McCormack DNA 500 vs DNA 225 upgraded

In my above post, I reference a thread which should have been titled:
"McCormack DNA-225 Platinum Edition Upgrades"
(without the word "amplifier" after it)
In that thread, the reviewer/poster states;

I would recommend a transformer-based passive or very neutral tube pre with this amp so that the full luster of the DNA-225 can be realized. In original configuration (100Kohms input impedance) the DNA-225 was a bit particular about volume control. While a high quality and finely stepped attenuator is still crucial, in my mind, it is not as much so given the new input impedance of 10Kohm.

Not quite sure what he is getting at regarding volume control, but his post implies the upgraded DNA225 may have an input impedance of only 10K ohms, which would restrict the preamps you might use to those having output impedance of less than about 500 to 1,000 ohms across their bandwidth.

Also, there used to be some posts around here from someone who had their DNA500 upgraded, although I could no longer find them. I know the DNA500 upgrades are not posted on the SMc website, but I believe there may be a few things Steve can do to improve that amp sonically, and also to provide a higher input impedance by using transformers. If that is a direction you want to go, you should check with Steve/SMc.

Thanks for the input.

Heat could be an issue as the equipment is in a cabinet. I could add in a fan if I had to.

My current preamp is actually a digital processor, an Anthem D2 with Arc room correction. I am not sure how this would match impedance wise, (I am a complete novice at this area). Steve McCormack suggested that I also add in a preamp though.

As to matching either amp for sound quality the equipment I currently have is more digital at this point
McCormack HT5 amp (5 channel)
McCormack UDP1 universal disk (Deluxe)
Anthem D2 processor with Arc
Dennon DVD 3800 Bluray
B&W Nautilus N804 fronts, HT2 ctr, SCM surrounds
HD DTV receiver
Audioquest cabeling.
etc.

Thanks for any suggestions

Allow me to clarify things a bit.

Both the DNA-225 and DNA-500 are fine amplifiers in stock form. SMc Audio offers a variety of upgrade options above and beyond the stock versions for those audiophiles looking for even higher levels of performance. These upgrades are outlined on our website - www.SMcAudio.com.

Although the DNA-500 is not mentioned, I have developed an upgrade package for it and have done several. The owners have been very pleased. Please call for additional details if you are interested.

The input impedance of *all* stock McCormack amplifiers is 100K, except for the DNA-500 which is 10K. For DNA amps upgraded by SMc Audio to include balanced inputs or monoblock configuration, the input impedance is usually 10K (with a small number of amps configured for 40K).

Still_Learning, your Anthem D2 processor will drive any of these amps properly. As I outlined to you in an earlier e-mail, I suggest the addition of a good quality 2-channel preamp simply because I believe it will give you an overall improvement in sound quality. Any regular preamp can be used in a surround / home-theater setup, but this does add a minor (in my estimation) bit of complexity that you may or may not be comfortable with. I mention this because I took sound quality to be your main goal.

With a 10K input impedance, you do have to pay some attention to the output impedance characteristics of the preamp you choose. All solid-state preamps will work well, as will most tube preamps and TVC-type (transformer or autoformer-based) passive preamps. Tube preamps with an output impedance of 800 Ohms or less will work well.

The DNA-225 Platinum will outperform the DNA-500 in overall transparency, low-level resolution and detail, top-end extension, harmonic texture and richness, and toe-tapping musical engagement. Subtle dynamics and inflection are also rendered with greater clarity. The DNA-500 is obviously more powerful, and its sense of authority, bass weight and impact, and sense of ease in driving difficult speakers is world-class.

Neither the DNA-225 or the 500 gets particularly hot under normal use. The 500 runs a bit cooler at idle because it has a lot more heat sink area. The 225 gets rather warm, and if you locate it in a small enclosed space, you might need a small fan to keep the air circulating (but this is rare in practice). The 500 is considerably larger and heavier - check the specs for the details.

As mentioned by other posters, either amp will do a superb job for you.

Best regards,

Steve McCormack
SMc Audio

Steve,
Is there a balanced transformer upgrade for the DNA 750 as well, or is this a true balanced amp design?

Thanks for your feedback,
Stefan

Hi Stefan,

Like the DNA-500, the DNA-750 monoblocks are fully balanced with differential outputs. The input is transformer-coupled using the same circuit as the DNA-500. Input impedance is 10K.

Best regards,

Steve McCormack
SMc Audio