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Quad question

KeithD said:
I believe SQ was Columbia/CBS from what I've read.


This is what I'm probably MOST interested in, synthesized quad from stereo. As I mentioned, I only have one SQ record, which I bought just to see how it sounded with the Pioneer. So, most of what I'm playing is stereo through simulated quad. With the QX-949 it seemed that the circuit was reducing the volume on the rear speakers and adding some reverb to the rear for simulated quad. That's about it. With the QR-4500 I'm hearing the same effect with the addition that there is some sound separation with the simulated quad. I was quite amazed by this and had not heard that with the Pioneer playing the same music.

Interesting that you say the QR series has the best simulated quad. Can you elaborate on that a bit? If that's the case, maybe I should not be looking at the QRX line.
Click to expand...

I had a Sansui QRX5500... truly beautiful receiver. But the Sanyo 3300K/KA quad receiver had better separation & strength of signal to the rears than the 5500. Go figure. I never tried a Sansui QR series. Supposedly, the QRX was a step up from the QR, right?
 
Qrx 6001-9001 the most advanced
Synth-decoders
The A and 5001 hybrid decoders
Qrx 2000-7500 early vario -matrix
Qr same as qs 1 early QS decoder

Own Qrx 7001 restored
Qrx 5001 restored
Qrx 3000 unrestored
And a Qs-1 unrestored
All flavours
Start rebuild of 3000 and Qs-1 soon
Do some comparisons
 
Just out of curiosity, has anyone compared the synthesized quad sound of the vintage receivers with modern multi-channel/surround sound receivers? The modern ones include several effects such as "music", "Hall", "Jazz", etc.
 
KeithD said:
Just out of curiosity, has anyone compared the synthesized quad sound of the vintage receivers with modern multi-channel/surround sound receivers?
Click to expand...
Based on my experience, the modern matrix processors (Dolby Pro-Logic, Dolby Pro-Logic II, dts Neo:6, Circle Surround) in general, produce much better synthesized multi-channel surround sound then the legacy decoders (QS, SQ, Stereo-4). The one exception may be the QS decoder in the QRX-x001 Sansui receivers. I have not heard the modern Logic 7 or Surround Master decoders, however; the reports on both are promising. The best case is when one has several decoders to choose from. Some modern receivers have as many as three decoder types built in. e.g. Kenwood VR-7070 has Dolby Pro-Logic II, neo:6 and Circle Surround II. There is no one best decoder for all music sources. One recording may sound better with Dolby Pro-Logic II and the next may sound better with Circle Surround and some recordings will sound best when played back in ordinary old-fashioned two channel stereo.

Another advantage of using a modern receiver is that it will be able to not only synthesize two-channel sources, it will be able to play high-quality discrete modern multi-channel sources (Dolby Digital, dts-CD, DVD-Audio, SACD, Blu-ray Pure Audio, etc.).

KeithD said:
The modern ones include several effects such as "music", "Hall", "Jazz", etc.
Click to expand...
Different manufacturers will have different implementations of these "effects". My limited experience is that, in general, the results are not good, however; I have found a few instances where one of these effects settings did improve the listening experience on a particular recording. Generally, I get better results with one of the modern matrix decoders.

Beyond which decoder or processor one uses, there are other considerations to keep in mind when optimizing synthesized multi-channel sound. The size of the room, speaker matching and speaker placement all will have a significant effect on the overall satisfaction when listening to multi-channel music.
 
KeithD said:
Just out of curiosity, has anyone compared the synthesized quad sound of the vintage receivers with modern multi-channel/surround sound receivers? The modern ones include several effects such as "music", "Hall", "Jazz", etc.
Click to expand...
I don't think that the modern multi-channel receivers sound as good as the synthesized quad output on my 4-channel Sanyo. But that's just my experience... others likely experience something different.
 
Thanks for all the helpful insights here. I was on the verge of purchasing a QRX-7500A. Re-read this thread and everyone's comments as well as comments on this page:

https://classicreceivers.com/sansui-qrx-7500

Seems like the 7500A will not give me better "virtual quad" sound than the QR-4500 I already have. Am I interpreting that right? If so, then the only real upgrade for me would be to get a QRX-x001 with the full "vario-matrix" IC.
 
The 7500a would be better much better
then the Qr , decoder and syth wise .
For the ultimate experience you need a Qrx 6001 up . The hybrid decoder is close,but not as defined because of its separation and lack of decoder chip.
On the right material the synthesizer is amazing, more bang for your buck then format quadraphonic.
 
Agreed!!
The 7500A has the Chip for the decoding but not the Control Chip, all you lose is a bit of separation....its way WAY better than the 4500, by far....its "almost" as good as the 7001-9001....
I would have pulled the trigger on the 7500A to be honest.....there aren't that many of them around and they often fly under the radar.
You could use it as a stepping stone to a QRX9001.
7500A amplifier circuits are really good, very nice amplifier.
Also has a great tuner..
 
OK, interesting. That website I listed makes it sound like the 7500A has the same "basic QS" decoder as the QR series of receivers, and so isn't any better at synthesized quad than the QR receivers are, but you guys are making a strong case that isn't true.

The 7500A isn't gone, I was just on the verge of buying it, but held off until I sought the advice on here. I'm still trying to get more pictures from the owner before committing.
 
KeithD said:
OK, interesting. That website I listed makes it sound like the 7500A has the same "basic QS" decoder as the QR series of receivers, and so isn't any better at synthesized quad than the QR receivers are, but you guys are making a strong case that isn't true.

The 7500A isn't gone, I was just on the verge of buying it, but held off until I sought the advice on here. I'm still trying to get more pictures from the owner before committing.
Click to expand...

The 7500A was what they called the Hybrid "in between" the 7500 and the 8001/9001...sort of thing..
There were two chips associated with the Vario Matrix, the Decoder and control Chips, the 7500A has the decoder chip, same as the 8001-9001, but it uses discrete circuit in place of the control chip at the cost of a bit of separation...
If the 7500A is a nice clean unit I'd get it.....I have done a big restoration on one, and I have another one sitting here waiting for parts.....I quite like working on them, quite modular in construction, as long as you don't have to get the VU meter drivers out!! That is not fun!!

Let us know how you go...
 
Here are a couple of pics. Guys is asking $600, which is what they seem to go for on e-bay in the U.S. Thoughts?

s-l1600 (1).jpgs-l1600.jpg
 
Looks nice, veneer looks passable, the wood is crying out for some oil though, they look really good with the furniture polish on the wood veneer.
The first thing I would do though, is buy a a bunch of Warm White LED fuse lamps, and replace all the function indicator lamps as well.
I can't remember how many bulbs in total, but if you download the manual they are all listed there in the parts list...
Email David, he'll help you out with the lamps. https://sites.google.com/site/dgwojocom/
I use him for all my restorations, very knowledgeable guy, and very helpful.
You will find some of the lamps aren't working, just the nature of things....But they look really nice when its all lit up properly. I use warm white simply because it looks quite close to the incandescent look which to me is 'right'...
Seems the going rate, maybe try and squeeze him down a bit, just because!!
 
For that money I'd go for a 6001 or a 7001
And get the full blown decoder
Hybrid has 1 HD 3103p and 1 HA 1327 Ic Phase control board, decoder board no ic s

6001 up have the ha 1328 decoder ic on one board and 2 HA 1327 and 1 hd3103 on the other board
Though the 7500a s a nice looking receiver
and the hybrid is pretty good
 
ig88 said:
For that money I'd go for a 6001 or a 7001
And get the full blown decoder
Hybrid has 1 HD 3103p and 1 HA 1327 Ic Phase control board, decoder board no ic s

6001 up have the ha 1328 decoder ic on one board and 2 HA 1327 and 1 hd3103 on the other board
Though the 7500a s a nice looking receiver
and the hybrid is pretty good
Click to expand...

Problem is finding one for that money...7001 is a bit rare I have noticed...

I think trying the 7500A isn't a bad move, and later on perhaps take the full plunge into a 9001 ....
 
Yes, price is a bit high, in my opinion. One listed on e-bay right now for $450 + $80 shipping.

Also see a 5500 listed for $350. Is the main difference between the 7500 and 5500 power output? I see the 7500a and 5500a have the same service manual. I don’t need high power. Cosmetically the 7500/5500 look identical. Also looks like same inputs.
 
Great thread.. alot of good info here.. I have been through the Pioneer family of quad receivers and I am working my way up the Sansuis. I am totally into vinyl, not a big fan of digital, at least for my primary set up in the man cave. I started with the Pioneer QX 8000, actually bought a second one as a spare. They were good receivers, but were sadly lacking in quad processing. Upgraded to a Pioneer QX9900 which is their TOTL quad receiver I could not pass on and this was noticeably better than the 8000. Found a Sansui QRX 5500a and was blown away at how much better the decoders were over the Pioneer. Not even in the same league. The 9900 was demoted to living room and the Sansui took its perch behind the bar. Loving the Sansui decoders and reading more about how the x001 series had the best decoders, I bought a QRX 6001 and sold the 5500a. Again, significant improvement in quad processing. Started having some issues with the CD4 demodulator and began looking into a full restoration and upgrade from QRXrestore.com to the tune of close to 1400 bucks which I was OK spending after always having some issue with every 40 year old receiver I ever bought. I happened to stumble onto a QRX8001 on ebay that had the full QRXrestore restoration and upgrade in 2015 which I was able to verify with them. I emailed them and they had the work order, customer name, serial number etc. It is in transit to my house and scheduled for a Black Friday delivery. I will soon be able to give a laymans review of the difference between a 6001 and a fully restored 8001.

I like that the x001 has SQ, QS and CD4 build it as I have many albums in each format. CD4 gets beat up alot but a few of my favorite Quad albums are in CD4. Allman Brothers; Live at the Fillmore East and Eat a Peach, Jethro Tull Aqualung and Black Sabbath Paranoid. These alone are worth a fully functional CD4 demodulator.
 
Finally got it all set up.. sounds amazing. the QS Synthesizer is awesome... crystal clear, warm sharp sounding. I do think I have an issue with my turntable playing CD 4. Symptoms are the same as my 6001, and I think its the handiwork of the previous owner. He replaced the RCA cable plugs and I think he at least put them on backwards. When I plug Red to right, White to left it does not detect the carrier signal, swap red to left, white to right and it detects it, but really poor and only comes in on one side. My 6001 did the same exact thing and I thought it was the receiver, now I think its the Turntable. Going to start by replacing the RCA cables completely and go from there.. Going to test with a friends turntable as well. Just odd that Red to right, White to left sounds terrific in stereo as well as SQ.

Turntable is a Technics SL 1800 MKII with Audio Technica TP112Sa cartridge w/ a ATN 12S Shibata stylus.
 

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patwalsh said:
Finally got it all set up.. sounds amazing. the QS Synthesizer is awesome... crystal clear, warm sharp sounding. I do think I have an issue with my turntable playing CD 4. Symptoms are the same as my 6001, and I think its the handiwork of the previous owner. He replaced the RCA cable plugs and I think he at least put them on backwards. When I plug Red to right, White to left it does not detect the carrier signal, swap red to left, white to right and it detects it, but really poor and only comes in on one side. My 6001 did the same exact thing and I thought it was the receiver, now I think its the Turntable. Going to start by replacing the RCA cables completely and go from there.. Going to test with a friends turntable as well. Just odd that Red to right, White to left sounds terrific in stereo as well as SQ.

Turntable is a Technics SL 1800 MKII with Audio Technica TP112Sa cartridge w/ a ATN 12S Shibata stylus.
Click to expand...
It is very important that the cables connecting between the record player and the inputs to the receiver are low capacitance. The total capacitance, including tonearm wiring, should be less than 100pF.
 
Thanks tcdriver,

I will get low capacitance cables when I replace them - does what I describe sound like it may be resolved by replacing the cables?
 
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