Before & After - my Marshall Super

[pfflam]

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]

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]

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]

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]

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)?

 

[gulliver]

Gee ... I think you should of just built a whole new amp, you're 75% there.

 

[schmidlin]

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

Easy to mod on it now, too.

 

[pfflam]

Gee ... I think you should of just built a whole new amp, you're 75% there.

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]

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]

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

 

[Shiny_Beast]

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]

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]

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]

Might have the leads of the OT reversed on the power tubes?

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

 

[pfflam]

Yes it was a 1959SLP

How do I tell about the leads?

 

[big mike]

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

 

[edge11]

How much do you want for the pcb mate?

 

[DGDGBD]

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]

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]

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.