Tube Amp Archive

This one is labeled 45 watts

Can anyone help me id the circuit?

It's a bandmaster reverb with master volume.
Here are some pics

https://www.flickr.com/photos/terrydbur ... 813730191/

My 65 ampeg gemini g12 came with a permanent 12" speaker attached. I want to add a 1/4" female jack to the end of the speaker lines so that I have the option of switching the speakers in the studio. Is this as straightforward as it appears? As long as I connect to speakers with the correct resistanc...

Update: Problem solved! The issue was the reverb pot. Last tech did a number on it. Replaced the pot, no problem now. Wasn't all me. I spent a lot of time trying to crack this before setting it aside for a few weeks while I worked on other projects. Came across a retired EE who helped me troubleshoo...

Ok, i'm ready to do some signal probing.
My o-scobe is up and running along with my function gen. I assume i output a sine wave from funcgen to amp, then probe after the coupling cap on each stage?

Ruben at Music Go Round can either do it himself or will know someone who does. The guy is very plugged into the music scene in ABQ.

I touched the leads on that cap, the one coming off pin 6 on the 6cg7 and it pops when I touch either end.
It also pops the same with verb channel turned all the way down

Right, i did not measure 700vac. That's from my schematic. I haven't encountered another that matches.

Sluckey, mine more closely matches the first one that says patent pending at the bottom. Mine also has that.

A huge difference with my schm is that the voltage right before rectifier is 700vac. Yours says 280vac.

I've just realized that my schematic doesn't completely agree with the voltage chart. There don't seem to be any really early gemini schematics floating around.

I've replaced the two electrolytics on v7 and nothing blew up. Then today I powered her up and started tap components and leads with a chopstick. I found about 10 different spots on the turret board where it seems the solder joint is bad. These are all toward the center of the board where a lot of f...

I do not have a signal/function generator. Can I just play a 10mV sine wave via ipod into my amp for oscope diagnosis?

I made one of these for lower voltage projects like 500 series preamps.

All voltage measurements are relaive to ground except the heater pins. Voltage after c30 is 11vac Voltage between heaters is 12v In other voltage tests: V3, my 7199 phase inverter shold read 84v on pin 8. However, i'm seeing 46v V4/v5 both 12ax7 should read 185v on pin 6. They are reading 156v. V6 t...