My vintage McIntosh MX-110 preamp surprised me today. Follow up post #61!

Thanks for the info! Wasn't sure how early it was. A piece of audio history it would seem.

 

55 years and counting. But it is a McIntosh.

Bob

 

I refer you to my signature.

 

Steve's right. The midrange on this is spooky good. Listening to June Tabor this morning and getting goosebumps. Doesn't happen enough for me anymore. I sure like when it does. Doesn't just happen on any tube gear that I've owned. I used to get a similar reaction listening through a Fisher 400. Wish I still had that, but this 110 is taking away the sting of that loss.

This is the album btw

 

Page 12 in the MX110 owners manual clearly states, "The input impedance of the amplifiers should be 100,000 ohms or greater."

In the C22 manual, "The input impedance of the amplifiers should be 50,000 ohms or greater."

In the highly unlikely event that both manuals were misprinted, at random I also checked the C28 manual which, sure enough, states, "The input impedance of the amplifiers should be 47,000 ohms or greater."

First series McIntosh tube amplifiers made into the 1960s have input impedances listed at 250,000 ohms; 500,000 ohms for the MC30 & MC60.

This further suggests the amplifier input impedance recommendations of the MX110, C22 etc are indeed the values McIntosh intended to represent.

If anyone can answer why it should be otherwise, I'm all ears.

 

Yes that is what McIntosh recommended. But it is also true that Terry did say what he said, and having now used my 110 with a Harman Kardon Citation 22 amp which I believe is about 22k ohms(if anybody can correct I would appreciate...really hard to find a specific figure anywhere online) I would have to agree. I'm assuming that with the recommended impedance the presentation would be fuller, and louder. I'm using very efficient Klipsch Cornwalls, and don't play stuff that loudly anyway. I get good bass, although at lower levels I have been employing the loudness switch. In any event, I am planning on using the 110 with Dynaco MkIII amps(in whatever century the tech can get them back to me), and would very much like to try it with a vintage Mac amp. I'm leaning towards a MC250, as that's about right for my budget and speakers.

Ultimately, I would say that like most anything in this hobby one must try to listen in their own room with their own gear to get a sense as it will be right nor not for them. The numbers are important, but more so as a guide, then as an absolute rule. IMO, of course.

 

Yes but in this case we are not discussing an impedance mismatch of say 10% +/- or so. We are talking a factor of 5:1 or 10:1 (depending on who you ask).

Given that nobody in his right mind would ever expect a phono cartridge to perform properly with such an impedance mismatch, it's difficult to understand how a mismatch of similar multiples between components would not affect performance in some way.

Whether or not it is audible is another discussion entirely, which may vary from one listener to the next.

While I have infinite respect for Terry's judgement, I'd like a bit of clarification before casually dismissing McIntosh's expressed recommendations which are unlikely to have been made without good reason.

Again, were we talking a couple of percent, I wouldn't ask questions. But we are talking a serious disparity here. Either someone is very right or very wrong.

 

Not disagreeing with you, just relaying back my experience. Probably a great question to ask Terry. He's been pretty adamant in his comments and it would seem his opinion should carry some validity.

And again, I think the term "properly" carries with it it's own baggage. If it sounds good to the listener, isn't that the most important variable? There are loads of people that will scream out their lungs that you can't listen to AR 3's properly unless they have at least 100 watts of high current power pushing them. I've used 20-30 watt tube amps with mine and loved the way they sound. To each their own.

 

Please refer to the post again which I had amended. Thanks.

 

I agree.

I don't think Terry was "casually dismissing" McIntosh's recommendation, but rather expressing his opinion based on his experience. I don't recall him ever saying that McIntosh was wrong in their opinion. Again, my amp works just fine with the 110. Would it satisfy everyone? I don't know. But after being an audio listener for almost 50 years, I would say that I know what sounds good to me, and what doesn't.

 

Thank you for sharing your experiences with the MX110 which I do not question are truthfully and sincerely made. In any case I would be grateful if someone could provide some further clarification on the matter.

Glad to hear you're enjoying your MX110.

 

I called Terry like I said in an above post and that's what he told me, that you could pretty much run any amp with the MX110 with no problem. He said you could even go down to 1000 ohms. Now my Emotiva is listed at 26000 ohms, so I mostly just wanted to make sure it was okay. I just got my MX110z in the mail today and am pretty stoked, I will just have to try it out and see how it sounds with the Emo. The tuner section, just playing with the flywheel dial seems pretty solid, and I believe the mx is in pretty good shape. I will probably have to see about getting it serviced here locally in Colorado Springs, Terry is on vacation for three months and then he will have a backlog of at least 90 days after that.

 

I'm sure it will be fine with your amp, assuming it's in good working condition. At worst you may need to turn up your volume a little more and adjust the tone and loudness to meet your preferences.

I've decided to get a Mac MC250 to try out with mine. I think it will be a nice match for my Cornwall II speakers anyway and with a impedance of 200k what Mac recommended. We'll see what difference, if any it makes in my system to my ears.

 

The MC250 is an ideal companion for the MX110 this side of a '60s-era McIntosh tube amplifier. In fact, I've found little to no audible difference between the MC2505 (metered version of MC250) and various tube McIntosh amplifiers after considerable listening comparisons.

I'm going to have to speak to Terry directly about this impedance question: 1,000 ohm is 100 times the maximum resistance McIntosh specifies for amplifiers to be used with the MX110. Although McIntosh published specifications are generally conservative, this is a massive disparity.

 

I'm really looking forward to the 250. Ordered it this morning from Audio Classics, my first order with them. I'll then be able to be in a better position to discuss the impedance matching and sonic differences.

 

Well, I fired it up and I guess it's not in as good a shape as I thought. Has a hum in all switch settings. I have it in the shop for repairs. Probably the power supply, plus it needs a few other things fixed on it.

 

Eventually I would like to get a Mac amp to match it, I was reading about the 2200 and 2505.

 

Sorry to hear that. I'm sure mine could use a refresher as well, but I'm enjoying as is so for now that's on hold.

I'll be interested to see what sonic improvements I notice. I have been noticing that with my current set up of a Harman Kardon Citation 22 amp that the sound can be a bit on the edgy side, and I'm wondering if that is a symptom of the 110 having difficulty driving a lower impedance amp. So we'll see if things round out a bit when the new amp arrives on Tuesday.

 

250 come in yet sberger?

 

Due any time now(when UPS says delivery "by the end of the day" they mean it!).

 

Well it finally arrived, and it's terrific! Right off the bat the most noticeable difference between it and the Harman Kardon Citation 22 that I was using is the weight of the music through the Cornwalls. Acoustic music too. The first few things I played were tonally significantly more muscular then on the HK, and given that it's 200 watts, while the 250 is 50-70, I'm going to chalk that up to increased impedance of the 250. And of course, the 250 was brought up to spec by Audio Classics , and the 22, to the best of my knowledge, is stock.

Didn't know until a bit of research that the 250 gets plugged into the the 110. Nice to have one more spare outlet.

It will be interesting how my Dynaco MKIII's match up to the 250. That is if they ever make it back from restoration purgatory.

 

didn't realize you had cornwalls too. you've got my dream system, sir. still sounding great?

 

First rate vintage setup. Well done.

Now all you need is an MPI4.