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AC30 info

BrianGWN

Great 'Double White' North ~ Electronics Specialis
Joined
Jul 15, 2001
Messages
1,401
I have a friend that has what I understand to be some kind of modern Vox AC30 reissue amp. He likes the tone he gets when it is really cranked, but not all the volume. As such it sounds like a candidate for a good output stage dual master volume mod. I haven't dealt with AC30s and similar before so I am not familiar with what I should expect to find "under the hood".
I guess I could start by looking for some schematics info to see what the output stage looks like, see if it looks to be suitable for a dual master. If anyone here knows some online source for AC30 schematics, or knows anything else about what is typically going on with these amps (output tubes, output section characteristics, what is any speaker impedance options there are), please do leave a note.
Thanks.
 

pablomago

New member
Joined
Jul 5, 2002
Messages
1,225
Most AC-30 guys that I know get a Weber Mass or other quality attenuator. They crank the amp and load it down with the attenuator. There is a simple mod for changing the Cut control into a Master Volume. But you lose the Cut control and that's one of the tings that makes an AC-30 special.
If you must have a master volume, Don Butler is one of the top Vox guys in the country. He's at www.toneman.com and can stear you in the right direction.
 

BrianGWN

Great 'Double White' North ~ Electronics Specialis
Joined
Jul 15, 2001
Messages
1,401
TedB said:
Assuming he has a '93-present reissue with tube rectifier:
Thanks TedB. I may get a chance to check out that amp tomorrow. If those schems you pointed to are a good representation of what I will find, a dual master should be no prob to install. It looks like the circuit uses something along the lines of a "long tail" phase inverter driving two pairs of output tubes that in turn use cathode self-bias, so modding to add a post phase inverter dual master should be straight forward.
 
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