My Marshall Conversion From PCB To PTP

STRATDELUXER97

Stratoblaster Tone Meister
I finally got around to converting it over to PTP.....It's a 1973 50 watt 1987 head....Sounds really great and it'll be better once these Sozo caps break in all the way...A few mods in there also! As always! :27: :chairfall :banana:

In my opinion metal film resistors "don't" make an amp bright and sterile if it's setup right and you know what you're doing....I'm waiting for the "Why no carbon comps"? Cause they add extra noise and hiss that I don't need and I can do without the drift in values!....LOL I will never have to deal with that stupid PCB board ever again!

Waiting on the 2 extra .022 Sozo caps to arrive to replace the Orange Drops,unless I want to go to the Sozo .1 caps that I do have? I prefer .022 values here though...

I snuck in some cool V2 mods,and a resonance control,and a few changes overall on the board for the cathodes on V1...Basically what I had before,but with newer components and the PTP board...The amp sounded great before,but I much prefer the PTP board.No extra gain stages added to the amp either! LOL

Just need to mess with some different tubes for V2 and V3....I think I'm going to move the PT primary wiring to the underside of the board,as I think it'll look better?

I've also lowered the pf cap across the Normal Channel's volume pot and I'm working on a different volume pot bright cap for the Bright channel,as I don't like the .005 these days and prefer that channel alot warmer....I don't crank the amp to 10 and until I get another attenuator,I need to maybe remove this cap or lower it "alot"?



19873.jpg


All Sozo Caps Today! Much Much Smaller Bright Caps Across Volume Controls Also.
AMP1.jpg


Here's the insides of an incredible old HiWatt Amp.....Most of your boutique builders were bit by the clean and neat insides of this amp....The first time I saw the insides of one of these amps,I almost pi$$ed myself....I consider my amp sloppy compared to all the right angles and neatness inside of a Hiwatt amp!
DR103Guts.jpg
 
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Re: My Marshall Conversion From PCB To PTP

Nice work, bro. :fing2:

Did you write inside the chasis the date of the conversion? Might be a nice touch in case your forget down the road.

I agree on the resistors. Those were used back in the day because that's what was available. Too much mojo tossed around with stuff like that.

I know you don't normally do them, but dammit, I want clips. :laugh2:
 
Re: My Marshall Conversion From PCB To PTP

ErikH said:
Nice work, bro. :fing2:

Did you write inside the chasis the date of the conversion? Might be a nice touch in case your forget down the road.

I agree on the resistors. Those were used back in the day because that's what was available. Too much mojo tossed around with stuff like that.

I know you don't normally do them, but dammit, I want clips. :laugh2:

I have all of my current voltages written down and I wrote a small date on the PTP board....I'm very anal like that as you know!

I don't do clips! Too much hassle for me right now! :)
 
Re: My Marshall Conversion From PCB To PTP

Man way to go John!!!! Wish i knew how to work on amps like that! My early 80's 800 head needs lots of tweeking
 
Re: My Marshall Conversion From PCB To PTP

Looks like great work?
But isn't it a different amp now ;)
 
Re: My Marshall Conversion From PCB To PTP

STRATDELUXER97 said:
I have all of my current voltages written down and I wrote a small date on the PTP board....I'm very anal like that as you know!
Yes, I know. That's cool that you are that way though with this stuff. It keeps things accurate and in check so to speak. What kind of mods did you add in?

I don't do clips! Too much hassle for me right now! :)
Awww, c'mon, mang!!! We need to hear this beast. :)
 
Re: My Marshall Conversion From PCB To PTP

Marcel said:
Looks like great work?
But isn't it a different amp now ;)

It sounds better with the new components yep,but it's basically the board that's really different....I Like the Sozo caps alot,but they have about a 100 hour break in period before they get really sweet from what others say about them?
 
Re: My Marshall Conversion From PCB To PTP

That's gorgeous looking work John!

Be interested in hearing your thoughts on it after the break-in period and you really get a chance to have it up and running for awhile.
 
Re: My Marshall Conversion From PCB To PTP

Very sweet work, so clean... your mom would be proud! ;)
 
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Re: My Marshall Conversion From PCB To PTP

Yeah it's 100 hour break in period, but after about 20 hours the caps are mostly formed. Pull your power tubes out and run a CD through the amp tonight while you're asleep (with the volume controls up), that should burn in the caps pretty well.

The amp looks great, I thought you'd like those caps. Right now those Sozo's are good enough not to warrant me spending a lot more on changing them out with the handmade ones, even though I'm sure the handmade ones sound even better.

I quite like having .1uF caps at the phase inverter, I can imagine they'd sound good with a bright '73 circuit.
 
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Re: My Marshall Conversion From PCB To PTP

Dang John. Thats sweet looking. Is this something you did as a result of getting that amp book at the show? Or was this something you were working on before?

Very nice. :)

Artie

(Say "hey" to Steve for me.)
 
Re: My Marshall Conversion From PCB To PTP

So that's why you've been away. I wish I knew about that stuff. Sounds like a rewarding type of hobby/pastime.
 
Re: My Marshall Conversion From PCB To PTP

STRATDELUXER97 said:
I have all of my current voltages written down and I wrote a small date on the PTP board....I'm very anal like that as you know!

I don't do clips! Too much hassle for me right now! :)
Looks real nice John. That's a nice clean layout!! I like the idea of the 2 1ohm Bias resistors on the board. As far as your voltages go, Would you mind posting them or PM them to me? I'd like to compare to my 2204 PTP.:) I'm having some oscillation problems. I have 1.5k grid stoppers on Pins 5 now
(as per George at metro) I just ordered 5.6k to replace them.(Hope that helps) I have to keep the presence knob real low. ( I got to get some aluminum sheeting for my case to. Once again... LOOK'IN GOOD.:D
 
Re: My Marshall Conversion From PCB To PTP

kmcguitars said:
Looks real nice John. That's a nice clean layout!! I like the idea of the 2 1ohm Bias resistors on the board. As far as your voltages go, Would you mind posting them or PM them to me? I'd like to compare to my 2204 PTP.:) I'm having some oscillation problems. I have 1.5k grid stoppers on Pins 5 now
(as per George at metro) I just ordered 5.6k to replace them.(Hope that helps) I have to keep the presence knob real low. ( I got to get some aluminum sheeting for my case to. Once again... LOOK'IN GOOD.:D

I could,but the 2 amps are different,plus the 1987 uses the 1202-164 PT and your's probably has the 1202-324 or whatever the number is?

I'm still tweakin on the dropping resistors to get my overall voltages where I want them....
 
Re: My Marshall Conversion From PCB To PTP

Yes, I know. That's cool that you are that way though with this stuff. It keeps things accurate and in check so to speak. What kind of mods did you add in?

Selectable switch on V2s cathodes to dial in different cap values,or no cap across the 820 resistor....A resonance pot and selectable "slope resistor" pot......Plus some "stability" things...LOL
 
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