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Classic Mac Sound

67.253.54.149

Posted on February 19, 2017 at 11:10:14
Posts: 573
Location: Maine
Joined: August 16, 2011
Hi,
I think I need some help on this one.
What is that Classic Mac Sound?
I was wondering how the MacIntosh C-22 reissue preamp would compete sound wise with something from Audio by VanAlstine or Nelson Pass or other makes less than 6000 bucks.
I had the latest Absolute Sounds 2017 Editors Choice Awards issue. This is what it said;
The C-22 has that( Classic Mac Sound ) made contemporary with greater transparency and much lower noise and distortion.
So if you want to know what that classic Mac sound is the answer; might be less transparency with more noise and distortion.
Then I wondered could Stevie Wonder walk into a room and tell you it was Macintosh playing because of a certain classic sound?
Do those nice aqua blue lights have anything to do with the sound or the fantastic build quality?
Just something I thought about. I was wondering what is that sound? Hey thanks alot for any replies....have a good one...Mark Korda


 

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RE: Classic Mac Sound, posted on February 19, 2017 at 18:29:10
6bq5
Manufacturer

Posts: 2160
Location: SF Bay
Joined: August 16, 2001
Contributor
  Since:
September 14, 2012
THe Classic McIntosh sound comes from their transformers - in the power amp side- and from a 'More is better' on the Pre-amp side.
McIntosh, Like the early Marantz had absolutely amazing output transformers for their tubed gear - all were Ultra-linear in topology and were potted. they had great frequency response and have a great sound.
they do not have high damping factor - hence the 'soft bass' and often the early units only were tested up to 16,000cps (Cycles per second=Hertz) so did not go the extra 4-10KHz in top end definition...
As McIntosh introduced transistors (SS) into amplifiers - they put 'Autoformers' on the output side. this did a few things - one made the amp stable into any speaker- and carried the 'house sound' into the ss gear.

Do new production units have the same sound - not fully, but close- they have expanded the frequency range of the OPTs but kept the original circuit - though with better components-

Happy Listening

 

RE: Classic Mac Sound, posted on February 19, 2017 at 19:20:20
fantja
Audiophile

Posts: 10033
Location: Alabama
Joined: September 11, 2010
Let me know when you get a demo- Mark.

 

RE: Classic Mac Sound, posted on February 20, 2017 at 06:48:32
Posts: 573
Location: Maine
Joined: August 16, 2011
Hey,
Great answer 6b!
Fanta, I use the poor mans MacIntosh, Dynakit. In 2 really good builds I still get a transformer hum with nothing playing and my ear close by. Do the Mac transformers do that?....thanks you guys...Mark K.

 

RE: Classic Mac Sound, posted on February 20, 2017 at 06:52:01
seas
Manufacturer

Posts: 128
Joined: December 21, 2006
The McIntosh circuit topology was not Ultra-linear. They had a patent on so-called "unity coupled" amplifier circuitry, which was the basis for all their tube designs from the MC 30 on. They made use of a special transformer winding technique along with a cathode winding to provide large amounts of local feedback around the output stage.

 

RE: Classic Mac Sound, posted on February 20, 2017 at 11:40:39
6bq5
Manufacturer

Posts: 2160
Location: SF Bay
Joined: August 16, 2001
Contributor
  Since:
September 14, 2012
Mea Culpa- Unity coupled vs Ultralinear-
My appologies
Happy Listening

 

RE: Classic Mac Sound, posted on February 20, 2017 at 13:20:17
Posts: 573
Location: Maine
Joined: August 16, 2011
Hi Guys,
I saw this video on the making of the Mac 275 power amp. When they got to the transformers they were pouring this tar goopy like liquid into the housing or bells to seal them up.
I know the Dyna transformers didn't do that and would that process make a more silent transformer?
Why I started this thread was not only the Willie Nelson cigarette I smoked but the fact of believing all this time from reading stereo mags that the best preamp is the one that least colors the signal. Barring tubes vs. transistors debates the 6000 dollar C-22 came into view.
So when the reviewer said the pre amp had that classic Mac sound it threw me for a ground loop.
Every time you guys write I get a great audio lesson...keep em coming....thanks Mark K.

 

RE: Classic Mac Sound, posted on February 20, 2017 at 13:42:12
6bq5
Manufacturer

Posts: 2160
Location: SF Bay
Joined: August 16, 2001
Contributor
  Since:
September 14, 2012
Transformers are an interesting element of the audio chain-
The can generate noise
they - in the form of output x-formers- define the frequency response of the amp

however if well made- can make a unit be sublime-

putting that 'tar goopy' stuff in does a few things -
1: if done well, the material can get into the air spaces to keep the transformer quiet (from mechanical noise)
2: protect the windings from the lams - consider it added insulation
3: enable the transformer to be more uniform with respect to heat - and to then transfer the head to the external surfaces-

This is usually called 'potting' or potted transformers
not many people do it any more, as it adds expense...

but some of the best amps made have potted transformers-
Happy Listening

 

RE: Classic Mac Sound, posted on February 21, 2017 at 07:48:52
stellavox
Audiophile

Posts: 284
Joined: June 23, 2004
Our Connecticut Audio Society has been fortunate to visit Mac twice. Once in 2007 and again this past fall. A link to pics a few members took on the '07 trip is attached.

If interested, I'll try to dig up a link (if it exists) for the latest trip pics. As you probably know, a lot has happened there in 10 years but their commitment and drive remain the same.

https://sites.google.com/site/mpbarneytuners/

Charles

 

I do not think much of 'Classic Mac Sound' just old fashioned muck with grain., posted on February 21, 2017 at 11:11:01
3+4=5
Audiophile

Posts: 397
Location: Midwest
Joined: December 24, 2016
The last time I listened to MAC gear was auditioning to buy new preamp and amp in 2010.
I was totally disappointed with the MAC grung with extras sound.

Which is the same a any 70's mainstream Japanese transistor sound but a little darker, murkier.

 

RE: Classic Mac Sound, posted on February 25, 2017 at 19:34:58
goldenthal
Audiophile

Posts: 600
Location: Ontario
Joined: March 28, 2003
Mark:

I guess I own "classic Macs" sort of. My amps are 2 1960s Mc 275s bridged for mono. I drive my nominally 8-ohm speakers as if they were 4-ohm because their impedance drops to 6.3 ohms and they are said to present a reactive load. The Mc 275s have been great amplifiers in my experience: quiet, neutral, long-lived, easy to maintain. Mine have been modestly modified -- extra capacitance, and a bit of feedback around the output transformers. I can't say those changed their sound much -- though I have owned and used other amps over the decades, the 275s have been true "set-and-forget"; their long-term sound causes me to forget to "upgrade" (assuming that's possible).

The "classic" 1960s C22 is another matter. Again, it is quiet and well built. But as sold it had a wider RIAA tolerance than we'd accept today; the phono stage in mine as it is today is far more accurate. Even more importantly, at least to my ears, the original C22 seems to have had its front face designed first, before consideration of internal lay-out, with the internals made to fit between that and the back panel. The result is a woeful lack of stereo separation, generated by capacitive coupling between channels. Through its phono inputs, mine measured as low as 6 dB (!) at some settings of the volume control when I acquired it. (Was that "normal-average" when the C22 was designed?) Fixing that was a lengthy matter of soldering in shielding in many places inside the chassis. I found the sonic improvement from that fix much greater than that from "flattening" the RIAA curve. Don't misunderstand -- the original had the virtues of tubes -- no stridency, no flatness or hardness. But it can be greatly improved.

So, ref. the Absolute Sound quotation, "much lower noise and distortion"? -- I doubt it. But "greater transparency"? -- quite possibly. That's what serious modifications conferred on my original if transparency = a huge opening up. On the other hand, McIntosh seems to have remained fastidious, even obsessive about their external appearances, and who knows whether some of the same sins are still being committed. Measurements would show, but they're increasingly rare. And my current tech says, FWIW, that the old Macs were much better built than the new ones. Of course, that could be merely that he has a fetish for point-to-point wiring.


Jeremy

 

RE: Classic Mac Sound, posted on February 26, 2017 at 08:52:41
Posts: 573
Location: Maine
Joined: August 16, 2011
Hi Jeremy,
That was a great answer! I'll bet the reviewer who wrote what I read should of knocked heads with you for a while. Thanks for taking the time to write all that. A nice slice of vintage/present history strait from the owner...Mark Korda

 

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