Grateful Dead Music Forum

Hey guys,
Based on the photos, how clean and original do these two MC50 circuits look? (pics below)
If you had to keep only one of them, which one would it be?
And is there any real advantage to running two MC50s in stereo instead of a MC250?
Finally, are there any common mods people do to get even closer to the sound of his MC2300 when using a guitar?

You can't tell anything meaningful from the pictures. What is important is that everything is working right, not that it looks right or original. I would test any electrolytics over 10 years old and be prepared to replace any that are out of spec. Everything else should hold up if they weren't exposed to too much moisture which can cause the CC resistors to drift. This is a job for an experienced tech who knows these amps and who can go through them to test and fix to get them into prime working shape for another decade plus.

2x MC50 may or may not be easier to transport. Could be worse for some. Sound differences are minimal in hifi settings and not worth worrying about in live guitar use.

The only mods I would do to a McIntosh...
Add 1/4 input and output jacks (can replace RCA if you prefer) [not necessary but may help simplify your bag of cables/converters if gigging it]
Add a power switch [not necessary if you use with a power strip with switch and light]
Add a power LED

Nothing else is going to make it sound more like a 2300 but it's not needed anyway. My personal 2100 currently has no mods. I use bare end to 1/4 speaker cables and RCA to 1/4" adapters for the input. The RCA adapters have been a weak link so I might drill a couple holes to add the 1/4" inputs, but I am also considering making high quality 1/4" to RCA cables and ditching adapters. In other words, you don't really need to change anything on the amps themselves.

Hey Chocol8,

Thanks for your detailed reply man, much appreciated!
When you say “I would test any electrolytics over 10 years old and be prepared to replace any that are out of spec,” do you recommend doing that even if the amps seem to be working well or should I do it anyway? And how much fees should I expect if some of them need to be replaced?

Also, when performing a sound test to confirm everything is functioning properly, is it important to test at very high (stage-level) volume? For example, with older speakers, they can sound fine at low volume but reveal issues like voice coil rub at higher levels.

I’m asking because I live in an apartment with neighbors, so pushing the volume too high isn’t easy to do.

gd6595 wrote: ↑Tue Mar 17, 2026 3:56 am Hey Chocol8,

Thanks for your detailed reply man, much appreciated!
When you say “I would test any electrolytics over 10 years old and be prepared to replace any that are out of spec,” do you recommend doing that even if the amps seem to be working well or should I do it anyway? And how much fees should I expect if some of them need to be replaced?

Also, when performing a sound test to confirm everything is functioning properly, is it important to test at very high (stage-level) volume? For example, with older speakers, they can sound fine at low volume but reveal issues like voice coil rub at higher levels.

I’m asking because I live in an apartment with neighbors, so pushing the volume too high isn’t easy to do.

What to do with electrolytic is a similar situation to old tube amps. You can test and replace as needed, replace all of them proactively, or keep playing until something fails. They will fail eventually but you really don't know when. I recently purchased and restored a 1961 Brown Fender where some of the caps had failed and were replaced in 1972 (11 years old) and some still tested OK in 2026 (65 years!). All of the caps put in in 1972 still tested good (54 years). So, figuring 10-80 years, it's a crap shoot! After some deliberating I ended up replacing them all on that amp as I am using it a lot and the OT is nearly irreplaceable. My 2100 has a mix of original and replaced caps and I will only replace any when there is an issue.

If I owned the MC50's and was planning to keep them both, I probably wouldn't replace them unless there was an issue, but then I have (too many) other power amp options to use when one is down and I can replace them myself whenever needed. If you are looking to keep one and sell the other, and reliability for the next 10-30 years is important, then it might make sense to have someone go through them both and maybe get one fully serviced and sell the other. The big cans on the outside and the big silver one inside will be the most expensive, but labor will add up depending on what kind of techs you have in your area.

As for testing, a listening test is OK, and in that case hitting them hard and loud will expose failing but not failed main filter caps that might be OK at lower loads. Personally, I would test using a capacitance meter and not just listen(because I can), and that's what a tech should do.

FWIW, I can't see the big external cans, but all the electrolytic caps I can see on both amps do look like they have been replaced, but I can't see date codes to know when. Also, the big orange caps are not original and not supposed to be in that location and there are two resistors missing from those boards (likely relocated with smaller modern resistors) which suggests both amps were serviced by the same tech at some point. So, you may be good to go already. Do you know the history of them? When they were last serviced?

Do they both sound good at apartment volumes? Do they sound the same? Are you going to be gigging them with/without a backup? Do you need the money from selling one? Are there any techs with McIntosh experience near you? These are questions that should guide you on what to do.

I see, thanks so much for all these information!

To answer your questions:

I haven’t bought them yet—I’m supposed to meet the seller this week.

He told me he bought them used from someone else about 5 years ago, and that the previous owner only replaced some capacitors, nothing major or critical.

He also added a blue power LED on both units, like the mod you mentioned.

The main issue is that he lives very far away, so we’re planning to meet halfway, and I won’t be able to test them in person. He said he’ll send me a video today or tomorrow with a sound test to show they’re working. He seems honest and has a 5-star rating on eBay with good reviews (though not a huge number of them).

It’s not possible for me to go to his place since I don’t drive and he lives in a rural area. On his side, he doesn’t want to come all the way to me, which I understand since he’s already making a big effort. So unfortunately, I won’t be able to test them beforehand, which makes me a bit worried.

He also doesn’t want to sell them separately—I originally only wanted one—but I could use the second one as a backup or for a hi-fi setup.

I’m in France, and they’re harder to find here and more expensive than in the US, so I don’t want to miss this opportunity to finally own one. They’re not cheap, but the price seems reasonable for the European market, especially considering their clean condition.

I just hope he’s honest, and that when I finally get to test them at home (at low to moderate volume), everything works as expected.

Here is a link of the video he just sent it to me. What do you think?
https://drive.google.com/file/d/1nnQGaW ... sp=sharing

Chocol8 wrote: ↑Tue Mar 17, 2026 8:41 am

gd6595 wrote: ↑Tue Mar 17, 2026 3:56 am Hey Chocol8,

Thanks for your detailed reply man, much appreciated!
When you say “I would test any electrolytics over 10 years old and be prepared to replace any that are out of spec,” do you recommend doing that even if the amps seem to be working well or should I do it anyway? And how much fees should I expect if some of them need to be replaced?

Also, when performing a sound test to confirm everything is functioning properly, is it important to test at very high (stage-level) volume? For example, with older speakers, they can sound fine at low volume but reveal issues like voice coil rub at higher levels.

I’m asking because I live in an apartment with neighbors, so pushing the volume too high isn’t easy to do.

What to do with electrolytic is a similar situation to old tube amps. You can test and replace as needed, replace all of them proactively, or keep playing until something fails. They will fail eventually but you really don't know when. I recently purchased and restored a 1961 Brown Fender where some of the caps had failed and were replaced in 1972 (11 years old) and some still tested OK in 2026 (65 years!). All of the caps put in in 1972 still tested good (54 years). So, figuring 10-80 years, it's a crap shoot! After some deliberating I ended up replacing them all on that amp as I am using it a lot and the OT is nearly irreplaceable. My 2100 has a mix of original and replaced caps and I will only replace any when there is an issue.

If I owned the MC50's and was planning to keep them both, I probably wouldn't replace them unless there was an issue, but then I have (too many) other power amp options to use when one is down and I can replace them myself whenever needed. If you are looking to keep one and sell the other, and reliability for the next 10-30 years is important, then it might make sense to have someone go through them both and maybe get one fully serviced and sell the other. The big cans on the outside and the big silver one inside will be the most expensive, but labor will add up depending on what kind of techs you have in your area.

As for testing, a listening test is OK, and in that case hitting them hard and loud will expose failing but not failed main filter caps that might be OK at lower loads. Personally, I would test using a capacitance meter and not just listen(because I can), and that's what a tech should do.

FWIW, I can't see the big external cans, but all the electrolytic caps I can see on both amps do look like they have been replaced, but I can't see date codes to know when. Also, the big orange caps are not original and not supposed to be in that location and there are two resistors missing from those boards (likely relocated with smaller modern resistors) which suggests both amps were serviced by the same tech at some point. So, you may be good to go already. Do you know the history of them? When they were last serviced?

Do they both sound good at apartment volumes? Do they sound the same? Are you going to be gigging them with/without a backup? Do you need the money from selling one? Are there any techs with McIntosh experience near you? These are questions that should guide you on what to do.

The video shows that there is not much hiss or 50 cycle hum turned down and the Klipsch speakers he has have a sensitivity that is relatively high for home audio speakers and more similar to something like a JBL D/K120 so that's a very good sign. Hard to do any critical listening when not in the room, but I heard nothing that would make me think there is an issue with either of them. The fact that they were serviced and caps replaced is a big plus. It will need to be done again, but who knows how long from now? 5 years? 50 years? Longer? That's part of the gamble with vintage gear.

If it was me and my money, I would probably take the chance based on the video and the hope that the seller is honest. That said, I am my own tech and I live a couple hours away from the factory where they were made so I could fix any issues a lot easier and cheaper than you probably can. The good news is parts are available and can be shipped to France a lot cheaper than a full amp, so if something does go bad, the biggest issue will be finding a good tech. The audiophile community would be where I would ask if needed.

One caution though. Given what these things cost in the US, I am assuming this is a rather substantial investment in guitar tone. I think it's important to point out that the difference between a vintage MC and other good quality power amp options is going to be pretty subtle. You definitely don't need a McIntosh to get great Jerry tone, virtually no one but you will ever notice, and many forum members and other Deadheads in the US who have used them have switched to smaller lighter more convenient options, at least for use outside the home. It's a cool/fun to own luxury item, not a rational use of money!

Good luck with whatever you decide!

Chocol8 wrote: ↑Tue Mar 17, 2026 1:57 pm The video shows that there is not much hiss or 50 cycle hum turned down and the Klipsch speakers he has have a sensitivity that is relatively high for home audio speakers and more similar to something like a JBL D/K120 so that's a very good sign. Hard to do any critical listening when not in the room, but I heard nothing that would make me think there is an issue with either of them. The fact that they were serviced and caps replaced is a big plus. It will need to be done again, but who knows how long from now? 5 years? 50 years? Longer? That's part of the gamble with vintage gear.

If it was me and my money, I would probably take the chance based on the video and the hope that the seller is honest. That said, I am my own tech and I live a couple hours away from the factory where they were made so I could fix any issues a lot easier and cheaper than you probably can. The good news is parts are available and can be shipped to France a lot cheaper than a full amp, so if something does go bad, the biggest issue will be finding a good tech. The audiophile community would be where I would ask if needed.

One caution though. Given what these things cost in the US, I am assuming this is a rather substantial investment in guitar tone. I think it's important to point out that the difference between a vintage MC and other good quality power amp options is going to be pretty subtle. You definitely don't need a McIntosh to get great Jerry tone, virtually no one but you will ever notice, and many forum members and other Deadheads in the US who have used them have switched to smaller lighter more convenient options, at least for use outside the home. It's a cool/fun to own luxury item, not a rational use of money!

Good luck with whatever you decide!

Thanks again, man! It really helps a lot
I think I’ll take the chance. I like to trust people, and I’ll kick myself if I don’t buy them after looking for these amps for so many years.
Good to know that the parts are available in case anything goes wrong with them in the future.

Regarding your last point, how subtle are you talking about? If you had to give a percentage of the impact of the power amp, compared to the other variables (preamp, speakers, guitar pickups)—not taking the guitar player into account—what percentage would this be for the McIntosh amps?

I’ve read tons of threads on this forum of musicians saying that they noticed a significant difference between their good power amps (Crest, QSC, Carvin, etc.) and a transistor McIntosh with AT.
Were they all exaggerating? Placebo?

I know that the preamp and speakers are much more important when it comes to the tone of the amp, but aren’t the MCs necessary to achieve that bell-like tone and attack Jerry had (think of 1981 “Althea” live solos, which are not really clean but not overdriven either, while being very bright yet not piercing or unpleasant at all)?

I currently have a QSC PLX1202, which is a very good amp, but first of all it has very loud fans that are impossible to turn off. And last but not least, I feel like it’s missing something—some personality, a je ne sais quoi—but it might just be because I only play it at a reasonable volume.

I also have the complete Jerry Garcia amp/effects gear from the ’60s to the ’90s:
Groove Tubes Trio, SMS Classic preamps, JBL E120 and K120 speakers, a Real Tube Reverb RT-921 (which I got recently), a Lexicon PCM70, and all the pedal effects he used without a single one missing.

The MCs are the last piece of the puzzle, so even if it’s only 10% or even 3% of the sound, I think it’s worth having the full gear

https://www.youtube.com/watch?v=slzGZZv9AW0
https://www.youtube.com/watch?v=SjKossVY1mQ
https://www.youtube.com/watch?v=LsbWbddMA-o

Here are some old videos of me playing on my Tiger and Wolf replicas through my QSC PLX1202 with the GT Trio + a cab with one K120 at bedroom volume, recorded with a MD421. My playing was okay, and I feel that my tone was missing something (and definitely not bright enough except the one with the Wolf), but again that’s probably because I wasn’t cranking the amp, not because of the missing MC, right?

It's really hard to quantify impact.

I would say the biggest impact going to something like the Mc is the transients. The big iron and big capacitors mean a more robust power supply to keep pace with what you throw at it. The more you push the amps, the more noticeable the difference will be, but the Mc behaves more like a robust tube power amp.

This will be a bit technical, but the Mc has a medium to low damping factor, similar to many guitar tube amps with average negative feedback. The impact of this is how the amp reacts to the speaker load. From a hifi sense, higher is better, but from a guitar perspective the Mc behaves more like a tube amp than a modern SS amp including pro amps like your QSC or any of the Class D options.

The next part would be Jerry running his with an impedance mismatch and running it hard. That will add a little character when the amp distorts a bit. You will need to driving your JBL's to pretty loud levels before this comes into play. Basically you will want to be wearing hearing protection unless on a large stage/outdoors. You won't get that effect at apartment volumes without attenuation which I don't recommend, so you will want to get your little bit of grit from a pre-amp or pedal.

Ok so you're basically saying that I will probably won't even notice a slight difference between my QSC and a MC50 when playing at apartment volume, is that correct?

What about hi-fi listening? Would there be a noticeable difference between my QSC and the MC50 in a hi-fi setup with a turntable and CDs at moderate volume?

No, I think you will notice a slight difference, but not a major one.

Hifi listening will be a bigger difference, depending on the rest of the system and music sources.

All that said, one man's slight difference is another man's night and day. From my perspective a major shift where my wife notices would be night and day. My Brown Pro vs my Blackface Super are two amps with similar tubes and power but very different voicings. Anyone who can hear will notice the difference. Two Strats with identical pickups but rosewood vs maple fingerboards is a subtle difference to me. Point it out and ask my wife to listen carefully in an A/B and she can hear it, and tell you which one is a touch brighter. Play a blind recording of just one in a band mix and almost no one is going to know what kind of fretboard it is.

So, I don't think you are going to plug it in, strum a few notes and immediately say, "Oh my! THAT'S the tone I have been looking for!" Your QSC is already significantly better than a cheap low quality Class D pedal amp, so it's simply not going to be a big change. If my wife heard you playing the QSC, went to get a coffee and came back while you were playing through an MC50 she probably wouldn't notice anything had changed unless you pointed it out.

There are not a lot of guys active here anymore but I think a few of them have experience with McIntosh and other amps and can maybe offer their perspectives. My opinion is that from a purely tone perspective, the MC is totally not worth the money, especially for gigging. That said, I own one because I can and I want to. If you have every other piece of the signal chain, and the Jerry guitars, I would guess that owning a McIntosh will be worth it to you as well, but I don't know the cost, your finances or how your brain works vs mine. I would say that if you can afford it, and it's the only way you can spend some serious time trying one out at home with your gear, go for it. Otherwise you will never know. Ultimately, if you decide you don't like them or they are not worth it, you can sell them, hopefully at minimal loss. But that's my thinking, everyone's situation is different.

I see.
To be honest I’m starting to have second thoughts now—mostly because there are two of them, and €2000 (around $2300) is a pretty big investment for what might be a relatively small impact on the overall tone.

That said, they’re getting harder to find, especially here in Europe, and this pair is in really clean condition, so the price might actually be fair.

Still, it’s hard not to hesitate when I read older forum posts from people who managed to pick them up for under $500 just a few years ago.

I canceled my meeting with the seller; I think I need to give it more thought.

LOL, I was going to guess €1000 apiece based on your earlier comments.

tdcrjeff wrote: ↑Wed Mar 18, 2026 2:16 pm LOL, I was going to guess €1000 apiece based on your earlier comments.

Yeah, definitely not a steal at this price, but not so bad either where I live.
A lot of people are trying to sell their MC250 for 2000€ and more...
And the MC50 seem to be much less common than the MC250 and the MC2100 here.