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to re-cap or not to re-cap Mcintosh C20

primosounds said:
Telefunken ecc83 have a reputation that is deserved but procuring replacements can be give people sticker shock. A long time ago I started collecting all brands of vintage 12ax7 when i was using them in my equipment and tried different brands just to see what difference that would make in sound quality. One thing i learned was that a strong tube was important to performance. So, new tubes always had the advantage because they had good emission. Now, how long that ability lasts is maybe a different story vs vintage tubes.
When i rebuilt my buddy's Mac preamp i auditioned it in my main system for a bit just to know what it sounded like so after rebuilding i had a frame of reference to speak to after installing the new caps. And i thought the new caps improved the sound in areas of dynamics and soundstage. The new parts did not have enough time to break in so overall i felt the new parts were an improvement with around 10+ hours of use. As always YMMV.
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yeah, the NOS Prices are a bit wacky. may stick with some new Russians, just trying to narrow options down without breaking bank. let me restate that, I will break bank, if I was certain to be blown away by a considerably noticeable difference with NOS.
 
cocovinyl176 said:
yeah, the NOS Prices are a bit wacky. may stick with some new Russians, just trying to narrow options down without breaking bank. let me restate that, I will break bank, if I was certain to be blown away by a considerably noticeable difference with NOS.
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I don't think it is wacky, it is just supply and demand. There are many reasons why the demand is high and in a perfect world it would be because the product is superior in some way. Unfortunately since there is a collector value that issue skews the price upwards.
 
Russians are still making 12ax7's, the Germans quit decades ago.

I don't know this preamp at all, but some things have spots where tubes matter more than others. If this has cathode followers, generally that tube just isn't all that critical. You can run less amazing tubes in those locations and save the fancy stuff for where it matters.
 
gadget73 said:
Russians are still making 12ax7's, the Germans quit decades ago.

I don't know this preamp at all, but some things have spots where tubes matter more than others. If this has cathode followers, generally that tube just isn't all that critical. You can run less amazing tubes in those locations and save the fancy stuff for where it matters.
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Gadget, I just bought some 10mm RCA BlackPlate 12ax7's NIB Never used, from 1951, scared to use em! You don't want to know what I paid either......:).
 
I own 3 of the C-20 preamps. All 3 were basket cases when I got them. I replaced every single internal component except switches and pots. They all sound quite good now. These preamps are overly complicated with a ton of capacitors. The C-11 which overlaps in production with the C-20 is more modern and somewhat simplified and I think it sounds better. Although they both sound good.
 
Hello guys, I'm sorry to say that you're totally missing the point in my estimation. These old components do have their merit and worth, even if they seem to have been outdated nowadays. The original stock C20 is able to produce a kind of sound which is totally natural in acoustic terms [speaking from an audiophile standpoint], something which is much praised by collectors worldwide. It feels as if the sound was not going through electronics, i.e., the sound it outputs is free of electronic-like artifacts and just sounds like a pure acoustic event through speakers. Should you exchange those components for modern-day, audiophile-grade caps like Mundorfs or 'parts connexion-grade' caps, that magic is lost forever, being replaced by a kind of 'high-definition' sound which is in fact boring and fatiguing in the long run, and does not translate into musicality but technicality really. Of course it all depends on your listening bias and goals, but if you're looking for a nice 'musical instrument' quality and not an 'electron-beam microscope' to reproduce your music, the way to go is to keep it stock as it came (a piece of gear which is something rare to find these days). Just replace that which needs replacement, but nothing else. Talking about tubes, the best to use are NOS Telefunken's, GE's, RCA's or Sylvania's. Advice from a seasoned audiophile who's seen it all before, though YMMV!
 
Wram said:
Hello guys, I'm sorry to say that you're totally missing the point in my estimation. These old components do have their merit and worth, even if they seem to have been outdated nowadays. The original stock C20 is able to produce a kind of sound which is totally natural in acoustic terms [speaking from an audiophile standpoint], something which is much praised by collectors worldwide. It feels as if the sound was not going through electronics, i.e., the sound it outputs is free of electronic-like artifacts and just sounds like a pure acoustic event through speakers. Should you exchange those components for modern-day, audiophile-grade caps like Mundorfs or 'parts connexion-grade' caps, that magic is lost forever, being replaced by a kind of 'high-definition' sound which is in fact boring and fatiguing in the long run, and does not translate into musicality but technicality really. Of course it all depends on your listening bias and goals, but if you're looking for a nice 'musical instrument' quality and not an 'electron-beam microscope' to reproduce your music, the way to go is to keep it stock as it came (a piece of gear which is something rare to find these days). Just replace that which needs replacement, but nothing else. Talking about tubes, the best to use are NOS Telefunken's, GE's, RCA's or Sylvania's. Advice from a seasoned audiophile who's seen it all before, though YMMV!
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No. Save your money buy music instead and save your Mcintosh
 
Mine was re-capped by Dave O'Brien at one of the last McIntosh Clinics in St. Louis. He didn't seem to like the results when he first ran the test so he asked if he could keep it overnight. I got it back the next day and Dave was pleased to be able to get it back to original specs. The only thing he had no solution for was the "cross-talk" between input sources that he attributed to the circuit board material. Some remark about military-grade sticks in my memory. I haven't touched a thing on it since then. Whatever tubes it has were put in by Dave from Macs stock. The first step in their testing at the clinics was always to throw away all tubes and start with fresh ones. So much for the necessity for burn-in.
 
BMWCCA said:
The only thing he had no solution for was the "cross-talk" between input sources that he attributed to the circuit board material.
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old phenolic that got electrically leaky perhaps? I've had that happen on source selectors before.
 
Had my mx110z recapped/restored and it sounds beautiful, not fatiguing at all.
 
Everyone talks about the sound of original components, but unless you were a Mc engineer in the late 50's or early 60's and listened to these models extensively when all the parts in them were new, how is anyone supposed to know now what they originally sounded like? Can you really claim the sound from a perfectly running, completely in spec 1961 vintage mc pre amp is exactly the same now as it was 60 years ago? I for one would claim that no matter how well preserved the parts might be, they are still all 60 years old, and I don't care what an electronic component is made of, 60 years is going to take its toll one way or another. Perhaps vinyl might be more or less unchanged in 60 years if it's stored properly, but electronic parts? Especially if they've been subjected to the stresses generated by electricity and heat? And personally I've stopped using vintage Sprague Vit Q caps since one took a dump in my 01A pre amp and leaked oil all over the bottom plate. Remember, rust never sleeps, and the law of entropy is inescapable....
 
Interesting debate I think it's just a matter of perspective...

There's so many things that affect the flavor of classic audio...

I don't think it matters to my ears as much as others...

It depends on what you want... Not on what we think...

Me I'd restore it with all new components so I was certain that everything was operating good for many years to come...

As to type of components the best I can afford as close to original parts as I can afford to get new...
 
analog addict said:
Everyone talks about the sound of original components, but unless you were a Mc engineer in the late 50's or early 60's and listened to these models extensively when all the parts in them were new, how is anyone supposed to know now what they originally sounded like? Can you really claim the sound from a perfectly running, completely in spec 1961 vintage mc pre amp is exactly the same now as it was 60 years ago? I for one would claim that no matter how well preserved the parts might be, they are still all 60 years old, and I don't care what an electronic component is made of, 60 years is going to take its toll one way or another. Perhaps vinyl might be more or less unchanged in 60 years if it's stored properly, but electronic parts? Especially if they've been subjected to the stresses generated by electricity and heat? And personally I've stopped using vintage Sprague Vit Q caps since one took a dump in my 01A pre amp and leaked oil all over the bottom plate. Remember, rust never sleeps, and the law of entropy is inescapable....
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cocovinyl176 said:
Hi All,

I have a c20 I recently sent to a tech. Prior to bringing it in, I was pretty confident that there were for sure leaks and a recapping was inevitable. After benching it, good News, all of the original bumble bees are in great shape and in tact. As it turns out, I need some new tubes and a good cleaning. My dilemma is, even with the old caps in good shape, do I still recap? I have heard about the mystic of these bumble bees on one hand, but have also heard that replacing them with modern caps will provide more depth. I understand a collector may want to have this pre all original. is there that much of a significant change in dynamics should I chose to replace all of them? Also, on another note, can anyone recommend (non-NOS) manufactured tubes for this pre? I plan to uniform them with one brand, even though I have a few tele's that are still in good shape.

thanks as always-
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I have to chime in on this one. This isnt about your valves (tubes). Youre on track with that issue. Find a dedicated MAC thread and forum and see what others have had good luck with. The up-to-date thinking is dont go with NOS tubes anymore...

There hasnt been a vintage piece of gear Ive had my hands on or have seen or have heard talked about in 40 years that HASNT needed a full recap to begin with, regardless of the original or current value. It isnt just about "modern caps (lytics)". 99% of vintage gear had most new gear has/had general grade lytics and other caps to begin with, with only a 10 year shelf life. Thats not use life. Just like others have stated, they turn into resistors and are all dried up. The infamous black or blue lytic syndrome.

You will be soo surprised after burn in if you completely recap with tier 1 brand lytics, and even replace some with tier 1 polys and films in the audio paths. It does not degrade the value. That misinformation still raises its ugly head sometimes. The tire analogy in this tread is exactly true!

If it was me Id recap all with the freshest Nichicon and Elna lytics I could obtain, and see in a dedicated MAC forum or thread(s) what would lytics could be replaced with polys in the audio paths. While youre in there you can also look for old crumbly carbon resistors that need replacing with new metal film resistors.

If a guy would do all that in the recap, Im envious of you hearing it after the 10~30 hour burn in :).
 
You could strip it back to just the tin, make new boards, and populate them with all 100% new components (from Mouser not snake oil direct) you'll have one of the nicest tube preamps on earth.
No comparison with any unrestored vintage piece. Nobody goes to that level of effort but those who do get a very special prize.
You get to have one of the only truly Perfect functional c20s on earth.
I wouldn't stop at a recap, I'd source new tube sockets wiring, boards, and screws, ultrasonic clean each switch. Pots are going to be a challenge to source but replacing all of them is probably a good plan...
Of course if you plan on selling it you'll need to find a buyer who's buying for performance not for originality and collectability.
 
This is the same pervasive discussion among vintage guitar amp owners; do I re-cap and "ruin" the value, is the "vintage" sound the result of CC resistors and various coupling and filter caps drifting and I like that sound, etc. My opinion is that the amp didn't leave the factory with everything out of spec, and I don't want operate it that way - I want it to function properly.

With audio gear, I've worked on about 25 pieces of vintage gear and have found the following to be true. Power amp main filter caps are often still in spec after 25-30 years, but some have failed miserably. Some sound fine but test poorly in operation, and some sound and test great. With preamps, a much higher percentage of old filter caps have failed, either through high internal resistance and/or severe drift in capacitance, leakage, etc. Coupling caps are another story - the smaller electrolytic caps definitely have several failure modes that make them useless and even hazardous to the rest of the circuit. I also agree with trainbuftony that once you open up the chassis, it makes sense to clean, lubricate and inspect everything. I would not replace everything that is still in good order; maintenance is what I think is reasonable.
 
Oh yeah, forgot to mention, one of the MX-110s that passed through my hands over the years had the PT fail as well. Luckily I was able to get it rewound for a reasonable cost.

Nothing lasts forever...
 
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