Quad question

KeithD

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I've had a Pioneer QX-949 playing well for a couple of months. However, it developed static in the rear channels, so it's now on my service bench. I recently picked up a QR-4500 to replace it temporarily in my quad system. However, I've been very surprised and impressed at how good this QR-4500 is. It's my first Sansui quad. It seems to have even better "simulated" quad (from 2 channel source) than the Pioneer QX-949 produces. However, the SQ decoding is not good. At this point I do have only one SQ record, so not a huge issue, but I'm wondering if the QRX-xx00 line is better? I've read a lot about how the QRX-x001 line is the best, but what about the QRX-xx00? Specifically, I'm keeping and eye out for a QRX-5500, 6500 or 7500. How do those compare to the QR series and the QRX-x001 series? Or can you point me to another thread or other source where this is explained?

Also, can anyone comment if Sansui Quads more "trouble-free" than Pioneer Quads? I've read something about Sansui not using caps on the amp boards, which leads to more reliable operation?

Thanks!
 
QRX7001 was TOTL before the 8001 and 9001 came out.
I've serviced a lot of QRX's, and the 7001 is the "sweet spot" for quad processing and reliability, it also has a very good tuner, whereas the 8001 and 9001 tuners are very average, they are also a pig to work on and the 9001 of course has the dreaded Dolby board which causes all sorts of intermittent problems.
But the 9001 would be the most powerful and best sounding amplifier out of all of them, the Quad processing is pretty much the same as the 7001...
You need to spend a lot of time/money making the 9001 reliable, whereas the 7001 just needs a squirt of deoxit, a recap, replace bias and offset trimmers and off you go.

They all have capacitors on the amp boards not sure where that rumour came form?

I liked the QRX7500A, I did a big restoration on one of those, and they are very well constructed and engineered, easy to work on, but they are a generation behind the 7001 series with the Quad processing...But the amplifier sounds great, and a good tuner as well.

But, at the age all of these units are, you need two spend some time and money getting them right, everything needs re-capping, I regularly find bad caps in the amplifiers I am working on these days, more than 10 years ago...
But once you have taken the time to go through it, you'll get a nice reliable unit.

Hope this helps, feel free to ask questions whilst all these QRX's are still fresh in my head......Which reminds me, I have a QRX9001 coming in for a major in a few weeks time...
 
Part of my interest in the QRX-x500 line is price part is aesthetics. They are less expensive than the x001 line (maybe the 7001 is an exception). They also have those cool VU meters and a nice wood case (is the 7001 case metal with simulated wood grain?)
 
I suppose the SQ decoding is "not good" on the QR-4500 because it's not ON the QR-4500 ... ;-}

Another vote for either the QRX-6001 or the QRX-7001 unless you're really into. Either has the TOTL quad decoders onboard, and both are easier to maintain and refurb than either the 8001 or 9001. Biggest difference is power output, and the big uns do have some additional features not available on their smaller brethren. I picked up on a 6001 to keep things going here while I restored the 9001, and truth be told, not that much difference as I use an outboard amp on the front channels. Good enough in fact, it allowed me to take my time on the 9001. Still got the 6001 as a spare ...

PS ... I spent a couple decades here listening to a QR-4500 and can't say I had any regrets. Very decent sound, and about the best IO available on ANY receiver ever. You can run a whole house on one with room to spare.

Oh ... and yes, the 6001 and 7001 are metal case.
 
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Yes, apparently the decoding on the QR series was SQ?

Agree on the QR-4500. It is a very impressive receiver. Had I purchased the 4500 first (rather than the Pioneer Qx-949), I would likely not have bought the Pioneer quad At all. However, it is good to have heard both for comparison.
 
Only true quad decoding on the QR series was Sansui's proprietary QS. Both that and SQ arrived at the same results using proprietary phase shifting to create the rear channels. End result was about the same as far as separation and rear channel dynamics, but the decoding processes were incompatible, resulting in some weirdness on playback.

Kinda like VHS and BetaMax ... the same, only different?

Also good time to mention that each succeeding version of the decoders improved separation, especially front to rear.. Different series also had different synthesized surround as well. I much preferred the results on the QR4500 compared to either of my QRX receivers, and the best I found was with a QR 800. Once again, different strokes for different folks.

Popular opinion is that either QS or SQ can be used with standard stereo to create distinct rear channels, and that QS does a better job of it. In my case, I much prefer what SQ does with stereo, but to each their own. Truth be told, I run ALL my music in SQ except that which I know was encoded using another process. Can't really remember when's the last time I listened to two channel stereo without adding the rear channels.

PS ... all the QRX series added CD4 to the options, but I found that was more BS than it was worth. It also requires special playback equipment (low capacitance turntable and a shibata tip cartridge). I found keeping the system aligned properly wasn't really worth the effort, and it's not like you can find much CD4 nowadays anyway.

Oh. You'd be surprised how much "stereo" was actually quad encoded. Stuff played back fine on stereo equipment, and saved the labels having to make and stock multiple versions of the same titles.
 
Hahaha, nice one Skizo, you beat me to it!! I was about to say pretty much the same thing...

SQ was the Sony system wasn't it?

However I have found that Sansui did a really nice job of all the different decoders whereas some of the other manufactures didn't...
 
Part of my interest in the QRX-x500 line is price part is aesthetics. They are less expensive than the x001 line (maybe the 7001 is an exception). They also have those cool VU meters and a nice wood case (is the 7001 case metal with simulated wood grain?)
Yes the QRX7500A was the TOTL before the X001 series came along, the decoding is reasonably good, but most importantly the units are very well constructed, and the amplifier circuitry is very very good, after I recapped, replaced some of the noisy old small signal transistors, and fitted some Nichicon Gold Tunes for the main caps, it was a bit of a stunner sound wise, I really liked it.
The A has a better designed Vario Matrix than the Non A version. The A has much better separation.
 
Hahaha, nice one Skizo, you beat me to it!! I was about to say pretty much the same thing...

SQ was the Sony system wasn't it?

However I have found that Sansui did a really nice job of all the different decoders whereas some of the other manufactures didn't...
I believe SQ was Columbia/CBS from what I've read.

Also good time to mention that each succeeding version of the decoders improved separation, especially front to rear.. Different series also had different synthesized surround as well. I much preferred the results on the QR4500 compared to either of my QRX receivers, and the best I found was with a QR 800. Once again, different strokes for different folks.

Popular opinion is that either QS or SQ can be used with standard stereo to create distinct rear channels, and that QS does a better job of it. In my case, I much prefer what SQ does with stereo, but to each their own. Truth be told, I run ALL my music in SQ except that which I know was encoded using another process. Can't really remember when's the last time I listened to two channel stereo without adding the rear channels.
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.
 
Not what I said ...

(read read read)

Yup. Nope ... <G>

What I believe I said was the QR synthesized quad (SURROUND) outperforms that of the QRX synthesized quad (SURROUND). Both QS and SQ outperform any of the synthesized modes as you'd expect, giving you more consistent results, as they're four distinct channels mapped out during mastering. I've collected quite a few SQ and QS encoded vinyls over time and will always switch to those modes when playing back those titles.

(And yes, I said vinyls, so shoot me already) ;-}

Also, any of the modes (except for CD4 and direct connect) will work with stereo material. As mentioned earlier, I really like what SQ does with straight stereo and will normally use that. If I don't like what I'm hearing, or think it could be better, I'll look up the title in "The Quadraphonic Bible" and invariably find it was encoded in QS, and they just didn't bother telling us on the jacket.

PS ... one exception to my rule ... I usually will fire up HALL mode for stereo orchestral material. Adds a nice presence and ambiance as well as widening the front stage, and it's not like you want instruments flying at you from the back of the room anyway while listening to that sort of thing.
 
What I believe I said was the QR synthesized quad (SURROUND) outperforms that of the QRX synthesized quad (SURROUND).
Yes, that's what I understood. My question is, why?

Since I am much more interested in the synthesized quad performance than decoding quad performance, I want to have the best receiver for synthesized quad. So, just curious what makes the QR line better a synthesized quad than the QRX models?

Thanks, hope there's no misunderstanding here of what I'm asking. :)
 
Understood ...

Truth be told, I never got into the science behind that ... I just know what I like. Maybe the analog vs digital thing? I suppose a lot would depend on your listening area and equipment, not to mention ears as well as musical tastes and personal preference. As with all things audio, lot of things factor in, there's no definitive answer, leaving it up to YOU to decide what you prefer ... and there's really only one way to find that out.

(I suppose getting one of each is out of the question?) <G>
 
I believe SQ was Columbia/CBS from what I've read.
and Sony, just looked it up....was a collaboration.

I have found in my journey servicing a lot of quad gear that Sansui has the best performing decoders and synthesisers, their CD4 is even better than the JVC, and they were the ones who developed it.

Your choice of the QRX7500 is a good one, and certainly the QRX7001 will outperform it, so there's your choices.
Make sure the QRX7500 if you get one is a 7500A with the improved vario matrix.
 
Yes, that's what I understood. My question is, why?

Since I am much more interested in the synthesized quad performance than decoding quad performance, I want to have the best receiver for synthesized quad. So, just curious what makes the QR line better a synthesized quad than the QRX models?

Thanks, hope there's no misunderstanding here of what I'm asking. :)

Argh, missed this post, if you want synthesised performance, then get the QRX7001, it is better than the 7500A.......its the vario matrix that synthesises the surround, and the 7001 has the best...unless you want to go full Hog and get the QRX8001 or 9001...
 
Here's a QRX777 I was servicing next to the AU9500 which is essentially a 7001, the 777 has a blue tuner dial and meters and the upper part is black whereas the 7001 has green tuner dial and meters and silver tp, also has a different IF tuner board, which is neither here nor there...
But they are an elegant looking unit, they just don't have the output or VU meters. In the other picture you can see the 7001 next to the AU-X1 and the 777 and the 7500A sitting further off to the right....just to give you an idea of the relative looks, the 7500 is a much bigger unit too, wider and taller.
IMG_5850.JPG IMG_5882.JPG
 
and Sony, just looked it up....was a collaboration.

I have found in my journey servicing a lot of quad gear that Sansui has the best performing decoders and synthesisers, their CD4 is even better than the JVC, and they were the ones who developed it.

Your choice of the QRX7500 is a good one, and certainly the QRX7001 will outperform it, so there's your choices.
Make sure the QRX7500 if you get one is a 7500A with the improved vario matrix.

You're making me doubt myself. I have a 7001 and also a Marantz 4270 with both the SQA-2b and the CD-400 decoder. I was thinking once the 4270 was fixed I'd sell the 7001 as the former has pre outs. Bad idea? I *could* replace the 2000A in the kitchen with the 7001 and sell the 2000A instead, but a) I really like the 2000A and b) I'd have to somehow justify taking up even more kitchen shelf space just to listen to NPR while I'm frying up breakfast...
 
Thanks for all those pictures kevzep. Somehow the looks of the 7001 just don't do it for me. I really like the looks of the 7500, 8001, 9001, but the latter two are way too expensive for me at $1k+. The 7500 is more reasonable in the $300-$400 range.

Sansui's quad series is a bit confusing to me. Some of the QRX-x500 models kept the same styling as the QR-4500/6500, while the 7500 is in line with the 8001 and 9001, but the 7001 and 6001 have their own style. Would have been easier if the styling matched the model number line, but oh well.

I don't have much motivation to spend a lot of $$ to get another quad receiver. I'm enjoying the QR-4500, and I'll eventually finish the restoration of the two Pioneer QX-949s I have. So... don't really need another quad unit, hence my main motivation is to get something better in both looks and performance if I go ahead and spend the money. However, can't spend $1k on the two at the top. I'm thinking the 7500 may be the best compromise for price/performance/looks. To go to the 8001, I have to spend over twice as much, but would I get twice as much performance given that I mainly want simulated quad? The aesthetics are essentially the same between the 7500 and 8001/9001.
 
Do you have a Sansui t-shirt/sweat to go with that collection? :)
Somehow they just come to me like some kind of migration......its like they somehow know and the emails, phone calls, keep on coming, all of those in the pic are just in for repair...
But you're right, I need a Sansui T-Shirt/Sweat shirt....!!

Thanks for all those pictures kevzep. Somehow the looks of the 7001 just don't do it for me. I really like the looks of the 7500, 8001, 9001, but the latter two are way too expensive for me at $1k+. The 7500 is more reasonable in the $300-$400 range.

Sansui's quad series is a bit confusing to me. Some of the QRX-x500 models kept the same styling as the QR-4500/6500, while the 7500 is in line with the 8001 and 9001, but the 7001 and 6001 have their own style. Would have been easier if the styling matched the model number line, but oh well.

I don't have much motivation to spend a lot of $$ to get another quad receiver. I'm enjoying the QR-4500, and I'll eventually finish the restoration of the two Pioneer QX-949s I have. So... don't really need another quad unit, hence my main motivation is to get something better in both looks and performance if I go ahead and spend the money. However, can't spend $1k on the two at the top. I'm thinking the 7500 may be the best compromise for price/performance/looks. To go to the 8001, I have to spend over twice as much, but would I get twice as much performance given that I mainly want simulated quad? The aesthetics are essentially the same between the 7500 and 8001/9001.

Honestly, you can't go wrong with the 7500A, but make sure its the A variant....I like the looks of the 7500 as well, and I, at some point may end up with one of those, they are good buying and they are great performers..
 
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