McCormack DNA-1 Gold or DNA-225

dyl71 - exciting stuff. Enjoy your "new" amplifier as I am sure it will sound great. Based on your description, it sounds as if you probably had Steve install the Plitron transformer, which I understand should improve dynamics even further. Since you probably discussed the upgrades in detail, you would know whether the input transformers were part of the upgrade, which should be true if the upgrade included balanced inputs. In any event, the stock DNA-1s came with an input impedance of 100K ohms and the upgraded DNA-1s (either monoblocks or with balanced connections - anything where Steve added the input transformers) have a much lower input impedance of 10K ohms. If you don’t have the input transformers, then you likely retained the higher input impedance.

Below is a link to an Audiogon thread where Steve explains this situation. If you have the lower input impedance, you need to be more careful about matching with a preamp and I have found that most (but not all) tube preamps and most (but not all) passives will probably not mate well with the lower input impedance. However, just about any SS preamp, passive using autoformers, and Steve’s own TLC-1, which is a unity-gain, buffered preamp, should mate very well. Steve offers upgrades to the TLC-1 unit that turns a very good sounding older preamp into an excellent sounding preamp regardless of age and virtually regardless of price, IMO. I have tried/owned around 20 well-regarded preamps (tubed and SS) in the $5-12K range, and my upgraded TLC-1 with outboard power supply beat all of them on sonics, ease of operation and just about any other parameter...except having a remote, which I do not miss at all. I have heard he is doing very good things with the micro line drive preamp also but not quite to the level of what he can accomplish with the TLC-1.

Link:
https://forum.audiogon.com/discussions/preamp-impedance-mismatch-with-mccormack-dna2/post?highlight=dna-1%2Binput%2Bimpedance&postid=732291#732291

Good luck with your upgraded DNA-1!

@mitch2 
Pat ( I don't know his last name) has been my contact since I contacted SMcAudio. I don't know about Kris, but maybe he isn't on the phone as much as Pat. Some folks are better at taking calls than others.
@hifiman5 
Yes, I got the amps back a while ago, but haven't put them to their paces, yet. I needed to have Bob Worzalla at Sound Anchors make me a pair of stands to hold my subs and amps (besides the McC, I have a pair of Atma MA-1's- for my winter listening as they get way too hot).
Steve and Pat knew I had Atma's and gave it their best go, given my budget.
I will post my findings when everything gets put together, which includes not only amps, but new speaker cables, and Equi+Core power conditioners.
Yes, I know I am ill.
Bob

Hi Bob, 
Good luck with the DNA-1 monos.  Please do let us know what you think of them, and how they compare with your MA-1s.  Steve and his crew do great work and he certainly pays attention to the details and does all he can to meet the expectations of his clients.  

Well, the amp arrived a few weeks ago...I've only managed to get about 10-15 hours of listening so far based on a crazy work schedule.

First off, this a finely crafted amp. I also didn't expect the size as I've only seen some pics of it, fit and finish are top notch.

The first few familiar recordings I played, I was immediately taken in by the smoothness and clarity this amp provides. Granted I need to give it time to bloom, but so far it's taken the soundstage to another level.

All the instruments and vocals seem to have increased clarity in the quiet passages, the highs are not harsh in the least bit, very smooth and natural. The light, delicate taps of the ride cymbals have pronounced decay time, it's quick when it needs to be, and slow and smooth as well when required.

I was able to hear the wood of the guitar at times before, depended on the recording, but for the most part it was in the background, albeit slightly hidden. Now it's there and I will contribute that to the lower noise floor and just the overall low-level dynamics this amp puts out.

The bass is full and tight, the amp just doesn't seem to run out of steam and nothing gets smeared along the way when you turn it up.

Overall, it's like a big, dark, liquid hole in my listening room filled with holographic instruments. The big (well-modded) SDA's already provide a huge soundstage, but the DNA allows me to step right in front of it. I won't say it's like lifting a veil, it's more like being right up to the stage. Everything appears larger and clearer,  but not overwhelmingly so, this amp just seems to do everything so well. 

I would like to swap the fuses for some Synergestic red or blue in the very near future after it gets some hours on it, but for now I want to let it open up first.

I finally got my DNA-1 monoblocks set up and burning in as I write.
I concur with dyl71, the sound is very clean and holistic.

My only problem is that the Vandy crossover for my 2wq subs only goes to 22K ohms in balanced. I think I need a lower setting. When I get some energy, I'll try them with the RCA cables and RCA xover, which goes down a bit more. This will probably be a new post comparing my experience with Atma-Sphere, McCormack and Ayre.
Re: Synergistic
I recall Pat mentioning how much better the amps would sound using them. I can't remember which one- Red or Blue.
B