll find that they're all blue. These are the trimpots used to control the 'amount' of signal coming from each pickup. There's an FAQ thread here.
 
Graeme

Graeme; on a PF-6, the trim pots you've referenced are on the the other side of the card and are available for adjustment through the holes in the cover plate.  I don't think the trim pots pictured above are the same thing.

Looks decidedly odd to me!!??

NOOOOOOOOOOOO
Do NOT adjust these trimmers. These are part of the calibration for the high frequency noise cancellation network and are not user servicable. In fact, they are usually covered with strong stickers to discourage fiddling.

Mica and Dave,
 
Thank you very much for your prompt support and advice. I've been reading lots of other materials from you and it is sure helpful a lot.
And thanks to other members as well!
 
Should I cover the trimmers with stickers/tapes or would it be OK as current?
 
Andrew

Only need to cover them if you ask someone else to service your bass or if you sell it.

Is that all the electronics for the Series bass or are there more hidden in the body somewhere else apart from the control cavity where the knobs are.?
Jazzyvee
 
(Message edited by jazzyvee on August 19, 2009)

There aren't any hidden electronics in a typical Series I or II bass or guitar. All electronics have access panels so repairs are possible.

I'm just surprised you get all that sound from apparently so few components.
 
I plan to give you a call in a bit Mica once I finish my dinner.
 
Jazzyvee

Dear Mica,
 
Thank you again for the clarification.
 
It's always great to know that your ultimate builder is there for you!
 
Andrew

Oh dear. I'm hanging my head in shame now. Just as well Dave and Mica were on the ball or my mistake could have caused untold suffering ;-(
 
Graeme
 
p.s. They still all look blue to me ;-)

I'd never seen the circuit board with the calibration  fitted either!
Now we all know what to look for.
 
G

That's ok Graeme; let me get you a beer.

One of these days I'll be in a position to take you up on that Dave ;-)
 
graeme