JCM800 2204 diagram review

[a90s2cs]

I've been reading this forum for a while and its been very informative, I just never had a reason to post anything until now....  I'm in the beginning stages of JCM800 2204 build.  Did a lot of research and dug up half a dozen diagrams,  no two were the same.  Re-drawing diagrams is how I familiarize myself with circuits and ultimately come to understand them.   So anyway, I humbly submit the rough draft of my diagram, in both PDF & JPG, for review. I would greatly appreciate any critisism, advice or corrections. 

Thanks
a90s2cs

[sluckey]

Nice drawing. What software?

[SILVERGUN]

I don't have time to check it against a schematic but I submit this as another point of view.
That drawing does look nice.

[a90s2cs]

Thanks.  I use an outdated copy of Macromedia Freehand MX, circa 2004.  It was hands down the best vector software around until Adobe bought out Macromedia and stuck us with Illustrator.  What takes 30 seconds in Freehand takes 5 minutes in Illustrator.

[a90s2cs]

I guess I should have included the schematic....

[a90s2cs]

Being an optimist, I'm guessing no news is good news?

[sluckey]

Looks good to me.

[Ed_Chambley]

I looked at your Freehand Drawing.  Aldus Freehand!  I remember well.


The Schematic was Drawn by Mark Huss, so I would consider it verified.


Looking at you layout, it appears correct.  Took me a bit to find the second 10K dropping resistor.  layouts are tough to review, but I can follow the signal through from input to output and I did not see any component values out of line.


It looks sort of like everything I build.  What I mean is I use the Marshall layout on everything I scratch build.  It works!


I will say to make sure turn the laminates opposite on the transformers to insure no couling between each.

[a90s2cs]

Thanks for the input, very much appreciated.

I figured the Huss schematic was a good choice, and it included voltage readings. 

The position of everything on the diagram (except the board components) is arranged to make it as clear as possible (for me anyway) to see how everything is hooked up.  The transformers, caps and such are just lined up that way for illustration purposes.

[bnwitt]

Here's another layout just for your reference

[alerich]

The Schematic was Drawn by Mark Huss, so I would consider it verified.

Mark's schematic is correct. I built my JCM800 Mini using it and the amp fired up first time.

That's a pretty layout drawing. I am in awe of people who can build amps from layouts. It's like trying to figure out the guitar solo to Stairway To Heaven from tablature.

[a90s2cs]

I made some changes to the diagram for safety reasons....

Moved put the power switch before the fuse and made sure the "hot" side for both fuse holders was on the tip and not the ring.

I had it the way I did in the diagram for convenience then realized as I was mounting the switches in the chassis that if I followed my diagram the mains fuse holder would always be hot even when the switch was off, that's the opposite of good.  If someone were to replace the fuse while holding a guitar they could get a potentially lethal dose of voltage through the chest.

I also added 47k 2w resistors parallel to the standby switch for a "soft power-up".

I have joined the "standby switches aren't necessary" camp, yet want to include one to satisfy my nostalgia.