Vertical positioning for F1-X?

[skyboltone]

Eddie, I don't know the F1-X that well and I don't have a scheme with me but there are a whole lot more than two caps in a F2-B. If your tech guy needs that information I suggest you find a new tech guy. Caps are a huge issue tonally. If I were going to do a cap job on mine I'd call Alembic and find out whatever they are using now. This of course, applies to the cathode bypass caps, the coupling cap, the three caps in the tone stack, the bright cap the deep cap or caps etc. For power supply filter caps there may in fact be just two. If that's what you are referring to, my apologies. Those are less critical tonally but once again, your tech should be able to replace them with the same value by checking visually. I have come to rely on Nichicon, though there are many other modern caps that will suit. I would not however, let him put any Xicons in there.  
 
Tube rolling. What a subject. It's nice to have a dozen or so 12AX7s, both vintage and new manufacture, to try out in the circuit. See which one sounds best to you. Your tech may well have some for you to try. Bring your rig and play several. There are distinct differences. If you are less critical or pressed for time or just find the whole subject kinda lame (many do) then call Alembic and see what they are using. I'm certain that they have done extensive research and have a preference among new manufacture tubes. Oh, also, get some DeOxit and spray the tube socket then stick the old tube back in and see if the frying egg sound goes away. It could be that simple.

[edwin]

Daniel, I think he was referring to the filter caps. Those are the ones that typically go bad the soonest.
 
As far as tube rolling, I tried a bunch of tubes in my F1X before I sold it to Ben, and I found that the effect of different tubes was minimal compared to other preamps, including the F2B. Perhaps it was due to the function provided by the tube in this design. The F1X is not an all tube signal path.

[skyboltone]

Thanks for the clarification Edwin. I have not, in fact, even gotten mine yet. I just sent the dough to a fellow here on the forum for his. I think too, as you say, bass rigs are far less tube critical than guitar amps. Guitar guys that I work with are Fanatical about V1 and willing to spend huge bucks to get it right. So I'll defer to all who actually own one and have used it in real conditions.  
Dan

[eddieg]

thanks guys:I believe Edwin is right. I do remember the caps that were replaced were cylindrical and there were four in a row in my F2-B. My tech told me the caps get brittle and crumble after an amount of time. I'll just have him look at them, that's what he did last time. I just thought I would try to give him a heads up on what to use. it is 18 years old too! so it's about time for some TLC.
 
 
peace
 
EddieG

[edwin]

It's not so much a bass vs. guitar preamp question as much as the fact that the F1-X uses the tube as a buffer for the input and at the FX loop return. It doesn't provide as much gain as you see in the typical Fender or other tube amp circuit. An F2B does use the tube for gain, so tube rolling there does provide more tonal difference.  
 
This is all assuming decent quality tubes. After all, they should adhere to the 12AX7 spec to good degree.
 
YMMV, etc.

[David Houck]

A few years back, Mica posted a note about tubes which can be found here.  And while I'm about it, other interesting things can be found in our FAQ section for the F-2B and F-1X.  There are also some very descriptive summaries on the product information pages for F-1X and F-2B.
 
The four big caps in the F-2B referred to in the above discussion can be seen in this picture.