How the JCM800 Circuit Works

[culturejam]

This is a great technical analysis of the JCM800:
https://robrobinette.com/How_the_Marshall_JCM800_Works.htm

Just thought I'd share. It's probably already been posted here, but I don't recall seeing it.

[pickdropper]

This is a great technical analysis of the JCM800:
https://robrobinette.com/How_the_Marshall_JCM800_Works.htm

Just thought I'd share. It's probably already been posted here, but I don't recall seeing it.

His site is great in general.  He breaks a lot of stuff down very well.

[mjcyates]

I built my first 2 amps (5f1, 5e3) using his layouts and they both turned out great!

[ahiddentableau]

Rob's site is the best.

Has anyone built any of his micro amps?  He has cool low power layouts of classic circuits (5E3, 5F6a, 5F1 are all there if memory serves) built around low power transformers (Hammond 270BX-ish power and fender reverb transformers used as a low power push-pull output) and tubes (12AU7 or 12BH7 dual triodes used in a single tube push-pull configuration).  I've always wanted to build one, but would like to hear some feedback beyond what's on the site.

[Manc]

Pretty good info, I was aware of this page and I keep going back to it as reference.
After a few direct clone builds I have started toying with the idea of putting together a high gain 18w JCM800 amp. Probably powered by a couple 6v6, with a SS rectifier.
I am also trying to figure out a switchable boost, to get a faux dual channel.
Robs pages are a mine of ideas!

[culturejam]

Pretty good info, I was aware of this page and I keep going back to it as reference.
After a few direct clone builds I have started toying with the idea of putting together a high gain 18w JCM800 amp. Probably powered by a couple 6v6, with a SS rectifier.
I am also trying to figure out a switchable boost, to get a faux dual channel.

What I really want to do is a single-ended version of this Phaez Daisycutter circuit (which sounds very Marshally):



Or the attached, which is similar but with a single tone control.

I know there are some of those out there that Phaez built, but I think it would be a fun project.

[Manc]

That is neat!
I also found a 18w power transformer (from Ampmaker) that has three secondary windings. You can connect a three way rotary to get 100%, 50% and 1/10th of B+!

http://www.ampmaker.com/store/0-190-275V-20W-power-transformer.html

[culturejam]

That is neat!
I also found a 18w power transformer (from Ampmaker) that has three secondary windings. You can connect a three way rotary to get 100%, 50% and 1/10th of B+!

http://www.ampmaker.com/store/0-190-275V-20W-power-transformer.html

That is awesome!

[Manc]

What's really good is that the heathers winding will always put out 6.3v
Sort of a Variac, but only where it's needed.

[culturejam]

What's really good is that the heathers winding will always put out 6.3v
Sort of a Variac, but only where it's needed.

Late 80s flashback