18W'ish Marshall Style Amp Build.

[GoldenVulture]

Decide on a power supply section and an output section[ including P.I. ] and take it from there.
Get all your parts out for that and you'll probably field ideas on where to go on the way.
Build you power supply and then your out put section. Your power supply will probably be able to cover many pre-amp configurations. They don't vary a lot when it comes to power to drive them.

[karpathion]

Okay.

Because of my OT, it will have to be an 18W, dual EL-84, push/pull, Class A or A/B amp. I want class A, just because it's period correct, and part of the tone. I also want the Marshall style, PI trick. That, and the tone stack, are what makes that Marshall style tone, in my opinion. I learned that from the Windsor mod.

Power supply, should be able to handle 1 pair of 84s, a PI, 3 preamp valves, and one rectumfryer valve. I'd kind of like it a bit oversized, just because I want's its!

I can pull some schematics in the morning as reference.

[GoldenVulture]

There's not a lot of diff in the P.I. design in Marshals. It's similar to many others. The big difference is using that Cathode Follower [ that's what it's called ] configuration in the pre-amp. It seems to make the pre-amp turbo driven.
They put the tone stack between that and the P.I.

[karpathion]

I just call it the PI trick because it took me a minute to understand it on that Windsor mod. I though it was a cool trick then. It is that PI setup and tone stack that makes the bulk of that Marshall vibe, to me.

I'm still digging in schematics, but I think it's starting to come together. I should have something worked up soon, schematic wise anyways.

[karpathion]

Ended up getting a little bit done this morning. I finished disassembling the chassis, sanded all the old paint off with a palm sander and 80 grit and got 2 two good coats of Dupli-Color, high heat, engine primer on it. There would be 1 or 2 more coats, but I only had a half of a can left from my engine build. That stuff works great on anything. Highly recommended primer for anything metal. I have to kill a couple of hours before that stuff cures fully. Then, I can go back and wet sand with a 400 grit paper, and get it painted.

There is a can of Mopar Blue, engine paint in the garage that is calling my name on this chassis, but that may not look as good as I think it will. I also have a can of VHT, gloss black, engine paint, and a can of Matte black Dupli-Color, engine paint. The matte seems to be the ticket on this one. 2 good coats with sanding in between should get it done nicely.



Yeah, I know. I need to clean up my damn garage, and blow off the driveway. I've been distracted lately.

[karpathion]

And as usual, my dumbass got a little ahead of myself. I forgot to drill out the holes for the pots.  :scratchch:

Oh well. I'll either drill them later with a step down bit, very carefully, or use mini pots. It's not that big of a deal, I guess.

[karpathion]

I had to try it, just to see what it would look like.



Gonna let that dry for a couple of hours and have another once over, but it's not looking very promising. The blue just doesn't do it for me. I'm thinking matte black, it will be. If there were more metal flake or pearl in it, it probably wouldn't be so bad.

[GoldenVulture]

And as usual, my dumbass got a little ahead of myself. I forgot to drill out the holes for the pots.  :scratchch:

Oh well. I'll either drill them later with a step down bit, very carefully, or use mini pots. It's not that big of a deal, I guess.

I ended up drilling some pot holes way after doing the chassis painting job when I added the second channel to my build.. No problems in doing so.

[GoldenVulture]

I had to try it, just to see what it would look like.



Gonna let that dry for a couple of hours and have another once over, but it's not looking very promising. The blue just doesn't do it for me. I'm thinking matte black, it will be. If there were more metal flake or pearl in it, it probably wouldn't be so bad.

I sort of like it and I'm not a fan of Blue , so there you go. Black works well, just take a look at mine.
Plenty of space on that chassis.

[karpathion]

The blue had to go. It was just way too bright, and would have stuck out like a sore thumb.

I ended up putting 3 coats of matte black on it, while drinking 3 beers, and it looked really good. Then, I drank a 4th beer, and had a flashback to painting model cars as a kid. I took the blue and sprayed it up in the air, and the blue, mist the black. It's how I used to create my colors for models. It looked pretty damn good like that, but I just couldn't stop. Found a full can of Kamar Varnish, and for some reason, thought it would be a good idea to cover the painted chassis with. It's been 3 days, and that stuff still hasn't crisped up yet. It still feels rubbery and a little soft, and I don't think that varnish is supposed to harden up like that.

So, I probably made a big mistake, but it's to late to worry about it now. I just hope it doesn't heat up and melt, or catch fire.