2. amps-preamps
  3. 181722-96

Don’t buy used McCormack DNA 1990s amps

This is a public service announcement.  There are some yahoos on other sites selling 1990s McCormack DNA amps, sometimes at ridiculous prices.  While they’re great amps, and I happily owned a DNA 0.5 RevA for 20 years, they’re all gonna fatally fail.  Why?  Because their input board is at the end of its useful life, and when it fails your amp is dead and not repairable by anyone — not even SMcAudio.  It’s a boat anchor.  The only option is to sell it for scraps or get an SMcAudio upgrade that’ll cost around $2000.  Given my love of my amp I chose to do full upgrades given what else I could’ve gotten for the same same price and just got it back and will forward thoughts if anyone cares.  But the purpose of this post is to warn off any prospective buyers of a circa 1990s DNA amp that it’ll fatally fail soon, so unless you get a great price and plan on doing the SMcAudio upgrades just avoid these amps on the used market.  You’ve been warned. 

soix
soix OP
9,730 posts
 

@stevemcx Thanks for chiming in here Steve — most helpful.  Not to get too much into the weeds here, but I’d think since I assume both the DNA-1 and 0.5 input boards were designed around the same time and assuming they’re more alike than different, what makes the DNA-1 board more prone to failure, or, what makes the 0.5 board less prone to failure?  Just curious because that’s very interesting.  Sorry to take your time, but thanks for any thoughts. 

stevemcx
166 posts
 

The DNA-1 design predates the DNA-0.5 by around 2 years. I made several changes to the circuit design for the 0.5, and its circuit boards were a bit smaller and not as complex as the DNA-1. There is a central ground area on the DNA-1 board that is the location of most of the through-plating failures, and this was done differently on the DNA-0.5 board. In the end, the original DNA-0.5 board is a bit smaller, less complex, and less prone to through-plating failures - although as Pat has pointed-out, we have begun to see these failures in the past few years.

I designed an all-new circuit board (called the R3) a few years back when it became clear that working on the original boards was a losing battle. With some careful layout it was possible to make one board that fits both amps, so that was a welcome bit of efficiency. In addition, the quality of the boards we get now is exceptional, and better than the originals.

Steve M

arcticdeth's avatar
arcticdeth
1,572 posts
 

All upgrades still available for the the dna750 monos.

LD-2 ?

not for the UDP-1?

 

stevemcx
166 posts
 

Thanks for your interest. Yes on the LD-2, but no on the 750 monos and the UDP-1. We have never done upgrade work on the UDP-1, but we have done a few pairs of the 750 monoblocks in the past, but no longer. Like the DNA-2, DNA-500, the 750 monos are just too big and heavy for an efficient workflow. They eat up too much time and are too expensive to be practical.

Steve M

arcticdeth's avatar
arcticdeth
1,572 posts
 

#@&&%%**#$

Damn, I spoke with you and Pat about a year ago, and was given a price for capacitor upgrade, and a bunch of other stuff. 
  Fingers crossed for reliability. 
never had good luck with my gear. 
 

I will have to add 750s’ to my kids nightly prayers.

well, if and when there is a breakdown, I will give a call and ask if you have the time for gold+ revision. 
 

cheers Steve, great week. 

More to discover