Fender Bassman AA371 mods

[Joss]

Hey Guys

I modded my AA371 silverface to AA864, only the power stage and PI. The preamp remains original. I upgrade with some Orange drop 715/ Silver Mica the TS section and sounds more sparkle and open.

The amp have great dinamics ( too much for my taste ) and i would like to have more compression, slower pick attack at moderate volume.

How can I mod the amp for more compressed sound? The sag resistor not seems the solution, because sag effect only occurs at very high volume

Sorry my bad english, thanks in advance

Joss

[SyncTronX]

Hey Guys

I modded my AA371 silverface to AA864, only the power stage and PI. The preamp remains original. I upgrade with some Orange drop 715/ Silver Mica the TS section and sounds more sparkle and open.

The amp have great dinamics ( too much for my taste ) and i would like to have more compression, slower pick attack at moderate volume.

How can I mod the amp for more compressed sound? The sag resistor not seems the solution, because sag effect only occurs at very high volume

Sorry my bad english, thanks in advance

Joss

Thinking you have a tube rectifier right? Us a 5u4, a Bendix 5Y3, or 5R4.
don't use a GZ34/5AR4.

Thinking this is still new parts. Depending on what you used they are going
to be a bit bright right now. I think the 715s will break in in a bit
and not be so harsh. Als, What did you do with the electrolytics?
What value did you use on them? I think an amp cannot have
too much dynamic sound etc.

You mean the onlything you did was 715s and silver micas? But there are
resistors too, which ones did you use?

Post some pics of your amp.

[Joss]

Well, the AA371 model don't have tube rectifier. I tryed a sag resistor ( 100 -150 Ohms ) but the effect of compression is not noticeable at medium volume.

The electrolitics are news, sprague atom for filter caps and cathode bypass (I replaced the olds Mallory )

OD 715 for Tone stack, 47n and 100n, Silver mica for 250p

PI input cap 1n OD 715p, i like this value for my taste. 47n for output caps instead of 100n

The originals "Chocolate drop" for the rest

I use carbon comp resistors

Originally the amp has great dinamics, with the mod too

thanks

[booj]

Try replacing the 1k and 4.7k in the power supply with a 4.7k and a 22k to lower the plate voltage a bit. That should warm it up a little