Donor Amps

  • Thread starter Thread starter itsgoodnow
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itsgoodnow
Well-known member
Hey all,

I wanted to poll the audience. I had a 1975 JMP with 6550 tubes in it now. It was serviced and had a clean bill of health. Original Iron, new caps, new tubes, biased etc. It just sounds kind of underwhelming. Maybe I should have just had it converted to EL-34 at the time since my ear favors those. Anyway, I bought the amp as a modding platform and I was wondering if you all thought the better the donor was in stock configuration that the mod would turn out? Or does it not matter much. Thanks.
 


I hear good things about this and you wouldn't have to send off your amp somewhere and hope it comes back.
 
shar-vell Dan said:


I hear good things about this and you wouldn't have to send off your amp somewhere and hope it comes back.
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I appreciate it. That's definitely on the list of things to try. This one is headed to a very reputable modder/manufacturer so luckily I feel pretty good about it.
 
IME the donor amp is super important to how potentially good sounding it comes out modded even with Hermansson’s. It can very much make or break the result IME and imho not worth it if the amp doesn’t sound good to me begin with. It may still sound great after the mod, but from what I’ve tried would’ve had the potential to be that much better with a better sounding amp from the get go

It’s kind of like if me or Ronnie Coleman took the same exact performance enhancing drugs we would still not come out the same at all as bodybuilders lol because I am not the best donor person to be modded into a great bodybuilder so to speak with my goofy analogy lol. I’d be like a 5w champ and Ronnie Coleman would be a Hiwatt DR103 or Megalith Beta as mod platforms
 
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ClintN667 said:
Man.. I wouldn't mod that honestly. Those are getting harder to find I would get a hot mod.
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Yeah I definitely understand. The amp was purchased to be a complete preamp rebuild so the hot mod wouldn't really take me to where i want to go--if that makes sense. Realistically I am just wondering if a donor that (to me) sounds a little lackluster would hold the mod back.
 
Are you going to mod it yourself? If you are going to ship it off I would recommend send it to someone who can tweak it if needed. I sent off a quick rod one time cause I just wanted a little more saturation got it back an immediately sold it. So now I'm more picky on who I get to mod
 
Honestly in 2024 people have predetermined notions of what a Marshall should sound like and it’s normally modded that’s on records that kick ass and not bone stock. As much to the wayside guitar playing is going I don’t think it matters anymore. Mod as you wish. It’s easier to get stock Marshall tones now from any source you can imagine anyway. The mod you’ll have built won’t exist in the world until the circuit is complete.

As others have said a good sounding donor helps with getting a good sounding amp afterwards.
 
I would also add the EL34s. They just sound better and its easier to find replacements.

I would also get it modded if you can get @Monomyth or @RedPlated or someone good like that to do it.

You can certainly stack boosts and get them sounding fine stock, but I would get it modded.
 
DanTravis62 said:
I would also add the EL34s. They just sound better and its easier to find replacements.

I would also get it modded if you can get @Monomyth or @RedPlated or someone good like that to do it.

You can certainly stack boosts and get them sounding fine stock, but I would get it modded.
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Thanks man. Hilariously your recommendations are sport on for my taste. I’m fortunate enough to have a MOAB + super lead and a skeleton key modded 2203. This will be something to mix it up even more. I agree with you. I keep a stock 2203. The rest all get modded.
 
itsgoodnow said:
Thanks man. Hilariously your recommendations are sport on for my taste. I’m fortunate enough to have a MOAB + super lead and a skeleton key modded 2203. This will be something to mix it up even more. I agree with you. I keep a stock 2203. The rest all get modded.
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If you already have those, maybe hopkins or hermannsson? Eddy Lenz?

Shit, get GLP to do it. Or dawn of dreams. Or Fusionbear.

Or maybe find someone to do a CCV or Atomica mod?

There's a million options, and IMO they would all be interesting.
 
For sure. I have 2 Hermanssons also. I’m going to reach out to some of them here shortly. I just want to make sure this Marshall doesn’t blow. But I think the issue is there may some mods internally that sound bad. Despite the tech saying it’s stock on the circuit.

Also I see the output transformer has a small dent in the corner. Which I know nothing about if that could affect tone
 
in my experience, the condition of the donor is important. if it’s serviced, safe to current standards, clean and reliable then it helps the modder focus on the rebuild vs servicing the amp.

for mods involving major rebuilds, I wouldn’t care about sound as stock
 
I'm in the same situation...I also have an original JMP 75 that sounds bad.
I also bought it to send it to a "very reputable modder/manufacturer"..
But I have decided to give it a try and try to make it sound as it should...maybe there is some component out of range that makes it sound very bass flubby.
Instead I will modify a 74 jmp50w already previously modified.
 
Not to deviate off topic too far but do you guys notice that it’s really hard to find a great sounding mid to late 70’s stock Marshall? Were those the shit years or something? I’ve read a couple of times on a few forums there were a lot of duds out there but no specific year range was ever disclosed. I’ve ran into 1 good one the past 6 years when I was searching for one.
 
PurityS.L.G said:
Not to deviate off topic too far but do you guys notice that it’s really hard to find a great sounding mid to late 70’s stock Marshall? Were those the shit years or something? I’ve read a couple of times on a few forums there were a lot of duds out there but no specific year range was ever disclosed. I’ve ran into 1 good one the past 6 years when I was searching for one.
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I have a 1978 stock 2203 that sounds amazing and I’ll never mod . They are out there man
 
haven’t had many around at the same time to tell good from less good. i had a ‘81 that was serviced by Marshall right before i bought it and it sounded and behaved like a new amp.

my issue with old JMPs, although my fav, is where they were stored in the last 40-50
years. That otherwise brilliant ‘81 was exposed to moisture and smelled of damp and mouldy wood..
for that reason alone I now only buy reissues as donors, typically 1959s which can be had at almost half the price of a decent JMP in the UK used market, are up to current electrical stds, have a loop so I don’t need to pay the modder to add one and are made in the same place as the old ones.
 







I cant tell you the litany of BS forum folks [not just this one] i had to filter thru trying to formulate the right builder.
"Never drill holes on a Marshall" and "never use a boost with a modded amp. Tons of shit people were just making up
Didn't mean shit.
Its your amp customize it how you like. Just don't send it to mark scammeron or youll never see it again.
Party on Wayne ...
 
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DanTravis62 said:
If you already have those, maybe hopkins or hermannsson? Eddy Lenz?

Shit, get GLP to do it. Or dawn of dreams. Or Fusionbear.

Or maybe find someone to do a CCV or Atomica mod?

There's a million options, and IMO they would all be interesting.
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Hi Dan, who is GLP or dawn of dreams or Fusionbear? are those guys amp modders? I have a marshall 1959 that I would like the ocean mod or this mod:

 
MetalJim said:
Hi Dan, who is GLP or dawn of dreams or Fusionbear? are those guys amp modders? I have a marshall 1959 that I would like the ocean mod or this mod:

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GLP is a user on here. Dawn of dreams as well. Fusionbear is a member but I believe he isn't doing mods. All are great modders. Coincidentally, the amp you posted was cloned (or close to it), by Dave Friedman and is for sale now here:

https://www.rig-talk.com/forum/thre...nd-wired-w-friedman-jose.308451/#post-3939576
 
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