McIntosh Preamplifier help

[Plimpington2]

I posted a bit about a C22 in an earlier thread, but I want to expand this somewhat to other items in this one.

I have saved my coins and am just about to commit to a vintage McIntosh pre-amp. The three I have in mind at the top of the list are the following:

C22
C20
MX110( )
C11

Prices for very nice condition units seem to run $4-5k for the C22, $3-4k for the C20 and substantially less for the MX110 (of whatever variety, I think, but am unsure) - as low as $1800.

I am just about 100% vinyl, so I value a good phono section. Line level for me consists of just a cheap blue-tooth module I can access with my phone.

To me, to be honest, a C20 in perfect condition (with that gold on the right really shining) is the most "attractive" of the 3. Although I REALLY like the way the C11 looks as well. I like the C22 and the MX110 about equally in terms of looks.

A C22 or C20 will bleed me just about dry, and necessitate I run it with one of my other power amps (I have some nice ones, several EL-84 or 7189 based units, an EL-37 based unit, etc. However, the MX110 would leave almost enough money to pick up a pair of 75's.

I am torn. Is the Mx110 a meaningful step down in sound quality over the C's? The prices make it very attractive as a step into the McIntosh ethos.

 

[TSmith8605]

These preamps are 50 to 60 years old so they will all need full electrical restoration to sound and work correctly. If not so restored, the sound quality may be poor or below spec so restoration is required before comparing the sounds of the units and of course before using them.

It would be nicest to buy one that has already been recently restored. If the seller says the unit is "serviced" you should ask exactly what was done. "Serviced" could mean anything from they dusted off the top of the cabinet to a full restoration. So ask for receipts with proof of what was done and when. You could share that list on this forum for advice. Restoration of an MX 110 should include restoration and alignment of the tuner section as well as the pre amp section and so may cost a bit more to restore.

If you buy an unrestored unit, plan and budget for restoration.

Cosmetic restoration is very difficult, so rather previously electrically restored or not, find one that looks great.

Once the unit is restored, it will still require that controls and connectors be cleaned every year or two - applies to all three of your choices.

The MX 110 requires an power amplifier with input impedance of 100,000 ohms or higher and will have trouble feeding an amplifier with lower input impedance than that. So check the input impedance specs on your power amps. New amps tend to have lower input impedance. The C 22 has a different (cathode follower) output design that can drive a lower 50,000 ohm impedance (or higher) amp so the C 22 will be a bit more versatile. I'm not sure about the C 20, but I think it's the same as the C 22.

For example, you mentioned getting some MC 75 amps. The input impedance of the original '60s MC 75 is 250,000 ohms and will work fine with all three preamps. But the input impedance of the 2009 and 2015 versions of the MC 75 is only 20,000 ohms and those amps will not work well with any of the three preamps on your list.

The C 22 has a lot more features than the MX 110, features you probably will not need.

I cannot comment on sound quality comparison between the 3 since I've not heard restored versions of all three in my home system but I believe, if working properly, they all will be great. Some say the MX 110 has a very "magical" sound and it is well regarded.

A nicely restored MX 110 with a nicely restored original pair of MC 75s would be great.

 

[c_dk]

Have you considered a used later model modern Mac tube preamp?

Quieter phono stage, no restoration hassles for another 15 years, will hold value as the previous owner ate the newness loss.

The only part of the MX110 that was not a compromise was the tuner.

 

[Plimpington2]

These preamps are 50 to 60 years old so they will all need full electrical restoration to sound and work correctly. If not so restored, the sound quality may be poor or below spec so restoration is required before comparing the sounds of the units and of course before using them.

It would be nicest to buy one that has already been recently restored. If the seller says the unit is "serviced" you should ask exactly what was done. "Serviced" could mean anything from they dusted off the top of the cabinet to a full restoration. So ask for receipts with proof of what was done and when. You could share that list on this forum for advice. Restoration of an MX 110 should include restoration and alignment of the tuner section as well as the pre amp section and so may cost a bit more to restore.

If you buy an unrestored unit, plan and budget for restoration.

Cosmetic restoration is very difficult, so rather previously electrically restored or not, find one that looks great.

Once the unit is restored, it will still require that controls and connectors be cleaned every year or two - applies to all three of your choices.

The MX 110 requires an power amplifier with input impedance of 100,000 ohms or higher and will have trouble feeding an amplifier with lower input impedance than that. So check the input impedance specs on your power amps. New amps tend to have lower input impedance. The C 22 has a different (cathode follower) output design that can drive a lower 50,000 ohm impedance (or higher) amp so the C 22 will be a bit more versatile. I'm not sure about the C 20, but I think it's the same as the C 22.

For example, you mentioned getting some MC 75 amps. The input impedance of the original '60s MC 75 is 250,000 ohms and will work fine with all three preamps. But the input impedance of the 2009 and 2015 versions of the MC 75 is only 20,000 ohms and those amps will not work well with any of the three preamps on your list.

The C 22 has a lot more features than the MX 110, features you probably will not need.

I cannot comment on sound quality comparison between the 3 since I've not heard restored versions of all three in my home system but I believe, if working properly, they all will be great. Some say the MX 110 has a very "magical" sound and it is well regarded.

A nicely restored MX 110 with a nicely restored original pair of MC 75s would be great.

Thank you, this was helpful

I have been restoring vintage tube gear for the last couple of months (getting better every day, and about to start in on a MAC 1500, which will be my most challenging project yet due to the solid state pre-amp stage). I had HOPED that I would be able to manage any rehabbing of the pre-amp that would be required for optimal performance (excepting any tuner - If I opted for the MX110, I would send that off to professional for the tuner alignment - that being said, I don't really need a tuner. I am drawn to the MX110 because it saves me enough money that I have enough for a pair of vintage MC-75's. The other pre-amps will leave me with my current amplifiers until more money can be set aside.

That being said, I would likely seek out an unrestored unit (though I insist on very nice cosmetics at these figures) to save a bit of money on the front end.

Which raises the question of impedance matching. The MX110 seems much less flexible, as you say. Which is a shame as my current amps will not permit this stop-gap measure until additional funds can be justified.

I sure do like the looks of the C11 with the red rocker switch in the middle. Thats a hell of a nice looking item . . . particularly in a walnut box. hmm . . .

 

[Plimpington2]

Have you considered a used later model modern Mac tube preamp?

Quieter phono stage, no restoration hassles for another 15 years, will hold value as the previous owner ate the newness loss.

The only part of the MX110 that was not a compromise was the tuner.

No, I hadn't. To be honest, I have been in high end audio for a bit, and owned some nice stuff. I know what's capable at the intermediate to high end of modern stuff . . .which doesn't always bring me happiness. Yes, it's GREAT sounding . . . but . . . BUT . . . I've expanded the reach of my hobby to vintage and to rehabbing vintage, which has rekindled my interest in the whole hi-fi "project", if you will. I LIKE the idea of the vintage MAC equipment and the idea of getting to sound the business as part of my own efforts. I've done a couple of vintage pieces with variable success - and I LOVE listening to the stuff. This Mac stuff will be the coup de grace.

I'm looking for a true vintage pre-amp with a pair of mono-blocks with that cool "gothic" Macintosh logo . . .I have a line on the amps. But, I'm up in the air on the pre-amp.

 

[62caddy]

As far as amplifier compatibility with the MX110 is concerned, I wouldn't worry overly. Just avoid models that were introduced after 1976. (Note I used the word "introduced" because there were some models that remained in production as late as 1980 but were introduced earlier that are still compatible with the MX110 impedance requirements.) Roger Russell's McIntosh site provides a quick rundown of production start/stop dates of individual models helping to make that determination.

One well-seasoned Mc veteran who is sadly no longer with us (on this forum, not of this world), used to say the MX110 will get you 90% of the performance of the C22.

 

[twiiii]

Its either a C-22 or a MX 110 Z. A C-11 is a basic C-22 without the new Face or Panlocs. The Power supply is older, also. MX 110 is not a C-22 but has a particular sound all its own. Save your money and get a C-22 MK II. The third version is still around but people haven't turned loose of them to get a C-70. I much prefer the flexibility of the latest C-22. Having a MC input is nice. Some times you can find a C-2200 for a good price.

 

[Plimpington2]

Its either a C-22 or a MX 110 Z. A C-11 is a basic C-22 without the new Face or Panlocs. The Power supply is older, also. MX 110 is not a C-22 but has a particular sound all its own. Save your money and get a C-22 MK II. The third version is still around but people haven't turned loose of them to get a C-70. I much prefer the flexibility of the latest C-22. Having a MC input is nice. Some times you can find a C-2200 for a good price.

Isn’t the C22 MK2 the new “reissue” version, or do I have that wrong?

I don’t have much interest in the C2200. That’s modern amp. I like the idea of vintage.

I’m leaning towards MZ110Z. I think I’m better off spending less there and having enough left to afford the MC75’s rather than use my other amps. . . I like the way the Mac tuners look too when lit up. It’s a hell of a nice look.

 

[damacman]

Isn’t the C22 MK2 the new “reissue” version, or do I have that wrong?

I don’t have much interest in the C2200. That’s modern amp. I like the idea of vintage.

I’m leaning towards MZ110Z. I think I’m better off spending less there and having enough left to afford the MC75’s rather than use my other amps. . . I like the way the Mac tuners look too when lit up. It’s a hell of a nice look.

The MX110z is a popular choice for certain. It’s the only Mc tube unit to feature both a Compactron and a Nuvistor in the tube complement - that also makes it unique. If you can live with it’s limited inputs, then go for it.

 

[62caddy]

I think you'll be happy with an MX110 but keep in mind the chances are high it'll need to be fully refurbished to perform its level best.

 

[c_dk]

I have found that the tuner circuits of the MX110, can "leak" into the other inputs, the only solution was to make sure the tuner was not on station but in between stations.

This was a compromise Mac engineers had to make to insure the tuner was instantly available when selected. While controlling RF emmision is specifically mentioned in the owners manual I have found this not up to today's expectations.

Also remember the phono sections were designed with expectations of the best moving magnet cartridges of their day. To my memory the V15 series of cartridges and their expected loading was the benchmark for most all the Mac engineers I knew.

While exploring my turntable setup issues (and learning experience) with a MacVP in 1979 in trying to use a moving coil Ortofon in a SME arm, I remember it was as much a learning experience for him as we ended up sorting thru a AKG P8ES.

I guess what I am suggesting is that your cartridge choices and expected level of performance could be greatly limited with all these vintage preamps.

 

[62caddy]

I have found that the tuner circuits of the MX110, can "leak" into the other inputs, the only solution was to make sure the tuner was not on station but in between stations.

This was a compromise Mac engineers had to make to insure the tuner was instantly available when selected. While controlling RF emmision is specifically mentioned in the owners manual I have found this not up to today's expectations.

That's extraordinary as my MX110 exhibits no crosstalk whatsoever, regardless of input selected. In fact, it is the only McIntosh I've ever owned that has none through the tape monitor input- with the tuner active, regardless of how loud the broadcast material. In this regard, the C32 or MX113 cannot compare.

I've used it with the Shure V15 III but the phono stage seems to get along equally well with an AT 440 MLa cartridge that I'm presently using.

 

[Plimpington2]

I have found that the tuner circuits of the MX110, can "leak" into the other inputs, the only solution was to make sure the tuner was not on station but in between stations.

This was a compromise Mac engineers had to make to insure the tuner was instantly available when selected. While controlling RF emmision is specifically mentioned in the owners manual I have found this not up to today's expectations.

Also remember the phono sections were designed with expectations of the best moving magnet cartridges of their day. To my memory the V15 series of cartridges and their expected loading was the benchmark for most all the Mac engineers I knew.

While exploring my turntable setup issues (and learning experience) with a MacVP in 1979 in trying to use a moving coil Ortofon in a SME arm, I remember it was as much a learning experience for him as we ended up sorting thru a AKG P8ES.

I guess what I am suggesting is that your cartridge choices and expected level of performance could be greatly limited with all these vintage preamps.

I can’t comment on the bleed through issue, but I have several vintage tube amps with phono stages that perform great with both my MM cartridges (Ortofon) as well MC (Ortofon and Linn) when a SUT is used.

I can’t say if these vintage units perform to the same level as newer offerings. But I can say that in comparison with modern TUBE offerings (at least of the point to point wired varieties), I’m not convinced we’ve moved the bar much over the last 60 years. A “modern” amp seemingly based on variations of these circuits that have been around forever sound really good. I imagine that if care is taken, these older units can sound just as good.

Honestly, does the C22 reissue sound all that much better than a vintage C22 that’s been rehabbed appropriately?? Maybe . . . I don’t know.

 

[62caddy]

Any audible performance differences between vintage & modern tube equipment will depend on the quality of the rest of the system (mainly the speakers), room acoustics and not least, the listener's hearing abilities.

This assumes both are operating to spec & used with a compatible amplifier.

 

[damacman]

And then there’s the maintenance aspect ... MX110 is full of non-sealed switches and potentiometers. All of which require periodic cleaning. In addition, the tube sockets will be a constant challenge given their age.

Whereas a modern C22 has none of these challenges. I used to enjoy working on my system as much as listening to it - so the Mc tube gear I owned was welcomed. Today, I simply don’t have the time or desire.

In which camp are you?

 

[62caddy]

It's not much different than a classic car: Higher maintenance but usually within the grasp of most talented amateurs to work on. Tuners require special skills however.

As with older cars, certain parts may be more difficult to come by but oftentimes older parts can be refurbished where there's a will.

 

[Plimpington2]

And then there’s the maintenance aspect ... MX110 is full of non-sealed switches and potentiometers. All of which require periodic cleaning. In addition, the tube sockets will be a constant challenge given their age.

Whereas a modern C22 has none of these challenges. I used to enjoy working on my system as much as listening to it - so the Mc tube gear I owned was welcomed. Today, I simply don’t have the time or desire.

In which camp are you?

The maintenance and rehabbing aspect of this hobby is what has rekindled my interest. So . . . I’m ok with what needs doing.

Besides, I suspect if the rehab is done well, there will not been significant work required for years and years thereafter. These are 60 years old. If i can get 20 years out of a rehab, that’s more than plenty.

 

[Gearjunky]

I bought a B1 mx110z from Audio Classics about 4 years ago and have not had a single issue with it. Sure they are not as reliable as the newer units and I knew this going in, but I love the look, sound and nostalgic vibe she gives off.
If it’s been properly restored, then it should be problem free for many years to come.

 

[Plimpington2]

I bought a B1 mx110z from Audio Classics about 4 years ago and have not had a single issue with it. Sure they are not as reliable as the newer units and I knew this going in, but I love the look, sound and nostalgic vibe she gives off.
If it’s been properly restored, then it should be problem free for many years to come.

View attachment 1541442 View attachment 1541443 View attachment 1541444

That’s a B1?! It looks amazing. You have pic of it lit up, by chance?

 

[Gearjunky]

Not on hand but to be honest, it’s pretty dim so I have some LED lamps I’m about to swap into it. I already did a c27 LED swap and it looks great and very close to the original lamps. More to come.
This may be the motivation I need to pull the face off and change the lamps LED’s.