1974 marshall 1987 w/turret board?

Rhino x3

Member
Messages
36
Calling all Marshall experts...I recently purchased a beat up1974 50 watt Marshall, date code F, March 1974 tag I assumed it was pcb but this is what I found inside. Does this look stock? Also, this washer was floating around inside, what the heck is it? Is it the wafer from a pot? Thanks, Mark
 

Dan40

Silver Supporting Member
Messages
1,382
That board is not original to the amp. I believe that is a Hoffman board that someone installed in the amp.
 

Rhino x3

Member
Messages
36
Cool, thanks, the amp sounds fantastic I was just curious as that seemed a bit late (based on my very limited knowledge of Marshalls) to be non-pcb, I'm pretty much an agnostic in the pcb vs ptp debate.
 

TimmyP

Member
Messages
2,485
PCBs are great - until you want to fix or mod something, then they are a PITA (unless the components are on the foil side like BGW used to do in their SS amps).
 

Blue Strat

Member
Messages
30,180
Pretty sure the original probably had a turret board if the amp is a 1974. I guess the question is, did you pay the price for an original amp...or an amp with a replaced board?
 

zenas

Member
Messages
8,756
I've got a 74 1987 Canadian spec amp. PCB that differs from every other one I've seen in a couple of areas. Also had some bad trace I repaired and couple previously repaired.
Based on that I can see where one might just go with a new board, I would've probably reused the mustard caps though.
 

MKB

Gold Supporting Member
Messages
8,366
I'd have to respectfully disagree on the early 70's Marshall PCBs being good quality. I have seen many and owned a few that had the cheap single sided PCBs with no solder mask, and they caused issues from time to time. Those heavy components hanging from traces with no through hole PCB support was not good. I have significantly improved the tone of one 70s Marshall NMV by simply cleaning the gunk off of the trace side of the PCB. The worst were the ones with the push on terminals, those often worked loose. I can easily see where someone would be persuaded to replace the PCB in their amp with a turret board, especially if a few components got cooked on the original PCB.

Even some of the newer Marshalls have poor quality/poorly designed PCBs, the one in my old Haze was not a good layout at all. That amp developed some leakage paths that caused bad noise issues.

I am not against PCB's, I believe a well designed PCB is the best way to go for multiple reasons (and I have been designing PCBs for test equipment for almost 30 years). Marshall just doesn't do a great job with PCB design sometimes.
 

Rhino x3

Member
Messages
36
Thanks for the replies, it's so cool to get definative answers about things that are kind of a mystery to me.I got into this one super cheap so I'm not worried about value. It sounds fantastic and that's my biggest concern. Zenas, I have a Canadian jcm800 and it has some pretty weird stuff going on inside.
 

zenas

Member
Messages
8,756
MKB that sounds like the board in my amp. The push on terminal thing. Most of those were solder up at some point.
Must have been a nightmare keeping it running, probably why it ended up in North Dakota where I found it in a pawn shop. Best part was when I plugged it in and the shop went dark. lol
 

gldtp99

Member
Messages
3,828
Yes, replacement Hoffman layout turret board----- populated with modern components---- It most likely sounds good----- I agree that the loose washer is a retainer for the original power lamp.
I got an inop Marshall 4010 (50 watt JCM 800 1x12 combo) several years ago---- it had been poorly modded, I got it back in working order with some more mods---- I used it for a while and tried a series of other mods--- by this time the original PCB was in bad shape so I rebuilt it (near stock this time) with a new turret board (and Metro FX Loop and Lar/Mar PPIMV)----- it sits in my living room and I use it to write music with---- I usually have the Preamp and pre-PI cranked up and the PPIMV turned down to very low volume---- I can get a heavily driven tone at TV level volume----- and my neighbors don't call the cops on me:

 

Rhino x3

Member
Messages
36
The power lamp washer makes sense because when I got it the lamp base was broken and I epoxied it back together and couldn'the get it to stay in place so I put a dab of silicone on it. I forgot to mention that the amp has something that puts it heads and shoulders above all other Marshalls....
Behold!
 




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