MetroAmp treasure chest

[RetiredUnit1]

Probably a lot of people here have heard of 'Velvet George' owner of Metropolis amplifiers. One of the things that good ol' George has done is to release a large number of his classic amplifier layouts and modifications to those layouts to his forum, and they are now available on a google drive. You have to download it in Zip format, and then unzip to your drive and there's literally a treasure chest of Marshall amplifier designs to do with as you please.

Apparently these were originally released on his forum, but some misguided miscreant hacked and destroyed the database. Kids....

Fortunately for posterity, a fellow whose initials are SDM gathered his copies together and shared them with the world. (EDITED: Actually I think that's George's real initials, lol, I don't know for sure)

I've been making a layout for my own JCM800 2203 100w and was having a hard time finding anything other than modified versions. I wanted the original so I can modify, lol. I found a discussion of this on his forum yesterday and after unzipping literally came to a skidding halt on my chin as it hit the floor!!!


Here's the link:

Google Drive: Sign-in

Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).

drive.google.com

And of course the 2203 layout I so desperately was searching for, color me HAPPY!

 

[szukalski]

You are a legend! Thanks

 

[AgAuthority]

Grabbed it all, maybe be the motivation to get back to my 2203 project……probably not….

Ag

 

[Feral Feline]

Cheers!
Many thankages for that linkeroo!

 

[RetiredUnit1]

Grabbed it all, maybe be the motivation to get back to my 2203 project……probably not….

Ag

It's been on my 'bucket list' (do it before I kick the bucket) for a LOOOONG time. As I'm 67 I am hot on that list. I'm modifying the layout to work with my 'made for pcb' nos mustard caps, as I have over 600 of them I got on sale when the economy in Greece hit the skids back around Y2K. This is what I have so far, I had to substantially change the bias so I could adjust the two sides independently. The stock layout has the adjustment on the grounding side, too late to be independent. If I put another adjustment on that it would just divide the resistance in half..... And I have a bunch of radial lead .68uf's too.....

 

[HamishR]

I miss Metroamp's selection of goodies. Valvestorm has kinda taken over the parts business but you have to remember to wake them up before ordering from them. Then they're great!

I haven't built a 2203 but have built my share of 2204s and 1987s. I love those amps. They're great fun to build, too. You have enough space to do everything and they're well laid out.

 

[RetiredUnit1]

I miss Metroamp's selection of goodies. Valvestorm has kinda taken over the parts business but you have to remember to wake them up before ordering from them. Then they're great!

I haven't built a 2203 but have built my share of 2204s and 1987s. I love those amps. They're great fun to build, too. You have enough space to do everything and they're well laid out.

I saw Valvestorm when I was searching for 2203 Chassis. Based on the prices, I've decided to just build my own. I'm going to cut the size down to 24" wide while I'm at it 'cuz of all the empty space. I have a metal shop willing to take my .dxf's and turn them into holes in a sheet of aluminum for a reasonable price, and I have a sheet metal bending brake, and a brazing setup.

A couple pics of my model 1987 I modified the layout to make use of my made for pcb short lead .022 mustards.... And yes, I have a plexi glass circuit board on my plexi, lol.....

 

[HamishR]

Wow - the chassis and everything looks great! I used to get someone local to form chassis for me but it was a pain getting faceplates made to fit. I might possibly have left a little more space between the PT and OT but I know how tricky the spacing of this suff is. They're oriented the right way so any induced hum is probably minimal. And I do like how Mercury finish their transformers. That hammertone looks killer.

 

[RetiredUnit1]

Wow - the chassis and everything looks great! I used to get someone local to form chassis for me but it was a pain getting faceplates made to fit. I might possibly have left a little more space between the PT and OT but I know how tricky the spacing of this suff is. They're oriented the right way so any induced hum is probably minimal. And I do like how Mercury finish their transformers. That hammertone looks killer.

It's the stock JTM45 spacing, will never do that again! Like building a ship in a bottle. There is no hum at all, zip! I am shortening the chassis on the 2203, but I'm going with 8" wide instead of 6-ish....