F2-B --- how to connect?

[83_silberpfeil]

Just got a used F2-B --- s/n 77X.  
Need help on how to set up w my bass, power amp and cab.
 
I am using a Yamaha BB1200s active bass, Crown DC300a amp (bridged for mono), and Mesa 15 8 ohm cab.
 
Questions:
 
If I use channel A input, where do I connect my 1/4 inch cable from the bass --- input 1 or 2?
 
For output on rear of F2B, do I use 'A' or 'M'?
 
Anything else I need to be aware of?
 
Thanks!

[David Houck]

Hi Jon; welcome to the club, and congrats on getting an F-2B.
 
Input 2 has a 6 db pad on it; so if you think your bass is sending too much signal, you might want to use that one.  I use input 1 with my Alembic bass, but I don't turn the gain on the F-2B past 5.
 
Since you're just using channel A, then using output A is probably fine.
 
Our FAQ section for the F-2B is .
 
Enjoy!

[83_silberpfeil]

Thanks for replying Dave, much appreciated!!!
 
I Tried it again.  Bass to crown to mesa --- clean sound.  Next, tried only alembic to crown to mesa --- no bass.  When I turn on alembic it is still OK, but once I start turning the vol knob slowly from zero ---superbuzzz. Like a bad/incorrect connection.  Same for either a/b/m outputs.  
 
Based on this , w/o any input into the F2B, it looks like somthing is not right from F2B output into the Crown amp.  What do you think Dave?

[83_silberpfeil]

BTW Dave --- any way visually inspect the innards of F2B and determine if there are bad tubes or circuits?
 
Also --- thanks for the welcome!

[David Houck]

Is the superbuzz happening on channel B too?

[David Houck]

Alembic uses sealed, mil-spec, self-cleaning pots.  If the pots haven't been turned in a while, they may need cleaning.  To clean a pot, turn the knob back and forth through it's complete travel about thirty times.

[David Houck]

You might also check the jack-cleaning instructions here.

[83_silberpfeil]

Yea, superbuzz on A B M outputs

[David Houck]

(Note: I am not an electronics tech; you may want to have someone else here in the club, or a real tech, confirm the following suggestions.)
 
After you've cleaned the pots and jacks, you may want to open it up and check the interior.  Please unplug it and be very careful.  If you don't feel comfortable doing this, have an audio tech do it.
 
There is a nice picture of the interior .
 
The two large metal sleeves house the tubes.  You can visually inspect the tubes by plugging the unit back in and watching them glow.
 
I think it can also help to reseat the tubes.  Unplug the unit, remove the sleeves, then carefully pull the tube out and then put it back in.
 
Also in the picture, note the four big blue capacitors.  They are supported by a piece of felt.  If your F-2B is fairly old, that felt may need to be replaced to properly support the caps.  Visually note the connections.  If the felt is gone, the weight of the caps may loosen the connections.  I'm guessing you don't want to touch these if you don't know what you're doing.

[83_silberpfeil]

Dave --- Thanks again.  I opened her up and saw a piece of foam was just lying around --- not under the 4 blue caps.  I tried to p/u the foam and put under the cap, but the foam was old and brittle and disintegrated/crumbled.  
 
Further CAREFUL inspection of the 4 blue caps, I saw that only the one furthest to the left (channel B side) was actually attached/soldered to the 'vertical plane' circuit board.  The other three were not attached.  That, I believe is the problem.
 
I will contact the seller and see about getting a remedy to get it fixed, or refunded.  You've been a great help.  I will report back what I learn a bit later.
 
Cheers!

[mica]

That is the problem - the foam degrades over enough time (and your F-2B is around 40 years old) and the caps can vibrate off their leads. Sending the F-2B here for recapping is currently about a $65 job.  
 
Please note that there is HIGH VOLTAGE on the top trace of the circuit board, so if you are poking around an F-2B, give it a good 15 minutes to dissipate the capacitance.  
 
If you want to send the unit in for repair, please email me and I'll help make the arrangements.

[mica]

You might also want to familiarize yourself with the .

[83_silberpfeil]

DAVE --- I think we're get'n somewhere now.  It would be good to get a quote from Alembic so that I can present to the seller to help me settle the matter.  But, I like the idea of sending it in to Alembic to get it repaired/tuned-up!
 
Also --- I just noticed that the blue round 'dial looking thing with a top slot for a flat screw driver' is loose.  In the photo link you provided, it is that blue piece where the blue/white wires terminate.  What is that for and is it a problem that it is loose?

[David Houck]

If you need a printed quote, you should probably call the shop.  However, I'm guessing you could probably just tell the seller that you've corresponded with Alembic, maybe even link to this thread, and that they're estimating $65 for recapping.  You'll want to add shipping both ways when you discuss with the seller.
 
When they are inside an Alembic instrument, those blue things with the dial are for adjusting the gain output of the preamp.  However, I don't know what it's function is inside the F-2B.  If you send it to Mica, you might want to include a note about it appearing loose.
 
Personally, I highly recommend sending it to Alembic.  I have the highest regard for the people there and the quality of craftsmanship.

[83_silberpfeil]

Cheers Dave!  And, you've highly impressed me with your help.  I will follow your tips/advice and ultimately send to Alembic --- once I get the terms sorted out with the seller.
 
JC