Metropoulos Forum

Hey Billy, just wanted to say "Thanks" for the beautiful layouts.

I'm currently restoring a 76 1986 for a friend, who wants it converted to a 1987 and ordered the board from George and found your layout super helpful.
So - as one of the 2k "hidden" downloaders: Thanks a million times.

Olaf ("Duesentrieb" in many forums)

my website

http://www.thinlizzy.de

No problem. Good luck with whatever you use them for.

Thanks for the layouts Dan. Very useful for my '69 1959 build

I must admit I'm not using George's kits, but his instructions and your layouts are very helpful to me.

Thank you Dan!

Hey Dan have you thought about doing a layout for a JTM 45 ???


Thanks Bro

You tottally Rock


The Layouts are so damm amaizing...Thank you once again for taking the time to do those up...

Next up, HiWatt DR-103 layout. I started it yesterday and hopefully I can finish it tonight. Itll be a mix between the Reeves layout and the Joyce layout.

Hey Dan have you thought about doing a layout for a JTM 45 ???

Yes and no. I did the 100s because at one time the forum was litered with repeat questions about wiring the filter cans up and the fuses etc... and then the power boards of the early amps etc... The MV's were just a huge mess of confusion. Then the 50s were popular demand 45s are even less complex then 50s and so people dont seem to need them. Im not against doing them though.

Billy Batz wrote:Next up, HiWatt DR-103 layout. I started it yesterday and hopefully I can finish it tonight. Itll be a mix between the Reeves layout and the Joyce layout.

Very cool Dan!

Dan,

while working alot with 2203 preamp lately i was reading a schematic and it doesnt seem to follow your layout as far as how V1a and V1B are wired. my questions are with where the input and volume go as well as the .68/2.7k - 10k.

the 2203 schematic dated 19-5-88 shows the input going to v1a and the preamp volume going to v1b as well as the cathode res/caps going to opposite sides.
any reason you chose a different way then the schematic shows?
i notice you have everything swaped but plates does it matter?

as im trying to better understand reading schematics this has me confused

thanks,
Mark

One thing is that it doesnt matter which triode you put the stages on. I could put stage one on V2a and it wouldnt effect anything other then opssibly being tougher to route wires. The important thing is that I believe though marshall did it both ways at some point, stage 1 was more often on V1b then V1a. In fact, you cant assume that just because the schematic file has the first gain stage physicaly first from left to right that that should mean its that way on the amp. Most schems arent labeled. The 81 factory schems dont have it labeled with stage 1 on V1a but they do have it on V1b. Not being a tech I cant validate which was done most often. I think it may be something as simple as when the amps changed to 800 series with a PCB change maybe they changed it then to ther way I have it.

As far as the cathodes I believe the very few schematics that are out there taht show the 10k on stage one are in fact wrong or possibly from very early 2203/4's. I dont know of any official schems that are that way. Actually I dont think there are any at all. The only place Ive seen that is the incorrect Metro CD layout.


Heres a few schems

http://www.drtube.com/schematics/marshall/78331-1.gif
http://www.drtube.com/schematics/marshall/jcm800pr.gif

You can see on the second factory schematic the triodes are clearly labeled the way I have it in my diagrams. With stage 1 and 2 labeled as V1b then V1a respectively. The 10k is always stage 2.

Hope that clears it up. Im not a tech so I had to rely on my own research.

Dan, thanks as always for cleary some thinsg up there!

woud ity be ok to put the 68k on the input on the 2203 on the board or should it go how you have it layed out? does it make a difference noise/osilation wise?

Mark

Yeah of coarse. Although from watching so many people here do 2203's then tweak them with more gain it seems the most practicle thing to do to keep the circuit stable is to have the 68k on the tube socket and use a sheilded wire from the input tip to the socket.

Billy Batz wrote:Yeah of coarse. Although from watching so many people here do 2203's then tweak them with more gain it seems the most practicle thing to do to keep the circuit stable is to have the 68k on the tube socket and use a sheilded wire from the input tip to the socket.

sounds good and thanks!

Hi Billy:

Your schematics have been downloaded 3033 time now... If we only had charged a couple of bucks for them...

Good to see there´s some use for them, and my webspace was just sitting there doing nothing.

Maybe they should be included on George´s site in the future. There seems to be a demand for high quality layouts.

He did have them on the CDs but they were old versions. Theres beena lot of revisions. Listed on the first page of this thread in case anyones wondering.

On some of the layouts there is a wire coming from the first mains filter cap ground that goes to a pair of turrets, connected to nothing. Is this for the 'snubber caps' to go across the board?

If so, is it like this?

turret furthest in top-left corner of board (with blue wire) connects to .22u cap, which connects to the furthest turret in the bottom-left corner.

turret next to that top-left turret (also with blue wire going to SB switch) connects to another .22u 630v cap, which connects to the turret next to the furthest turret in the bottom-left corner


ie. wire up the board like George's 69 PTP board in the store pics