Rebuild a McCormack DNA - 1 with "Gravity Base", or move to Purifi?

[Rockdog]

I have a McCormack DNA-1 that's just hit 30 years old. It was rebuilt once in 1999. Still functions perfectly and still retains its sort of punchy warm sound. Subjective opinion obviously, but it always had a really nice musical personality to my ears. However, it's getting quite long in the tooth and I'm concerned about continued reliability.

I spoke with the still-existing business, SMC Audio, that does high-end rebuilds on these the other day and would like to throw it out for opinions. First, I think Steve McCormack has a solid reputation as a quality builder and I even notice non-functioning amps of this model on sale for $800+ with the intention that they will be rebuilt. Rebuilds start at about $2k, with options up to $5k or more.

The basics are a replacement of the main PCB, rewiring, output modules, transformer, pretty much a complete rebuild to a brand new amp. They push the "Gravity Base" option hard, which is what appears to be a heavy brass base or plinth added to the existing chassis. The specifics are obscure but the benefits are touted as "better everything" that you have to hear to believe..

This appears to be within the popular concept of a heavy physical base helping to alleviate vibration and micro-vibration within electronics of all types. Steve McCormack developed the Tip-Toes products many years ago, which consisted of heavy inverted cones to also minimize vibrations in all manner of components. SMC also markets a "Panzerholtz UFO Base" which is made from an apparently very dense wood with outstanding damping qualities. These are said to benefit all audiophile components including speakers and have a set of adjustable pins to accommodate various applications. The base also rotates for best "tuning" .

So, two questions:

1. Considering a basic rebuild of this amp, Gravity Base or not, would I be better off trying a Purifi (which I'm quite intrigued by anyway), or considering the quality and longevity of the original product, would it be worth at least twice the price to rebuild this classic AB amp? (the rebuild is gorgeous as the picture shows)

2. We audiophiles see anti-vibration type products and concepts across the board. It makes sense in things like turntables, or having speakers solidly anchored to the floor, but are micro-vibrations really a concern in solid-state electronics, and have these concepts proven to either measure better or sound better in valid blind comparisons? I have a tube pre-amp and microphonics are always a concern, but even with that, would a sound absorbtive base really alleviate microphonics in a tube stuck into a ceramic socket that would vibrate internally on it's own anyway?

FYI, my system now consists of Revel 228be's, two JL 112 subs, a JL CR-1 outboard crossover, the DNA-1, a Primaluna Dialogue Premium Preamp, a Topping d70s mqa, an Oppo 105, and Bluesound Node 2i. Sensible Blue Jeans Cables throughout, and a solid rack with sand filled legs. I may eventually move to DSP but just learning to measure with REW, my room response already seems remarkably flat.

Thanks!

 

[MRC01]

I have a McCormack DNA-1 that's just hit 30 years old. It was rebuilt once in 1999. Still functions perfectly and still retains its sort of punchy warm sound. Subjective opinion obviously, but it always had a really nice musical personality to my ears. However, it's getting quite long in the tooth and I'm concerned about continued reliability.
...

I have a 29-year old amplifier (Adcom 5800) of similar size, weight, power and design (traditional high bias AB). I check it out periodically (DC offset, bias) and I send it to a local shop every 5 years or so to run it up to full power to check output, distortion, noise. It's still in spec. I believe if it ain't broke don't fix it, service based on condition. I'll keep using it until it fails. Also, I am skeptical of the effect or benefit and thus the need for damping tiny micro-vibrations in electronics. It weighs 50+ lbs., right? So you've got to have it in a solid secure place anyway. Just my opinion, you'll get others here.

Put differently: you paid big bucks for a well designed and built piece of solid state gear. That comes with the benefit of low maintenance and longevity, which you should enjoy!

 

[JeffS7444]

Half a lifetime ago, I worked at an audio dealer which sold a ton of Mod Squad "Tiptoes", but had we known how to perform proper controlled listening tests, I think we'd have had a much tougher time of it!

The best way to deal with microphonic electronics is of course, not to buy them in the first place: Miniaturized SMD circuitry, minimal point to point wiring and painstaking PCB design is where today's state of the art is at. No way I'd sink almost the cost of a Benchmark amplifier into rebuilding that McCormack.

 

[Martini]

I had a DNA-0.5 that was upgraded to "gold" level at the time; it was a solid, wonderful sounding amp. Since it was getting some age on it, I was considering having SMc update/refresh the amp again. However, I wasn't too crazy about some of the things being promoted, like high $$ fuses and the Gravity Base, which they would not describe or explain how it works, being push as "substantial" and "people are amazed" improvements. It sounded then (and still does) like audio-foolery. With what I perceived as BS and the cost of the SMc update, I decided to upgrade to a Benchmark system, which has both manufacture & external testing data to prove its credo. I would recommend not putting your money into another rebuild. Start anew.

 

[MRC01]

... No way I'd sink almost the cost of a Benchmark amplifier into rebuilding that McCormack.

... I would recommend not putting your money into another rebuild. Start anew.

That could be good advice if he does replace the amp. But is replacing the amp a given?

Reading the OP, I get the impression that the amp works, the owner likes it, and he's only concerned about ongoing reliability. If so, Is there any downside to simply keep using it? It might go another 10 years, it might fail tomorrow. But either way, he can cross that bridge when he gets there.

 

[Matias]

VTV has a 30 day trial. Just buy one and see if you like it. If not, return and maintain your current amp.

https://vtvamplifier.com/product/vtv-amplifier-purifi-eigentakt-stereo-amplifier-based-on-eval-1/

 

[Martini]

That could be good advice if he does replace the amp. But is replacing the amp a given?

Reading the OP, I get the impression that the amp works, the owner likes it, and he's only concerned about ongoing reliability. If so, Is there any downside to simply keep using it? It might go another 10 years, it might fail tomorrow. But either way, he can cross that bridge when he gets there.

True.
I was in the same quandary with the options being Keeping it vs. Selling it, while I could still get something for it. I decided on the latter.

 

[Blumlein 88]

Purifi is all you need to know. IMO.

Say I who used to rock a McCormick (Mod Squad) CD player and other gear.

 

[Rockdog]

The best way to deal with microphonic electronics is of course, not to buy them in the first place:

Ha! True, and I'm reconsidering the tube pre, but I can tell you it doesn't exactly sound terrible.. I switch between straight DAC to amp and the Primaluna tube pre, and while I know it isn't SOTA straight line from the signal... it truly is a lovely little second harmonic generator!

Put differently: you paid big bucks for a well designed and built piece of solid state gear. That comes with the benefit of low maintenance and longevity, which you should enjoy!

Certainly a good point, after 30 years I'd say it delivered in spades.

I had a DNA-0.5 that was upgraded to "gold" level at the time; it was a solid, wonderful sounding amp. Since it was getting some age on it, I was considering having SMc update/refresh the amp again. However, I wasn't too crazy about some of the things being promoted, like high $$ fuses and the Gravity Base, which they would not describe or explain how it works, being push as "substantial" and "people are amazed" improvements. It sounded then (and still does) like audio-foolery. With what I perceived as BS and the cost of the SMc update, I decided to upgrade to a Benchmark system, which has both manufacture & external testing data to prove its credo. I would recommend not putting your money into another rebuild. Start anew.

Agreed. Like I say, a well-respected designer, but I also got the audio-foolery feeling with the Gravity Base, and then looking at the wooden disc that makes indescribable improvements..that you can't really prove. I've thankfully been less apt to buy into this stuff than some, but this site has helped solidify my staunch opposition to it now. If it really works you ought to be able to prove it.

VTV has a 30 day trial. Just buy one and see if you like it. If not, return and maintain your current amp.

Yep, I see that and that was what I was considering. I'd pull the trigger on the Benchmark right now but don't have the funds. The Purifi, if as advertised, seems like a giant killer. Just placed the order.

Thanks all, appreciate the comments and suggestions very much.

 

[3125b]

Stereophile measured the DNA-1 back in '92: https://www.stereophile.com/content/mccormack-power-drive-dna-1-power-amplifier-1992-measurements
FR is flat, crosstalk rather bad but not terrible, SINAD is meh.
It should be good enough to not be noticeable in a negative way, but objectively far from impressive by todays standards. I doubt you'd hear a difference to the Purify in a blind listening test.

 

[Rockdog]

Stereophile measured the DNA-1 back in '92: https://www.stereophile.com/content/mccormack-power-drive-dna-1-power-amplifier-1992-measurements
FR is flat, crosstalk rather bad but not terrible, SINAD is meh.
It should be good enough to not be noticeable in a negative way, but objectively far from impressive by todays standards. I doubt you'd hear a difference to the Purify in a blind listening test.

It was a decent amp at the time, though not stellar in testing, and I bought it primarily from that review. I always heard it as "warm, sweet, punchy, and imminently musical", as the review stated, demonstrating that subjective impressions and creative writing have a long-lasting effect on the perceived experience. I still think it does have that character, but comparing it will be interesting. Listened to it for 30 straight years without auditioning any other.. However, I think you're incorrect.

I'm sure I'll hear multiple veils lifted, a better sense of rhythm and pace, greater mid-range clarity, more sparkling highs, and of course deeper, tighter, more engaging base... or-yeah, bet you're right, probably wouldn't be able to tell in a blind test unless it's degraded to some degree, or maybe a SOTA new amp does have a distinctively different character...I'll post my impressions here, but of course they'll be just that, impressions. I'll put the DNA in storage and keep it as a backup for if and when the Purifi dies, hopefully, another 30 years.

Cheers

 

[Rockdog]

Thought I'd follow up here after a week with the Purifi amp in place of the old McCormack beast. Subjective if course but I did some A/B as best as possible. With a second set of speaker cables able to make the switch in about a minute...sighted of course, level matched only by ear, and not blind, so for what its worth..

First impression was the Purifi seemed a bit dry but more detailed and precise. After a few days though, not sure I'd go back. The differences are subtle and I would probably lose a double blind in telling them apart. At 150watt rms rating into 8 ohms for the McCormack, the Purifi is a stronger and louder amp and very loud it sounds crystal clear where the old amp seemed to muddy a bit.

What's a revelation is how small the Purifi is, and how cool it runs. Amazing after decades of a room heater. Bottom line, glad I did not spend double to rebuild the old one. The future is here!

 

[Seattlerepairhobby]

I have 3 Mccormack DNA-1 and I upgraded / recapped for two of them to be twin deluxe poweramp. All with MP resistors and KG capcitors. Sound are amazing after break-in for two weeks.

 

[pcv57]

I just picked up a DNA-1 that needs repair. If I send it to CJ in Virginia it will cost about $1600. I believe they replace the entire circuit board and caps.
If it goes to McCormick Audio in CA, looks like it will be $2600 a $3100 depending on whether I gave with the gravity base option.
If I choose to go the “cheaper” route and send it to CJ, does this improve the sonic performance or am I just getting a renewed amp?
I know there are a lot of varying opinions but any recommendations would be appreciated.

 

[3125b]

does this improve the sonic performance or am I just getting a renewed amp?

Wouldn't it be a bad rebuild if it did change the amps output significantly?
I wouldn't spend that much money on rebuilding a very mediocre amp when I could get a better one for less.
Check with the company what it is they actually do and how they would describe the likely effect.

 

[Martini]

Since Conrad-Johnson is primarily a tube based audio manufacturer, any “improvements” outside of continued service life would likely be subjective. SMc would make grandiose statements about sonic improvements entirely subjective. Both will prolong the life of the amplifier, but I don’t believe it is worth the cost. You could get a SOTA amp like the Benchmark AHB2 or a couple D-class amps, like Buckeye Purifi for the rebuild cost, and have an excellent sounding amp with the measurements to prove it.