Vox Ac30

Tele · Post by **Tele** » 29 Mar 2002 4:52 am

Is it possible to remove 2 output tubes to reduce the volume as on Fender TWins? Or would it harm the amp?? What about the impendance then?

Andy[This message was edited by Tele on 29 March 2002 at 04:53 AM.]

Jay Ganz · Post by **Jay Ganz** » 29 Mar 2002 8:51 am

Andy,
I've got a couple old 60's AC-30's, but
never tried that. It would definitely
affect the impedance though. On a Twin,
when you remove those two outside 6L6's,
you usually use an 8 ohm load instead of
the 4 ohm. Since the AC-30 load is
normally 16 ohms, things might get a bit
tricky. You'd also have to change the
cathode bias resistor on the EL84 tubes
from a 50 ohm to a 130 ohm.

Michael Brebes · Post by **Michael Brebes** » 29 Mar 2002 9:00 am

On the Matchless DC30, which is very similar to the AC30, they put in a switch to cut the power in half. It changes the cathode resistor to twice the normal value and cuts out two of the tubes, turning it into a 15W amp. I'll look thru my schematics and see if I can get the exact circuit info for you.

Tele · Post by **Tele** » 29 Mar 2002 9:30 am

I have an old 62 non-top boost combo here for repair, but its extremely loud, I guess it would be even at 15 Watts.
Btw, anyone has an AC30/6 "treble" schematic?? Wonder whats different to the bass and normal versions ( this is not the TopBoost version!!)
Andy

Tele · Post by **Tele** » 29 Mar 2002 9:56 am

These amps can be rewired for 8 Ohms use as well!!???

Jay Ganz · Post by **Jay Ganz** » 30 Mar 2002 2:16 pm

Yeah. See that little terminal strip on
the side of the chassis? You have to
loosen the screw, slip out the wire &
move it to the 8 ohm screw. Even the old
AC-15's have some volume to them. They
just break up a bit easier. The main
difference in each version of the AC30
are mainly the audio coupling caps.
The Normal & Bass version increase their
value at various stages in the amp to pass
more of the low frequencies. I do have
the schematic you need, by the way.
Just drop me an email sometime!
[This message was edited by Jay Ganz on 30 March 2002 at 02:21 PM.]

Tele · Post by **Tele** » 4 Apr 2002 8:35 am

Hey Jay

thanks alot, I'm out of town but will do soon..
andy