Hi Guys -
As has been pointed-out by several posters, I am woefully behind in updating the information on my website. I do apologize for that, but will plead extenuating circumstances - I've got way too much work to do! Anyway, I promise I will try to get the website more up-to-date soon, and in the meantime you are welcome to call with your questions.
The "ARC" (Advanced Rectification Circuit) upgrade is a fairly new option, as I just finished the development early in the year. I don't want to give away too much , but it is a new approach to doing the DC smoothing following rectification (or a new twist on an old idea). It makes a very nice improvement in overall performance, PRAT, and individualization through the midbass and lower midrange. There are 2 variations: ARC-1 and ARC-2 (used at different points in the power supply system). The ARC-2 can be installed in any of the amps I currently upgrade, and the ARC-1 is applicable to the DNA-125 & 225 only. Cost (as part of an upgrade) is $250 for the ARC-1 and $500 for the ARC-2.
And finally, since Zaikesman asked about the DNA-500, I have (reluctantly) decided to drop this one from the upgrade list. It is simply too costly in terms of time, and I have been devoting most of my time (what little I've got left!) to finishing my new preamplifier (and it's getting close!).
Call me if you've got questions.
Best regards,
Steve McCormack
www.SMcAudio.com