Crate amp topology question

[Easto]

Hello,
I have a Crate Vintage Club 50. It has 2 - 12AX7s and 2 EL84s. This amp has 2 channels, 1 "Clean" and 1 "Distorted" i.e. the second channel has Gain and Volume adjustments. The amp was way to loud for my tastes and my amp tech suggested that I try some 12AY7s in different slots until I found the combination that worked for me. He assured me (being a Crate repair station) that these would not hurt the amp in any way.

I was also able to find this schematic. This is of the 30 watt model VC3112 and mine is the VC5212 50w model.

Preamp: schematicheavencom.secure.powweb.com/newamps/crate_vc3112_preamp.pdf

PowerAmp:
schematicheavencom.secure.powweb.com/newamps/crate_vc3112_poweramp.pdf

The preamp tubes are indicated by V1,V2,V3&V4.

Am I correct in assuming that V1 is the only preamp tube for channel 1? And that V2&V3 are the tubes for the "distorted" Channel #2? And that V4 is the driver tube that pushes these preamp signals into the poweramp section?

[Trey]

Switching to 12AY7s won't make the amp that much quieter, it will just lower the distortion on the amp and give it more headroom. Which means you would have to turn it up louder to get any overdrive...

[UnklMickey]

trey said:

Switching to 12AY7s won't make the amp that much quieter, it will just lower the distortion on the amp and give it more headroom. Which means you would have to turn it up louder to get any overdrive...

I agree.

I'd also point out that if you want a quick fix tube swap to reduce gain, 12au7 will reduce it much more and 12at7 will reduce it to a level between the 12ax7 and the 12ay7.

12at7 and 12au7 are easier to find than the 12ay7 and likely less expensive.

if you're looking to get to power amp distortion at lower levels the simple way is with a power sink.

a better way is to have your tech lower the supply voltage to your output transformer (and rebias accordingly). a resistor in series and a small to medium cap will provide a nice sag.

if he's really slick, he'll install a switch to allow you to also use it as stock.