Vox AC10 SRT

[loctal]

Submitted for your approval.


Mod Edit: Thread title corrected for easier searching

[pullshocks]

Thanks for posting
I've been comparing this to the more well known AC10 SRT Amplifier schematic, Drawing Number OS/71.

The basic circuits seem very similar. I see some differences in the power supply circuit. On V2B, the plate resistor and coupling cap are correctly drawn, where the AC10 SRT had the cap between the plate and plate resistor. The two schematics differ on which triode of V3 does the reverb send and reverb return, though of course this would make no functional difference.

What is really confusing about the Super Reverb Unit schematic is how the dry signal gets to the power amp. In the SRT schematic the signal is split after V2A and returned from the reverb circuit after 470K and 100K resistors in series( hard to read the labels but I think it is R28 and R29). This is similar to most reverb amps I see, Fender uses 2 or 3 meg resistors, others use smaller values.

In the SRUnit, the signal goes straight from V2A to the reverb send, spring, reverb return, to V2B, and then on to the last gain stage, the cathodyne, and the output tubes.

So I just don't see a dry signal path, but I do notice there is a 22K resistor between the cathodes of V2 (present in both the SRT and the SRUnit ). Is that a signal path for the dry signal? Sort of like a cathode follower? To my limited knowledge, cathode follower stages have no plate resistor and a large cathode resistor.

[sluckey]

So I just don't see a dry signal path, but I do notice there is a 22K resistor between the cathodes of V2 (present in both the SRT and the SRUnit ). Is that a signal path for the dry signal?

yes

[mwaller]

I just finished building a clone of the AC10 SRT. OS/71 has several errors, including the placement of R28 and R29. The schematic at the top of this thread is 100% correct. The drawing number is OS/026.
The dry signal does indeed pass between the cathodes of V2 via the 22K reistor. Strange but true! The design of this circuit, including this cathode-to-cathode signal path is virtually identical to the original Ampeg Reverberocket.

Thanks for posting
I've been comparing this to the more well known AC10 SRT Amplifier schematic, Drawing Number OS/71.

The basic circuits seem very similar. I see some differences in the power supply circuit. On V2B, the plate resistor and coupling cap are correctly drawn, where the AC10 SRT had the cap between the plate and plate resistor. The two schematics differ on which triode of V3 does the reverb send and reverb return, though of course this would make no functional difference.

What is really confusing about the Super Reverb Unit schematic is how the dry signal gets to the power amp. In the SRT schematic the signal is split after V2A and returned from the reverb circuit after 470K and 100K resistors in series( hard to read the labels but I think it is R28 and R29). This is similar to most reverb amps I see, Fender uses 2 or 3 meg resistors, others use smaller values.

In the SRUnit, the signal goes straight from V2A to the reverb send, spring, reverb return, to V2B, and then on to the last gain stage, the cathodyne, and the output tubes.

So I just don't see a dry signal path, but I do notice there is a 22K resistor between the cathodes of V2 (present in both the SRT and the SRUnit ). Is that a signal path for the dry signal? Sort of like a cathode follower? To my limited knowledge, cathode follower stages have no plate resistor and a large cathode resistor.

[xtian]

I notice the date on the schematic is 1964. My question is, how did they know how awesome SRV was going to be at guitar?

[mwaller]

I notice the date on the schematic is 1964. My question is, how did they know how awesome SRV was going to be at guitar?

Someone needs to correct the title of this thread....

[pompeiisneaks]

That's pretty much on the post creator, I could, but I don't like overstepping my bounds

~Phil