Tube Layout diagrams???

[Bluesburst]

Just wondering if someone knows the layout of the preamp tubes and what does what?

I’ve started to experiment with the preamp tubes last night and have come up with something quite interesting first up. I swapped what I believe are the two gain phase tubes from 12AX7 with 12AU7’s.

Apart from the obvious drop in gain, the immediate result is the reverb sounds like I expect it to. I bought a Van Amps Sole Mate reverb for my AFD, I even had Tim "AFD" it by matching the Tolex and use Marshall silver knobs rather than the standard chicken-heads. Very cool looking unit! Problem was the reverb is almost non-existent through the effects loop and harsh, nasty trailoffs when plussged in front. The reverb itself is fine and works perfectly with my other amps whether in front or in the effects loop.

There is clearly something around the gain stage that doesn't react well with many of my pedals in the AFD100 or one / both of those tubes are duff. The other aspect is now the amp takes a boost pedal in front much better and is usable rather than just being mushy. Perhaps I’ll get it set up so it’s natural gain is lower allowing the addition of some of my overdrive pedals to give some nice variations. I may even be able to use fuzz in the AFD!

The experimentation continues but the early results are very interesting!!! Once I get the preamp sorted then I’ll lash out for a set of KT-66 tubes for the power amp. That should then provide further warmth and smoothness to the tone.

[Mats A]

If you turn up the master on the AFD too much wich is quite easy on this amp the sound can get muddy. Remember there is quite a lot of gain on tap also. It´s not like your Plexi. Same thing with the old master volumes. If you have gain on 10 and turn the master past 6 or 7 the sound gets muddy.