Installing Metro50 board in a stock '79 Marshall; good idea?

[JDW3]

My '79 2004 Marshall has not sounded right in many years. I quit using it but recently played through a DSL100, and loved the overdriven tones. So, why casn't my old Marshall sound like this? Is it possible?

Will I kill the resale?

The Marshall currently needs work anyway, and I've had techs "fix" it too many times.

Will I be able to get those killer metal tones with a new board?

[neikeel]

Post some pics, and a list of the valves you have tried, to show if it has stock transformers and board in case someone has modded it and wrecked its tone.

In general I would not meddle but if it sounds bad and you know what you want to achieve someone here will help

[JDW3]

It has stock transformers. Years ago the amp was biased way too hot and it burned the output tube sockets. I had that fixed but do you think the transformers could have been harmed? I ended up playing it for years afterwards. The board looks stock. I'll see if I can get some pics of it.

The overdrive is just really grainy. I had a guy work on it the last time and it came back so damn shrill and trebly it was unusable. I'm just tired of having to have it looked at.

I was also wondering if a replacement board would sound better than the stock board, with all the talk of mustard caps and A-B resistors.

[Mars Hall]

Do you know what the tech did to the amp to fix it? Did he retube and or recap the amp? Before you decide to radically mod the amp, make sure you've exhausted all other avenues. So was there a time you enjoyed the tone of this amp?

[JDW3]

I used to really enjoy it back in the '80s! Had a huge fat overdrive. It's more buzzy now, with a grainyness I just can't dial out. I've had at least 4 different techs work on it. But as I've found out, many don't have ears. They have sine waves and such.

Seriously, the amp was decent for awhile. The main culprit right now is a hum which sounded like a ground. I replaced all the tubes. The other major problem is the shrillness.

I could just sell the amp. But I built a Metro 50 and know that I could drop a new board in the Marshall with ease. Or just build a new one right?

My Marshall has never been recapped. Has good Siemans power tubes. It has the chicklet style caps on the board, so I figured why not just replace everything with "known" quality caps and resistors? Every time I play through a JCM800 or similar I wish mine sounded as good.

[Mars Hall]

My Marshall has never been recapped. Has good Siemans power tubes. It has the chicklet style caps on the board, so I figured why not just replace everything with "known" quality caps and resistors? Every time I play through a JCM800 or similar I wish mine sounded as good.

I bet if you replace the caps it'll come back to life. Filter caps are generally good for about 10 years, yours are over 30. I think it will be worth the few bucks, just to find out, before you gut the amp. A thin sounding amp is considered one of the symptoms of caps that are too old. The internals of a cap, are very similar to a battery, it's a chemical reaction that creates the capcitance. It's not a situation of "if" they will fail, but of "when" will they fail.

Those "chicklet style" caps are nothing to turn your nose up at either. One of my favorite Marshall tones came from a 78 50 watt head that belongs to a friend of mine.

[JDW3]

Yeah, you're probably right. I should get it back on the bench. I get involved with too many things at once. I have a little el-84 amp here; can't decide if I should cascade the input haha.

[Mars Hall]

Yeah, you're probably right. I should get it back on the bench. I get involved with too many things at once. I have a little el-84 amp here; can't decide if I should cascade the input haha.

It's ok, we're all tone junkies at heart. Don't worry, there is NO cure.

[Doug H]

If all that fails I'd suspect the OT.

[JDW3]

Like I said, I had suspicion the OT could have been overloaded when it was biased wrong. I was gigging it with the tubes red hot. I didn't know any better.

It's the one amp I have I've never tried to work on. I guess because of the PC board. I'll give it another look.