SQ: Sony SQD-2020 SQ Decoder

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Quadrockasaurus

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If you have any more photo's or comments to make on this Quadraphonic unit please feel free to post them in this thread....:)

Sony SQD-2020 SQ Decoder


Rarity: SCARCE
Average Sale Price: UNKNOWN


Ad below from January 1974
Sony SQ2020 Quad Decoder Jan'74.jpg
 

Quad Linda

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SQD-2020, the quintessential SQ decoder. One is staring at me across the room. The meters look very cool with my SH-3433 scope above it. Even when I get a Tate, I will NEVER sell this piece. SQD-2020, CR80-DSS and 4DD-5 are the pieces that define an era. All three are attached to the B&K preamp on my main system.

Even though I sold this stuff back then, I don't remember SQA-100. It looks like an SQA-200 on its side. Never sold either one. We didn't stock them. Didn't sell many SQD-2020's, although I sold more of these than any outboard decoders, except the Marantz plug-in modules. I own an SQA-2B and an SQA-1. I also have an SQD-2010.

Thanks for posting this, Quadrockasaurus! It's bittersweet to see these ads. Quad had such promise at that point.

Linda
SQueaky Wheel
 

Disclord

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The 2020 was the first "advanced" SQ decoder released to the consumer market that had both front-back logic and wave-matching logic, which Sony referred to as "Waveform Comparator Circuitry" - in other words, it's a gain-riding "power transfer" unit that raises and lowers channel levels to try and 'hide' the crosstalk introduced by the matrixing. Actually, there was a Full-Logic decoder released right before it, also from Sony, but it didn't get nationwide distribution like the 2020 did, so for all intents and purposes, the 2020 is the "first". The 2020 was so good that CBS used it in many of their SQ demo's. The 2020 is all discrete - there's none of the cheesy Motorola SQ Logic IC's and Sony hadn't finished designing their own SQ Logic chip-set, so the 2020 is, in basic fidelity, wonderfully transparent sounding, especially if you are using it as a 'control center' for other gear like a CD-4 or Tate unit. Plus you get the great VU meters on every input.(note however that the logic system is only activated in the SQ decoding setting - the 2/4 and "RM/QS" settings don't use any form of logic enhancement and so have only 3db or less of inter-channel separation) Also the phase shifters in the Sony's SQ matrix section were done very well and were much more accurate than other companies who usually relied on either Motorola's SQ Matrix IC, which had considerable phase error, or used their own low-cost design - accurate phase shifting didn't come cheap back then and SQ requires it if it's to be decoded accurately. Unlike almost any other Full Logic SQ decoder except the Lafayette's, the Sony's logic never pumps noticeably or causes dramatic image shifting with the logic action - full separation is either audible or the room sounds slightly 'shrunken' as simultaneous sources become predominant but you won't hear the alarming front to back shifts that other decoders could generate.
 

cupboy

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There was an optional wood case for the 2020. It was way too expensive though.
 

Quadrockasaurus

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Thanks for the info and insights everyone.....I was 9 in 1974 so my entire hi-fi system in that year consisted of a $10 pocket transistor radio..:rolleyes:. I haven't been able to track down one of these SQ Units in my neck of the woods...but I'm still looking..!! Its great to have all you guys around to give us all this great info. Cheers.
 

rustyandi

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What about the Sony 2000 decoder I had seen one in Melb.
a long long time ago
I looked the same but I think it did not have the toggle
but a knob to change something
 

Doug G.

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I have an SQD-2050 (2 actually but 1 needs work - the one that looks new, of course). Disclord, did we determine in previous conversations that the performance of the 2050 is close to that of the 2020?

It sounds very good to me and rarely ever pumps either. No meters. A nice compact little box.

The SQD-2020 is another beautiful quadraphonic piece.

There were so many.

Doug
 

Disclord

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I have an SQD-2050 (2 actually but 1 needs work - the one that looks new, of course). Disclord, did we determine in previous conversations that the performance of the 2050 is close to that of the 2020?

It sounds very good to me and rarely ever pumps either. No meters. A nice compact little box.

The SQD-2020 is another beautiful quadraphonic piece.

There were so many.

Doug
The 2050 is only a so-called "Half-Logic" design - meaning Front/Back Logic only - in other words, only Center Front sources and Center Back sources are given any logic enhancement (while almost every SQ album has Center Front signals, such as a vocalist, Center Back signals rarely exist in SQ and were encoded on perhaps 3 SQ albums - the most notable being Omar's voice in 'You are woman..." on the motion picture soundtrack to "Funny Girl" - Until the "London Box" encoder was developed, CBS strongly discouraged use of the 'center back' position because it cancelled out completely in mono; unfortunately, by the time the London Box was available, SQ was all but dead and I don't know of any commercial releases that used it, although it was used in some SQ FM broadcasts in conjunction with the SQ Ghent Microphone)

Anyway, back to your 2050 - the Front-Back Logic gives about 10db separation between Center Front and Center Back - the corners are given no front-to-back enhancement so they have only the standard non-logic matrix performance of 3db separation, max. That's why Wave-Matching Logic was developed, to recognize corner signals and enhance them - when combined with the Front/Back Logic you had a 'Full Logic' decoder that could enhance the corners as well as the front and back center signals (Center Left/Right side signals never received any logic enhancement until the Fosgate Tate II 101A decoder was developed). If you have an SQ test record or an SQ album that has clearly identified corner signals, using the 2050 you'll hear severe crosstalk from Left Front into Left and Right Back, and vise-versa. Only centrally located phantom images will be given any enhancement. So the 2050 isn't in the same category of performance as the 2020. The reason you don't hear any logic action is because CBS/Sony kept the amount of enhancement low in front-back only logic decoders to avoid that kind of artifact. The 2050 probably sounds and decodes better than other Front-Back Logic decoders available then because of Sony's excellent SQ phase shifters and Sony's solid circuit design/engineering (which they have now lost in the analog domain).

Here's a diagram from a CBS AES paper of the performance of the various SQ decoders/Logic systems - the L to R surround channel separation for "real world SQ Front/Back, Wave-Matching Logic and Vari-Blend decoders was NOT 20db as shown in the graphic - it was typically around 14db. If your instruction manual for the 2050 lists channel separation, note the Left to Right Surround specs. On the 2020 it's only 14db. (BTW, the V-B means Vari-Blend and it took the place of Front-Back Logic). The Paramatrix Logic specs reference basically any 'phase cancellation' type decoder such as the Tate DES, Shadow-Vector and CBS own Paramatrix decoder.
 

hyounce

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I recently came into possession of a Sony SQD-2020 decoder that I would either like to add to my collection of '70's Sony gear, or sell to an interested buyer. Don't know if it works, as I have never attempted to integrate it into my system. I was told that the unit is fully functional, although it is missing the metal cover on the "SQ" push button and the knobs for both the "POWER" and "MONITOR" switches. If someone has these knobs for sale, or would like to make me an offer for the unit "as is", please let me know.

Henry Younce
Julian, CA

Sony ST-5000FW tuner
Sony TA-2000f Preamp
Sony TA-3200F (2) Poweramps
Sony TA-3120A Poweramp
 

jefe1

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I have read that the Sony 2010 has better components in it. Linda, have you compared your 2020 and the 2010 for any audible differences?
 

Quad Linda

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Sadly, Jefe, I've owned them both forever, but never A/B'd them. They're attached to different systems and I'm lazy these days. I A/B'd my Marantz SQA-2B to the SQA-1 briefly when I upgraded in '76 ish. Yes, the SQA-2B sounds better. I purchased the SQD-2010 from a customer who was getting out of Quad in early '75 for $25. Like my Onkyo TX-SR504 at $39, it wasn't needed, but was too good a bargain to pass up. He had only used the 2010 for a few months. The SQD-2020 was bought on accommodation for $100 ish.

SQD-2020 is so much more than a decoder, of course. It's also a control center, tape loops, rear preamp and has pretty meters. These days, it's just one of 6 black boxes attached to my B&K Reference 50 surround preamp, along with a JVC 4DD-5, Russound QT-1, Ortofon T 20, Technics SH-3433 and dbx 224. The SQD-2010 is attached to my Denon AVR-3801, along with my Technics SH-400. I use the SQ decoders for matrix records only, not for synthesis. I prefer synthesizing within the respective preamps or receivers, in order to maintain a shorter signal path.

Disclord could probably compare the chipsets and decoding differences. The SQD-2010 was touted as being full-logic wavematching, though I've had service techs tell me it isn't.

Next year, I plan to buy either a VPI or Rek-o-Kut w/an Ortofon moving coil, a VPI record cleaning system, Lou's demod, a Tate, a Sansui decoder & Oppo BDP-95.

There were some better SQ decoders released later, but the SQD-2020 is the prettiest decoder ever made. The SH-3433 scope atop it make for a gorgeous couple. My modern gear performs better, but the vintage '70's gear looks far more impressive. Just a woman's opinion.

Linda the Donnamatrix

I have read that the Sony 2010 has better components in it. Linda, have you compared your 2020 and the 2010 for any audible differences?
 

pmeyers

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Hello,

I have just joined the forum and came across this thread that mentions you have both owner's and service manuals for the Sony SQD-2020.

Would it be possible to obtain copies from you? I'm certainly okay with a fee if thats required.

Please let me know and thank you for your time.

Phil
 

Q8

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I too would like to have a copy of the owners manual.
 
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