Quad Bob

Quad Bob tells about an ultra-rare quad goody


I just posted a picture of a REAL quad rarity in the photo section for you guys. The Sansui QSD-1000 decoder/synthesizer. And, as you whet your whistle over the picture….here’s the REST of the story! (As best we know!). The Sansui QSD-1000 was only produced for 1 production year in 1982. Supposedly, Japanese Quadraphiles were highly upset when Sansui joined the masses and bailed out of quadraphonics, dropping production of the QRX-9001 in 1979. They demanded that Sansui make an “ultimate” statement of their Vario-matrix QS decoder/synthesizer…price no object, just give us the best! Sansui responded with the QSD-1000, hand made on a pre-order basis. The decoder was made without ANY phase shifting capacitors in the circuit. Instead it uses FETS (field effect transistors) running off the same Sansui proprietary QS decoder chips found in the QRX series receivers and QSD-1/2. Adding Alpine pots, and high quality caps where required. The finish is gloss piano black with rosewood side panels. The front LEDs and lettering are all in gold and GOLD plated RCA connectors on the rear (pretty rare in 1982!). It was designed strictly for the Japanese market (operating on 100VAC at 50hz). So, how did it get to the US? Thank Dave Vaccaro of Chicago Audio. Sansui brought a QSD-1000 to the 1982 CES show in Chicago. Home theater was in its infancy and they thought the QSD-1000 “might” be marketable. After arriving at the CES, they then realized that virtually no one was promoting/showing Home Theater equipment…so the QSD-1000 and its piano-black display stand were relegated to an area “behind the curtain”. Along came Dave…a longtime quadraphile and major Sansui fan! He happened to spot the QSD-1000 out of the corner of his eye, and immediately went to examine it further! He asked how much…and when could he get it! The response was…..”Sorry, not available, not for sale, not designed for the US, no market”!!! Dave KNEW where the market was!!! He managed to get to Sansui’s Top man at the show, and after much arguing…….”It won’t work in the US”….”I’ll adapt it!”, “Too expensive”…..”not for us!!!”, “must be pre-ordered”…..”I’ll order 12 RIGHT NOW!” Dave got Sansui to accept an order for 12 of the QSD-1000. After the show and before delivery….he pre-sold all 12 to long-time quad fans, purchased and assembled a voltage transformer for each to convert to our 120vac, and when they arrived placed another order for 10 more. After he had those sold he tried to order 10 more and was told by Sansui……”no longer available, the production line is closed”. So, 22 QSD-1000s made it to the US thanks to Dave. Nick Perragini managed to find 2 more through either Japan or Japan via Europe where it wasn’t released either. So, that makes 24 of them known to be in the US. No one knows how many were sold IN Japan, but the guess is less than 100 total. All 24 of them in the US are accounted for….Dave Vacarro still tracks each of them, which isn’t hard as they have hardly ever changed hands. Among the quaddies here on Yahoo, I have one….I know Tad (Quadtrade) has one…..anyone else???? “Quad” Bob

So if I can play a quad LP on a normal turntable and run it through the decoder and get neat quad (oooh, yes I can!) can I dub that LP on regular stereo equipment onto a stereo cassette tape and then run that cassette copy through the decoder and still get quad out of it? Are there any commercially made stereo cassettes out there that have quad info on them that I should be aware of? And finally, if the Impulse LPs are supposed to be quad, does that hold true for the 8-tracks? e.g. If I play my Alice Coltrane

Journey in Satchidananda stereo 8-track on a regular 8-track player hooked up to the decoder’s LP inputs will I maybe get something quad out?


The answer is basically Yes AND No! As SQ/QS/other Matrix (NOT CD4) encoded material IS two channel compatible, the easy answer is Yes ANY format…lp, tape, cd, stereo VCR will decode through the decoder. However, for most practical and correct signal purposes the answer is No. The reason?

Tape decks (8-track, cass., reel) need to be calibrated for “azimuth” alignment of the heads. In the early days of quad production they found that even slight azimuth misalignment affects the phase relationship of the signals…. and thus the quad encoding. It doesn’t take much difference either, they found that even their production duplicators varied enough to cause

problems. Because of this few Quad titles were released “encoded” on tape. However, some producers DID release quad encoded tapes….notably Angel Classical and Ovation. Also, as the same “master” tapes were used others were released with the encoding intact….like ABC/Impulse, the Columbia “quad only” titles, and others I’m sure. So, will these decode through a decoder….yes, will they be “right” as intended…maybe, maybe not. Now, there is a slight exception to all of this… if YOU record a Matrix quad title on YOUR cassette deck, and play it back through THE SAME deck…it should be fine! The reason is that the azimuth should be the same on both record and playback. This can be affected over time if your head alignment changes. 8-tracks are the worst for this as the head has to move so much/so

often! I myself dub to a cassette deck with a Fixed 4 channel head…..the “head” doesn’t have to move thus lessening the chance of drift and it plays back perfectly fine. But, if I loaned you one of my cassettes it might not! Finally, on your Alice Coltrane question….the answer is NO….Not all the Impulse titles were encoded and that one isn’t on the list….is it marked quad?

Hope this helps, “Quad” Bob

Matrix decoder advice:

First of all,what matrix are you interested in? If all of them an older Sony outboard would probably serve, you can always improve equip as you go. Also, an Electrovoice “Universal” EVX44 would handle all matrixes. Note: no SINGLE decoder will decode all matrixes well. Sansui made the best (and only) decent QS decoders, and Fosgate/Tate and Columbia made the best for SQ.The rest offer differing degrees of performance for any matrixes.


4 comments on “Quad Bob

  1. David says:

    Ref: Sansui QRX-7001 4 ch Quadraphonic receiver

    Tested both ch’s working, but the sounds is very low audio?
    Even at FULL volume, is very very quite. Maybe the amplifer section is blown? All fuses tested good. Any help from QuadBob

  2. obbop says:


    Best place for any/all quad-related info, questions, etc.

    Use “search” feature for postings regarding Quad Bob.

  3. HiFi1991 says:

    “The Sansui QSD-1000 was only produced for 1 production year in 1982.”

    I think, this QS-D1000 was assembled in Dec. 1985:

    And this QS-D1000 should be assembled in Jan. 1986:

  4. obbop says:

    Thanks for the pictures.

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