Before & After - my Marshall Super

pfflam

Member
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7,119
Many are sure to think this was useless and many will find it butchery.

I got a Marshall 40th Anniversary for cheap. I could not get it to sound great no matter what I tried -it sounded pretty good but not great

-so, being the 'unable-to-not-touch-a-single-piece-of-gear-I-own' kind of person I am, I decided to build a new circuit and replace the PCB circuit in the amp.

Here it is (and yes, so far it does sound far better - I won't be able to really try it out till I change the can caps)


Before:



After:





Anybody foolish enough to do this?

BTW: I learned a lot and had fun doing it . . . and want to make an amp with real point to point (no board just tag lines) as soon as I get a chance.
 

Knuckles

Member
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1,447
What kind of tonal changes did you work up? Still capable of the usual Marshall crunchy stuff or moving in a completely different direction?
 

pfflam

Member
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7,119
well . . I typed at 12pm and so everything I wrote got erased. Here goes again:

I'm not trying to get crunch, I want to get more warmth and a clean sound similar to Hendrix from the BBC recordings -it hinted at that tone before . . but only hinted

It was, before I changed it, hard and harsh, with very clangy upper-mids, even with the mid control all the way down and the presence down too.

It already sounds better, warmer and richer - I haven't been able to play it at any real volume yet, so I will have to wait

and also wait for the ANOS RFT EL34s coming, and new filter caps in the mail.
 

pfflam

Member
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7,119
At Volume, some problems start to appear: Rustling and instability (occasional crackles etc) and more importantly - it is simply not nearly as loud as it used to be.

I can now be in the same room with it at 9-volume, and it distorts earlier

BUT, it does bear that Drivin South tone under those problems.


I am thinking I will swap out the Carbon Comps for more reliable Carbon Films
 

8len8

Silver Supporting Member
Messages
13,581
It looks like you replaced some ceramic caps with electrolytics? Aren't electrolytics something to keep away from for more "vintage" sounds (I thought I heard that somewhere)?
 
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gulliver

Silver Supporting Member
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10,189
Gee ... I think you should of just built a whole new amp, you're 75% there. :YinYang
 

schmidlin

Member
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5,258
Well, to answer the OP's original question: yes. But I went from SS to tube.





Easy to mod on it now, too. :)
 

pfflam

Member
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7,119
Gee ... I think you should of just built a whole new amp, you're 75% there. :YinYang
That's next on the agenda: I have an old Organ chassis that has somewhat big iron - I want to try to make an 18-watt (or something like that) and do so without a board, just P2P with those ends (since I have a bunch laying around)

As for the electrolytics, wherever electrolytics are called for there they are. I only use one ceramic and that's on the treble-volume pot.

That ORANGE is super great: did you simply add places where tubes were called for, or did you rebuild the whole circuit?
 

drewl

Member
Messages
8,579
heh....this was a crappy sounding 70's solid state Marshall I gutted and turned into a 1987 footswitchable to a 2204 with two footswitchable post phase inverter master volumes.

It looked too cool and has a couple sweet old blackback celestions to let it stay a bad sounding solid state amp.






 

pfflam

Member
Messages
7,119
I love the look of that thing . . . must be great to get a fantastic tone out of it and startle expectations
 

Shiny_Beast

Gold Supporting Member
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10,354
I am thinking I will swap out the Carbon Comps for more reliable Carbon Films
I wouldn't worry too much about it, that's not the source of crackling. I think I saw another thread somewhere where you fixed this anyhow.

I say rock on! gut that sucker :) A PCB replacement is pretty non invasive, and now you hack up the circuit to your heart's content without worrying about damaging the original board.

hint, shared cathode on V1 :)
 

pfflam

Member
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7,119
Just thought I'd update: swapped out the 100k and the 220k and 82k 1watt carbon comps and all new filter caps and it sounds UNBELIEVABLE!!!

pics soon
 

pfflam

Member
Messages
7,119
Damn . . . another problem: now at volume I am getting very slow volume fluctuations, like its going in and out of phase on a cycle of some sort - very annoying: off to the amp tech area
 

big mike

Cathode biased
Platinum Supporting Member
Messages
12,993
Might have the leads of the OT reversed on the power tubes?

Looks good BTW. Was this a 1959SLP to start?
 

big mike

Cathode biased
Platinum Supporting Member
Messages
12,993
Try em the other way. The wires that go from the 220k bias resistors to the center two powertubes if it goes away it's fixed if it makes a godawful noise put t back the other way lol
 

DGDGBD

Member
Messages
6,985
Damn . . . another problem: now at volume I am getting very slow volume fluctuations, like its going in and out of phase on a cycle of some sort - very annoying: off to the amp tech area
check for a cold solder joint somewhere. i had a home built amp that would mysteriously lose a notch of volume especially at higher volumes and I finally found a cold solder joint that was the cause.

also, if it seems to be a regular cycle fluctuation, double check the new filter caps that were installed to make sure they're wired correctly and that they are not defective in some way.
 

pfflam

Member
Messages
7,119
check for a cold solder joint somewhere. i had a home built amp that would mysteriously lose a notch of volume especially at higher volumes and I finally found a cold solder joint that was the cause.

also, if it seems to be a regular cycle fluctuation, double check the new filter caps that were installed to make sure they're wired correctly and that they are not defective in some way.
Hi,

I did break the blue plastic wrap around one of the filter caps where the clamp fits around it: would that damage the Cap?
I put some glue on it thinking I might seal any flow should it actually be an issue
 

rastaman

Member
Messages
2,100
A member that used to be here had a JCM800 2203X RI and bought a metro kit and had an amp tech install it. That damn thing sounded awesome afterwards.
 




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