The Amp Garage

If this amp is something very close to a 100W Plexi with each pair of EL34's replaced by a KT88, and screen voltage essentially equal to the plate like the original, then you want to stay with the Marshall specs. Some had very high plate voltages (~550), but I would use a PT like Classic tone 40-18...

1k7 would mean more plate dissipation, and it would only take ~370V on the plates to hit 200% of Pa max (42W). In push-pull operation that is a semi-soft upper limit. With 2k2 and 450V, the max dissipation on the load line is 220%, which should be ok. 1k7 would be 284%. I have a tech friend that su...

I think you could drop a pair of KT88's into the 1959 schematic with the same 5k1 grid stop and 1k screen resistors, but perhaps lower the bias feed resistors to 100k. I would definitely use a 2k2 OT, and keep the plate voltage down around 450 if possible. So would the standard 1.75k OT not be acce...

I noticed a company called The Royal Amp company that makes an amp they call the MSG 100. From my research and talking with them they basically say it's a bone stock 1969 10,000 series Plexi with "minor changes" to the circuit with 4 KT88 tubes making just a little over 100w. My question is: If I we...

Yeah everything was working fine and the tubes had not been used before installing in that amp. They were NOS, but had tested almost perfect. So I don't know what happened there. After reading Mike's response it confirmed something I had suspected, but just hadn't tested.

It crossed my mind that one side of v1 may be bad. Just went and swapped it out and its working fine. Thanks Mike.

I recently built a JTM 45/100 and everything has been working perfect. I let a friend borrow it to try it out and had been jumping the channels. While he had it he said after he pulled the jumper neither input of channel 1 was working. Both inputs of channel 2 work perfectly fine. When you plug into...

If most of your taste as you posted is in the rock sounds of the late 60s to early 70s than that's Marshall town and the twin will not begin to come close to that without changing out the speakers to Clestions or a clone type and dropping bass response out of the amp in favor of mids! Unless that b...

Good tips. Truthfully I would vary my styles since I play different styles. I largely love late 60s early 70s hard rock. I have a LP custom with custom wound 59 PAFs and a strat with custom wound late 60s pups. I also love what I would term "hard blues" that vascilates between clean and dirt. I love...

If you were picking the perfect NOS tubes for each section of a 1965 Fender Twin Reverb what would you choose? If you had to choose modern day counterparts what would you choose?

There are several models that it may be, eg AB763, AB568 or an AC568. Whichever, in the first instance, how about just replacing the electrolytic caps, tighten tube socket contacts, check resistor values, check the bias is appropriate, then see how it sounds? I don't currently own one. I just wonde...

Is this a good candidate for blackfacing?

So is there an ideal schematic out there for a Plexi that would be good? What would be a good set of trannies for the build?

Also, what tubes are we talking? KT88's, EL34's

But if you don't want a lot of gain then why a 5000pf? Wouldn't that make the gain more extreme like this video comparison of bright caps demonstrate?

https://www.youtube.com/watch?v=N1_P07w0RlY

One thing to note on descriptives...the earlier classic tones where you hear what is referred to as "rawness" (I think KISS, I...(thunk)...wanna rock n' roll all night...), that can be achieved with a couple of warmer biased gain stages. The smoother, crunchy more modern sounds are typical of coole...