I used to be a bit of a Quadraphonic nutcase about 15 years ago. I've owned and repaired many different quad setups. Here are my thoughts on the various manufacturers and models. I liked The dynaco sca-80q because it wasn't beating you to death with the rear channels like many receivers do. It was a modest and smooth sounding transition between front and rear fields. The early sansui and pioneer units like the sansui qr-4500 and 6500 and pioneer qx-9900 have simple out of phase decoders that make everything feel like a blob of sound. That of course changes with the use of a quadradisc / cd-4 record, but for the most part I found these boring. The pioneer variants are much more difficult to work on and have many noisy transistors and bad capacitors to replace. The qx-949a which was a short lived unit after the qx-949 was pioneers attempt at a decoder with full logic, which was a massive improvement over the simple out of phase decoder, but sansui already had a full logic system which sounded better than the Pioneer by 1974 in the qrx-7500a. Pioneer also had discrete separates for Quadraphonic - the qc-800 preamp and Qa-800 amp. Pretty to look at, but simple decoding made them expensive and unpopular options you don't often see. The 2nd gen sansui (qrx) series receivers are much better and produce a soundfield that sounds natural to me, although like the dynaco, some recordings sound better set to stereo. I've sampled both a qrx-7500 and 7500a, and the better logic in the A revision decoder makes 2 channel synthesization into quad sound more like discrete. The last generation sansui quads (qrx-6001 through 9001) are bay far superior in decoding and synthesizing 2ch into 4. However I've owned three 9001 in my lifetime and the continuing problems with double sided boards became annoying. The 7001 is by far the best choice between sound and reliability. The last gen decoders can be modified for fairly high channel separation (about 40db) and will decode dolby pro logic well. The marantz units I found to be uninspiring. Even the 4300 and 4400 with an sqa-2b made more power than they did a good listening experience. Again, just seemed like a blob of sound unless using encoded material. However, they are the most beautiful looking. The more rare units like the sony sqa series and the even more elusive kenwood Quadraphonic receiver were nothing to write home about. The ICs in the sony decoder are highly prone to break down and failure. I've never seen a kenwood quad that didn't have a noisy decoder. I'd like to find better examples to test, but they are rare to find
@FluxCondenser
3 жыл бұрын
Jordan, thanks so much for taking the time to share your observations. Much appreciated, it makes for a nice starting resource for others looking to get into the quad.
@darthbubba866
3 жыл бұрын
First! I used to put a potentiometer in the circuit so I could dial in the amount of rear ambiance I wanted. It was fun to have people listen to it then shut off the back speakers suddenly - to a one they all asked for the back speakers to be turned back on. Many also asked me to come put together the same setup for their stereos.
@FluxCondenser
3 жыл бұрын
Darth, thanks for sharing that. A potentiometer between the rear speakers is a common addition to the Hafler circuit. There’s lots more info online about how to setup a simple system as you did, and I encourage other viewers to do some research and give it a try. I think they’ll find, as you and I have, it can be pretty impressive.
@autodidactic278
3 жыл бұрын
I collect quadraphonic equipment. I have the Dynaco quadaptor. I recently recapped my EVX-4 and plan on doing the same on my Sanyo DCX 3300KA receiver.
@tremolux13
3 жыл бұрын
Just came across your channel! Good stuff, just subscribed!
@FluxCondenser
3 жыл бұрын
Thanks, Jesse. Glad to have you aboard. Hope to have the final episode (P9) of this series up within a few days. I’ve gotten a bit behind due to spending more time mountain biking, and just recently from my second COVID shot which really knocked me on my butt for a few days.
@Elektronenregen
3 жыл бұрын
Very interesting video! And nice radio collection you have there :). I especially like the Braun RT 20.
@FluxCondenser
3 жыл бұрын
Thanks, so much, glad you enjoyed the video. Yeah, I absolutely love that Braun. Talk about an ahead-of-its-time design. And it sounds (almost) as good as it looks.
@stuartmarks8844
3 жыл бұрын
Specific quadraphonic encoding/decoding in a matrix format or 4ch discrete almost sent the major labels to the poor house (according to them).They should have just stuck with this format. A stereo signal delayed 20MS or so then sent to another stereo amp and speakers will work with Stereo CDs from the 90s of Pink Floyd Lps since the stereo mixes retain a hidden signal of sorts as if they merely folded down the quad mix. I.e. there won't be a slap back delay as with non quadraphonic releases. Jeff Beck Truth works as well but that record might be a dynaquad...(not sure.The engineer clearly weaved an outboard out of phase effect into the whole mix somehow.)Glad I found this channel. Thx for the work you put in. Really excellent
@FluxCondenser
3 жыл бұрын
Thanks, Stuart. It really is a shame what happened to 4 channel music. Music companies, engineers and manufacturers have been trying to convince us we need more than simple stereo for decades, but nothing’s really stuck. With quite good timing, it’s interesting to see Apple, for example, is now incorporating Spacial Audio into their music offerings, a two-channel system which tricks the ears into hearing surround sound. A similar, but more sophisticated approach to some things we’ve seen before, but with the added trick of head-tracking. Take care, and thanks for your excellent input.
@gene8933
2 жыл бұрын
I had high end Quadraphonic system back in 70s with 3 different decoder formats SQ Quadraphonic, Matrix decoder,and Quadraphonic record decoder,which accurately decoded playback the best. Optimum placement for rear speakers was painting toward your ears.The front wear towed in toward your ear like a stereo setup for best sound.
@Musicradio77Network
3 жыл бұрын
I only have my Sony SQ Decoder which is a SQD-1000 where it decodes SQ matrix along with a Sony Integrated stereo amplifier and an ElectroVoice EVX Decoder and it still works and sounds amazing, and it’s Dolby Digital 5.1 compatible. I’m watching “Space Jam: A New Legacy” right now and it will sound great with my old SQ setup when setting on an SQ mode.
@MODAC
3 жыл бұрын
Good video. Enjoyed it.
@FluxCondenser
3 жыл бұрын
Thanks, David. Much appreciated.
@billinudgelexhaust138
2 жыл бұрын
Try The Lady Don't Mind by Talking Heads in Quad it is the most immersive piece of musical genius with the sound bouncing from every direction.
@montech5647
2 жыл бұрын
Fantastic video and new subscribed here :) Question: is that 10 ohms resistor at 2:18 a fixed value? Depending on the room size, can it be adjusted to, say, 4.7 or 22 ohms? And finally what`s the wattage for that resistor? Thank you a million!
@FluxCondenser
2 жыл бұрын
Yes, that’s R47 which is a 10 ohm, 10 watt, 10% resistor. In this unit, it’s a fixed value, but yes, in a Hafler circuit, this value could be adjusted. Just make certain you stick with at least a 10 watt resistor and yes, you could use a variable resistor (potentiometer) as well.
@aTrulyPowerfulSpirit
2 жыл бұрын
I have had a Telefunken late 70s "quad" system for years but I never set it up properly for this. I think I will give it a try.
@FluxCondenser
2 жыл бұрын
Try it, you’ll like it ;-)
@lapeercharlie8691
6 ай бұрын
What would happen if you placed the "rear" speakers up front, next to the front speakers? I wonder if it could enhance the overall impact, without messing up the "imaging".
@JayRudko
3 жыл бұрын
Have you heard the Involve Audio Surround Master v.2? I'd be interested in how you feel it compares to the Logic 7 you've been listening to. It also decodes the SQ. and QS with very high separation. It's ability to create surround from stereo is amazing.
@FluxCondenser
3 жыл бұрын
Haven’t heard about it until now, Jay. I’ll check it out, though. Thanks!
@akabang2
Жыл бұрын
No where on the web are there any samples of the Hafler effect. Even your demo is at most a half second. Is there something we should not know?
@paulinboston
2 жыл бұрын
Sorry, late to the party. Nice video, but what about the synergy. After building this amp, I would expect some mention of the interaction between the A25s and the Dynaco SCA-80Q amp. Can the transistor dance with the A25s.
@FluxCondenser
2 жыл бұрын
What’re you smoking, my friend?
@rafaelvaca1837
3 жыл бұрын
gordon lightfoots quadrophonic lp sounds awesome.
@FluxCondenser
3 жыл бұрын
Haven’t heard that in quad. Thanks for the suggestion.
@tabbycat8511
Жыл бұрын
Um … no. Surround sound in the movies did not start in the “late 80’s.” Started in the 50’s and was well active in thev70’s. Those “gimmicky effects” from quadraphonic sound are very popular today. Most new releases are now mixed in Dolby Atmos using many of those same effects. And many original quad mixes are out as Dolby Audio.
@tabbycat8511
Жыл бұрын
“I prefer the 60-year-old 4D.” “I prefer the 60-year-old 4D.” “I prefer the 60-year-old 4D.” “I prefer the 60-year-old 4D.” Oops.
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