The last SQ decoder made.

[Disclord]

Does any forum member own the Aphex AVM-8000 SQ Decoder? It was, as far as I know, the last SQ decoder made, being released in 1986. In addition to SQ, it also had a Cinema mode. The weird thing about it is that it's a gain-riding logic decoder, not a crosstalk cancellation type like the Fosgate Tate II. Also, it's an Octahedral SQ decoder, with 8 outputs for Lf, Cf, Rf, Rc, Rb, Cb, Lb, Lc and the phase shifters in the SQ section were a precision 10 pole design. Stereophile reviewed it in 1986 and it was rated as "unacceptable" for SQ decoding because, in an attempt to hide the audible effects of the logic, it only applied 10db of gain riding, meaning crosstalk was easily audible, and produced very poor SQ results. In the Cinema mode though it was rated highly, apparently using greater logic action. Aphex replaced it the next year with the ESP-7000 for movies, which dropped the SQ mode and was a true crosstalk cancellation/matrix multiplier design. Unfortunately, the Stereophile review has no pictures of the AVM-8000 - it was tested along with the Fosgate 3601 and Shure HTS-5000. The Shure was the recommended decoder and the Fosgate 3601 was rated rather poorly.

So has anyone seen this odd Aphex SQ decoder or owned it?

 

[tektaff]

Hi There. I have one of these gathering dust. Mine has a few missing chips and without a manual it might be a while before i can let you know if it's any good. As well as that i need to get a load more speakers to try it out with. I'm clueless as to what it does, so your info was the most i've been able to learn sofar.
I did write to Aphex about the unit but sofar no reply.
I have a Tate II to compare it to, as well as a much older Denon decoder with up to 9 outputs, but that's more of an Ambisonics unit than Quad.
Will update as and when but dont expect anything soon.

 

[AlexB]

I have an AVM-8000. For SQ decoding, it is does not offer anywhere near the separation of the S&IC or the Tate. However, it does have one very unique feature: A wireless remote! Might put it on Ebay some day; no sense letting it sit idle.

 

[furui_suterioo]

Found one for sale:

https://www.ebay.com/itm/Aphex-Surr...p2349624.m46890.l6249&mkrid=711-127632-2357-0

 

[Sonik Wiz]

Found one for sale:
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https://www.ebay.com/itm/Aphex-Surr...p2349624.m46890.l6249&mkrid=711-127632-2357-0

Isn't it interesting on QQ how old threads never die? In 2005 Ty posts a note about the Last SQ Decoder & ironically we now have the Surround Master for SQ, but not TY.

The input/output chart is very interesting. Also of note is that the seller says he has no remote, and no idea if it can be operated with out it. The answer is no. Door stop or parts only value in that case.

Ty has said elsewhere the Proton SD-1000 is a circuit clone of the Aphex unit, with upgraded components & enclosure. I have one of those & could not get it do anything expected with QS/RM signals & stereo just seemed like 'ol fashioned Dolby matrix surround with a bit of the front chs mixed into the rear. I never tried it with SQ. Hmmm...

 

[doity]

I want to “Enter The World Of Multi-Dimensional Sound.” Sounds like a fun place to be.