I am so glad to see this Quad email from the QQ. I own a Sansui QRX 7100 and 3500 and 2 Lafayette LR5000s all with JVC outboard CD4 Demodulators all fully restored. Actually the 3500 has a Panasonic CD4 outboard. There is a place in Houston run and operated by one person who knows quadraphonic systems extremely well and really knows what he is doing. The place is "Save on Sound" a very busy one man show. Takes a while for repairs and restorations but is worth it because the outcome is perfect to original specifications. I also have an extensive collection of Japanese CD4 recordings such as Rare Earth, BTO, Sunfighter, Bark, Moody Blues, Possum River, Hot Tuna, etc. The Japanese did an absolutely wonderful job mastering their CD4 recordings and pretty good with QS and SQ.