Tweakers' Asylum

RE: McCormack DNA-1 Deluxe Schematic/Service Manual..

76.119.73.28

teknofossil

In Reply to: RE: McCormack DNA-1 Deluxe Schematic/Service Manual.. posted by Steve McCormack on March 15, 2009 at 13:58:15

Steve,
I have been curious about a circuit that you included in the MAP1, namely a circuit called the "Ambiance Retrieval Mode" (ARM). One description of it that was published in a audio mag reminded me of the original Dolby surround, in other words, right, left and center channels with a (L-R?)differential signal being sent to the surround channels? Is there any chance you could offer some insight into your circuit. Lastly, the last I read about McCormack Audio you were still with the firm (Conrad Johnson). Are you now independant again?
-T

Edits: 03/16/09 03/16/09

Follow Ups:

RE: McCormack DNA-1 Deluxe Schematic/Service Manual.. - Steve McCormack 13:17:00 03/19/09 (2)
Hi T -

Sorry for the late reply - I've been out sick for several days. You are correct about the ARM circuit - it is a variation on the original "DynaQuad" passive matrix decoder. But I'm afraid that is all I can tell you. It's performance is dependent on the nature of the source material, but it usually works very well with most stereo recordings.

I have been independent for a few years now, with SMc Audio being my entire focus. McCormack Audio continues to march along, and I wish them all the best.

Best regards,

Steve McCormack, designer
SMc Audio
- RE: McCormack DNA-1 Deluxe Schematic/Service Manual.. - teknofossil 16:21:59 03/20/09 (0)
  Steve,
  thanks for the reply. Best of luck with your new company.
  
  -Tom
- The Ambience Recovery Mode (ARM) of my c-j MET1 produces... - jeffreybehr 14:42:36 03/19/09 (0)
  ...a 5-channel signal from a 2-channel one. It works VERY well with SOME stereo recordings, adding some spaciousness to the (separate) surround channels and to the center channel; these seem to be those that already sounded more natural--that is, that are less multi-mono-miced. Since those are the kinds of stereo recordings I prefer and own, I use ARM while playing most of my stereo recordings. On some stereo recordings, the sound with ARM is worse--more jumbled and less focused.
  
  Written info I have from c-j on the MET1 indicates that several LF 353 opamps buffer the inputs (the left- and right-channel signals) and then create an L&R signal for the center channel, an L-R signal for the left surround, and an R-L for the right surreound.
  -------------------------------------------------------
  Tin-eared audiofool and parttime landscape fotografer.
  http://community.webshots.com/user/jeffreybehr

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