F-1X problem - please help.

[6stringbassist]

I bought this quite recently, when I got it it wouldn't work with my bass plugged into either input, but it would when I plugged my bass into the effects return.
It then all of a sudden started to work, but was temperamental, sometimes it would work and other times it wouldn't.
 
I did email Alembic, but I only got one reply, that was to say that they hadn't received my previous emails, and to explain again what was going on with it, and they'd get back to me, I did that and they didn't.
 
Anyway, it's stopped working completely now, unless I plug into the effects return.
 
What I want to know is, if I detach the plug that connects the main inputs to the board, cut the plug off and solder the wires onto the effects return input, would it still work the same.  
 
I'm very happy with the sounds from it, it really is great, when it works.

[David Houck]

From the F-1X page at the main Alembic site:
 
The input is buffered by a cathode follower tube circuit, which is a unity-gain impedance matching amplifier to feed the guitar level effects loop. This gives minimum loading on the output signal from the guitar while driving the effects loop gear with the same signal voltage level as the guitar but at a lower impedance, to isolate cable and other loading effects from the guitar pickups.
 
So, I'm thinking that's not what you want to do.  It sounds to me like this could me a tube problem.  I would try replacing the tube.
 
You'll need to make sure the tube you get will fit inside the sleeve.  Not all AX7s are the same size.
 
If you haven't read through the FAQ section on the F-1X, there are a couple threads there on changing the tubes.
 
There is also a possibility that the inputs just need to be cleaned, i.e. exercised.  The FAQ for this is in the F-1X section here.

[6stringbassist]

Hi
Thanks for your reply.
I tried changing the tube, I fitted it with a Telefunken, a Jan Philips and a Mullard.
I read about the input exercising before I bought it, so that was the first thing that I tried.

[David Houck]

Well, I'm not an electronics guy, so I can't be much more help.  My next suggestion would be to take it to a good amp tech and have them test it.  Maybe between now and then, one of the other members might post something more helpful.

[edwin]

It could easily be dirty tube socket pins or perhaps a solder joint gone bad. Before you start cutting stuff out of the circuit, I'd try cleaning and retensioning the pins and then touching up the solder joints in that part of the circuit. Also, it could be the switching mechanism in the effects loop jack. They can get dirty and then you would experience what you describe.
 
Edwin
 
(Message edited by edwin on January 06, 2008)

[6stringbassist]

Hi
 
Thanks for everyones replies.
 
I've tracked down an amp tech.
 
http://www.chambonino.com/
 
He comes highly recommended, and says that he should be able to sort it while I wait.

[David Houck]

While you wait!  Cool!

[6stringbassist]

I've got it fixed, it was so simple.
 
There is a switch built in to the effects loop input socket, when a jack plug is inserted it switches this off, mine wasn't making contact properly in the 'on' position.
 
It now sounds like it should, thanks for all of your suggestions.

[David Houck]

Congrats!