Sony SQ Decoder SQD-2020 solid state quadraphonic decoder. (1973-76).
The Sony SQ is in very good condition with only very minor handling wear, the grey cabinet has aged with some discolouration. All inputs work although I must confess I have no idea how to set it up! I bought it some while ago and now have so much "kit" I do not have the time to find out, I did find info on google and some youtube stuff.
Stand alone SQ (Stereo Quadraphonic) Decoder; SQ, Regular Matrix and Discrete Modes
2 and 4 Channel Tape Monitor
4 Illuminated VU Meters
Rear Tone Controls
4 Independent Level Set Controls
Master Volume Control.
"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."