QRX-9001 + Fosgate Tate II (or alternative)

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QuantumGuitar

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Hey so I've got a QRX-9001, the CD-4 and QS work great, but id say the SQ leaves something to be desired. I'm dreaming of a Fosgate Tate II 101A, though I'm open to other suggestions. Basically I'm looking for any suggestions on incorporating an external SQ decoder into my current system. I'm using the QRX-9001 as my phono-preamp and decoder, which I'm then sending through the quad tape-out (Tape-2 4ch rec) to another receiver. Maybe running the stereo Tape-1 stereo rec into the external SQ and then into the Tape-2 4ch Play? Anyone have any experience? My 9001 is currently in the shop, and I haven't purchased an extra decoder yet, though I'd like to look into functionality before dropping some serious $$$ on a Tate II or otherwise.

Thanks.
 

Quadzilla

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I have a QRX-7001, and I can tell you that there are VERY few stand-alone SQ decoders that are better than the Sansui's. Besides the Tate units and the Surround Master, the only ones that come to mind are the Lafayette SQ-W and the Sony SQD-2020 or the (better) 2010. The Pioneers are the worst, and I wouldn't bother with a lesser Sony either. Other brands are pretty dismal too.

I have told you before (and you didn't want to hear it then), but using a modern stand-alone phono preamp will improve matrix decoding MUCH more than you might think. I realize that makes using the Sansui's CD-4 demodulator more difficult, but I use a stand-alone JVC demodulator anyway ... then run the phono signal to a Rega Fono preamp.
 

QuantumGuitar

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I have a QRX-7001, and I can tell you that there are VERY few stand-alone SQ decoders that are better than the Sansui's. Besides the Tate units and the Surround Master, the only ones that come to mind are the Lafayette SQ-W and the Sony SQD-2020 or the (better) 2010. The Pioneers are the worst, and I wouldn't bother with a lesser Sony either. Other brands are pretty dismal too.

I have told you before (and you didn't want to hear it then), but using a modern stand-alone phono preamp will improve matrix decoding MUCH more than you might think. I realize that makes using the Sansui's CD-4 demodulator more difficult, but I use a stand-alone JVC demodulator anyway ... then run the phono signal to a Rega Fono preamp.
Ah, I know you have. And I appreciate your continued input and emphasis. I still just can't/don't have quite the space for a separate CD-4 and matrix turntable setup. I also can't stand having to unplug and re-plug things in order to play different formats...but I really should give the SQ an a/b with a newer phono-pre. Maybe if the results are good enough it would motivate me to buy a new dedicated phono-pre (I'd have to borrow one from another room's setup for the a/b) and save some $$$ from not buying another decoder...
...Thanks again
 

QuantumGuitar

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I contacted Jim at QRX Restore who believes that the 2 ch tape loop, through an external decoder, back into the 4ch tape loop, out the 4ch rec method should work for the 9001. I'll have to confirm if I ever get a chance though.
 
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ss9001

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^^ That's the way I have used my 9001 with an Audionics S&IC (w/ Tate II chips so = Fosgate-Tate) decoder and various NR & dynamic range expansion gear. The 2 ch tape out is pure 2 channel into the SQ decoder. My 9001 has been modded to have preamp outs & blend resistors removed. So I don't have to use 4 ch rec outs but should work just fine.

The Audionics & Fosgate units audibly outperform Sansui's SQ function, much improving front/back channel separation. And the synthesis is close to Sansui's but IMO not quite the equal. So worth trying to have both.

So stick with the 9001 and try to add a Fosgate/Audionics. You will not be disappointed with its SQ vs Sansui's. 25-40 dB separation beats Sansui's 12 and it is audible ;) There were 2 Audionics composers on Ebay not long ago that the seller was selling as-is that he said need repair. I don't know if they are still listed or if Jim is willing to tackle a Tate/Audionics.

I recently added a Jim restored-repaired QSD-1 which is also connected in the 9001's tape loop. I am the original owner of the 9001 bought new in '78 or 79 and had restored with the blend resistors removed, calibrated and preamp outs installed. But Jim's suggestion to use the 4 ch rec outs should work just fine.

I can also share my experiences with the Involve surroundmaster if you are interested but off topic to your thread so PM if you want :)

Hope this helps!
 
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surround.sound.enthusiast

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I support the prior suggestion of Lafayette SQ-W if you're not able to afford a Fosgate/Tate or Audionics Space and Image Composer when they come up for sale. The SQ-W's do a damn good job.
As also mentioned, Involve Audio's Surround Master has rave reviews - I don't have one yet myself, I've ended up holding out for the new model when it gets released.
 

QuantumGuitar

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So I'm back to this old problem again...

Reviewing the QRX-9001 manual I see the internal SQ decoder is rated for 12dB back to front and 20dB between front channels (Maybe I'll arbitrarily call that 16dB and 25dB with the blend resistors removed, but based on what??). Comparing that to the QS rating of 20dB between adjacent channels and 30dB between diagonal (lets call that 25dB and 35dB, why not??) I can see why I've preferred the QS in the unit.
Looking at the Fosgate Tate II manual I see a claim of 35dB-50dB separation depending on direction, and you know I take quantifiable performance ratings with a grain of salt, but it does give me hope that some audible improvement is really possible and not just in a diminishing returns hi-fi audio world sort of way.
I finally recently reviewed the signal path possibilities in the 9001, and found that a loop through the 2-ch tape-1 rec -> decoder -> 4-ch tape-2 play would make the perfect external decoder setup since the 4-ch tape-2 play inputs can't be decoded internally in my current setup using the 4-ch tape-2 rec outputs. So now I'm actually a bit motivated to make this improvement.
I just put a rather low offer in on Ebay for a Tate II that needs a bit of tlc (no channels out just a hum, so hopefully the ICs should be fine and my poor 9001 tech should probably be able to handle anything else), but have also had my interested piqued by the surround master. I might consider one once the v3 is officially announced?
So, I'm also wondering how the QRX-9001's vario-matrix QS decoder might compare to both the QSD-1 and the Involve Surround Master, though I've found the QRX decoder to be adequate enough for the handful of QS recordings I own. (looks like the QSD-1 manual rates adjacent and diagonal separation the same as the QRX manual, does the QSD-1 have blend resistors than can also be removed or am I missing something?...further research looks like it does...)
Regarding the Surround Master, the only thing that's keeping it from being the #1 ideal candidate for me is that I think I've heard its a software decoder, is that correct? And I don't know, I'm trying to keep my analog side of things intact. I know I almost definitely wouldn't be able to tell the difference and it would probably be cleaner and more efficient with its decoding and lack of necessary maintenance, but its still something I think I would rather avoid if possible.
So anyway, my real priority is just upgrading the SQ decoder, and since I will continue to use the 9001 for cd-4 playback and 2 channel surround synthesizer functionality, it seems like my best two options are:
1. Fosgate Tate II 101A: for improved SQ without digital conversions (right?)
2. Involve Surround Master v3: for improved SQ with digital conversions, with the added bonus of a non-essential (I say this now) QS upgrade.

If I can get this/a Tate II for like $300 + repairs, basically less than the involve SM, I think I might go that route. But if it'll save me money, the surround master seems like its probably the smarter move for both the SQ and QS upgrades, since I already have a quad synthesizer? Idk.
Any thoughts?

Edit: I just went through all of the QS labeled here (Quadraphonic Discography "Popular Recordings - Complete List") and even-though I have a handful of them, I really don't care about any of them...so that drops a minor QS improvement to almost negligible importance...
 
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furui_suterioo

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So I'm back to this old problem again...

Reviewing the QRX-9001 manual I see the internal SQ decoder is rated for 12dB back to front and 20dB between front channels (Maybe I'll arbitrarily call that 16dB and 25dB with the blend resistors removed, but based on what??). Comparing that to the QS rating of 20dB between adjacent channels and 30dB between diagonal (lets call that 25dB and 35dB, why not??) I can see why I've preferred the QS in the unit.
Looking at the Fosgate Tate II manual I see a claim of 35dB-50dB separation depending on direction, and you know I take quantifiable performance ratings with a grain of salt, but it does give me hope that some audible improvement is really possible and not just in a diminishing returns hi-fi audio world sort of way.
I finally recently reviewed the signal path possibilities in the 9001, and found that a loop through the 2-ch tape-1 rec -> decoder -> 4-ch tape-2 play would make the perfect external decoder setup since the 4-ch tape-2 play inputs can't be decoded internally in my current setup using the 4-ch tape-2 rec outputs. So now I'm actually a bit motivated to make this improvement.
I just put a rather low offer in on Ebay for a Tate II that needs a bit of tlc (no channels out just a hum, so hopefully the ICs should be fine and my poor 9001 tech should probably be able to handle anything else), but have also had my interested piqued by the surround master. I might consider one once the v3 is officially announced?
So, I'm also wondering how the QRX-9001's vario-matrix QS decoder might compare to both the QSD-1 and the Involve Surround Master, though I've found the QRX decoder to be adequate enough for the handful of QS recordings I own. (looks like the QSD-1 manual rates adjacent and diagonal separation the same as the QRX manual, does the QSD-1 have blend resistors than can also be removed or am I missing something?...further research looks like it does...)
Regarding the Surround Master, the only thing that's keeping it from being the #1 ideal candidate for me is that I think I've heard its a software decoder, is that correct? And I don't know, I'm trying to keep my analog side of things intact. I know I almost definitely wouldn't be able to tell the difference and it would probably be cleaner and more efficient with its decoding and lack of necessary maintenance, but its still something I think I would rather avoid if possible.
So anyway, my real priority is just upgrading the SQ decoder, and since I will continue to use the 9001 for cd-4 playback and 2 channel surround synthesizer functionality, it seems like my best two options are:
1. Fosgate Tate II 101A: for improved SQ without digital conversions (right?)
2. Involve Surround Master v3: for improved SQ with digital conversions, with the added bonus of a non-essential (I say this now) QS upgrade.

If I can get this/a Tate II for like $300 + repairs, basically less than the involve SM, I think I might go that route. But if it'll save me money, the surround master seems like its probably the smarter move for both the SQ and QS upgrades, since I already have a quad synthesizer? Idk.
Any thoughts?
Does your 9001 have the blend resistors removed? Just wondering. I see that Tate 101a on the bay is in need of some maintenance, it seems like many of them are these days(mine included), I hope they can still be fixed eventually, even with the availability of the SM(which is definitely a worthy successor).
 

QuantumGuitar

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Does your 9001 have the blend resistors removed? Just wondering. I see that Tate 101a on the bay is in need of some maintenance, it seems like many of them are these days(mine included), I hope they can still be fixed eventually, even with the availability of the SM(which is definitely a worthy successor).
I did have the blend resistors removed and a holy grail alignment performed, which definitely helped a lot, but the SQ decoding just isn't cutting it for me, so I'm hoping to try an external decoder with the qrx. I've got a guy that has worked wonders for my 9001 for cheap, so I imagine he should ideally be able to take care of it. I actually just picked it back up from him recently after a faulty transistor in the decoder circuitry was on the fritz.
 

Sonik Wiz

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So I'm back to this old problem again...

Reviewing the QRX-9001 manual I see the internal SQ decoder is rated for 12dB back to front and 20dB between front channels (Maybe I'll arbitrarily call that 16dB and 25dB with the blend resistors removed, but based on what??). Comparing that to the QS rating of 20dB between adjacent channels and 30dB between diagonal (lets call that 25dB and 35dB, why not??) I can see why I've preferred the QS in the unit.
Looking at the Fosgate Tate II manual I see a claim of 35dB-50dB separation depending on direction, and you know I take quantifiable performance ratings with a grain of salt, but it does give me hope that some audible improvement is really possible and not just in a diminishing returns hi-fi audio world sort of way.
I finally recently reviewed the signal path possibilities in the 9001, and found that a loop through the 2-ch tape-1 rec -> decoder -> 4-ch tape-2 play would make the perfect external decoder setup since the 4-ch tape-2 play inputs can't be decoded internally in my current setup using the 4-ch tape-2 rec outputs. So now I'm actually a bit motivated to make this improvement.
I just put a rather low offer in on Ebay for a Tate II that needs a bit of tlc (no channels out just a hum, so hopefully the ICs should be fine and my poor 9001 tech should probably be able to handle anything else), but have also had my interested piqued by the surround master. I might consider one once the v3 is officially announced?
So, I'm also wondering how the QRX-9001's vario-matrix QS decoder might compare to both the QSD-1 and the Involve Surround Master, though I've found the QRX decoder to be adequate enough for the handful of QS recordings I own. (looks like the QSD-1 manual rates adjacent and diagonal separation the same as the QRX manual, does the QSD-1 have blend resistors than can also be removed or am I missing something?...further research looks like it does...)
Regarding the Surround Master, the only thing that's keeping it from being the #1 ideal candidate for me is that I think I've heard its a software decoder, is that correct? And I don't know, I'm trying to keep my analog side of things intact. I know I almost definitely wouldn't be able to tell the difference and it would probably be cleaner and more efficient with its decoding and lack of necessary maintenance, but its still something I think I would rather avoid if possible.
So anyway, my real priority is just upgrading the SQ decoder, and since I will continue to use the 9001 for cd-4 playback and 2 channel surround synthesizer functionality, it seems like my best two options are:
1. Fosgate Tate II 101A: for improved SQ without digital conversions (right?)
2. Involve Surround Master v3: for improved SQ with digital conversions, with the added bonus of a non-essential (I say this now) QS upgrade.

If I can get this/a Tate II for like $300 + repairs, basically less than the involve SM, I think I might go that route. But if it'll save me money, the surround master seems like its probably the smarter move for both the SQ and QS upgrades, since I already have a quad synthesizer? Idk.
Any thoughts?

Edit: I just went through all of the QS labeled here (Quadraphonic Discography "Popular Recordings - Complete List") and even-though I have a handful of them, I really don't care about any of them...so that drops a minor QS improvement to almost negligible importance...
I have never owned a Sansui receiver but I have owned & listened extensively to Sansui QSD-1 /D2, built a two band Vario-Matrix decoder, and owned a Fosgate Tate II, currently using an Involve Audio SM v2 as main decoder. They all have their good points & compromises. In olden dyas the Fosgate/Tate or Audionics S & IC was the go to units for top SQ decoding, because there was nothing else available back then except Sansui QS that wasn't quite as good as the other two units. Now of course today we have the Surround Master which is a reliable excellent performer & alternative choice to the classic units. For QS decoding it is the highest seperation, cleanest artifact free unit I've ever heard. The center front to center back leakage is a bit higher in SQ than QS mode but that trade off is minimal compared to the gains over legacy gear. The only drawback that is important to me is the lack of a 270 deg stereo synth mode on the SM. All the older units mentioned above had that.

In another post I detailed the sep specs of the SM v2 for both QS & SQ. In most all respects the seperation exceeds what could be accomplished in the old days. Have a look here if you want:


$350 for a knowingly broken Fosgate Tate II seems pretty risky to me. I wouldn't count on it being so easy to repair. There is poor documentation for servicing procedures & the circuitry is not at all like a Vario-Matrix decoder, more complex to fine tune. Also the Tate chips are unobtainable where as Sansui VM chips can still be had.

Edit:
Regarding the Surround Master, the only thing that's keeping it from being the #1 ideal candidate for me is that I think I've heard its a software decoder, is that correct? And I don't know, I'm trying to keep my analog side of things intact.
It is a hybrid unit. As Chucky would say all the maths is done digitally. That is direction sensing, control voltages, etc. The actual signal that you listen to is pure analog.
 
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par4ken

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So I'm back to this old problem again...

Reviewing the QRX-9001 manual I see the internal SQ decoder is rated for 12dB back to front and 20dB between front channels (Maybe I'll arbitrarily call that 16dB and 25dB with the blend resistors removed, but based on what??). Comparing that to the QS rating of 20dB between adjacent channels and 30dB between diagonal (lets call that 25dB and 35dB, why not??) I can see why I've preferred the QS in the unit.
Looking at the Fosgate Tate II manual I see a claim of 35dB-50dB separation depending on direction, and you know I take quantifiable performance ratings with a grain of salt, but it does give me hope that some audible improvement is really possible and not just in a diminishing returns hi-fi audio world sort of way.
I finally recently reviewed the signal path possibilities in the 9001, and found that a loop through the 2-ch tape-1 rec -> decoder -> 4-ch tape-2 play would make the perfect external decoder setup since the 4-ch tape-2 play inputs can't be decoded internally in my current setup using the 4-ch tape-2 rec outputs. So now I'm actually a bit motivated to make this improvement.
I just put a rather low offer in on Ebay for a Tate II that needs a bit of tlc (no channels out just a hum, so hopefully the ICs should be fine and my poor 9001 tech should probably be able to handle anything else), but have also had my interested piqued by the surround master. I might consider one once the v3 is officially announced?
So, I'm also wondering how the QRX-9001's vario-matrix QS decoder might compare to both the QSD-1 and the Involve Surround Master, though I've found the QRX decoder to be adequate enough for the handful of QS recordings I own. (looks like the QSD-1 manual rates adjacent and diagonal separation the same as the QRX manual, does the QSD-1 have blend resistors than can also be removed or am I missing something?...further research looks like it does...)
Regarding the Surround Master, the only thing that's keeping it from being the #1 ideal candidate for me is that I think I've heard its a software decoder, is that correct? And I don't know, I'm trying to keep my analog side of things intact. I know I almost definitely wouldn't be able to tell the difference and it would probably be cleaner and more efficient with its decoding and lack of necessary maintenance, but its still something I think I would rather avoid if possible.
So anyway, my real priority is just upgrading the SQ decoder, and since I will continue to use the 9001 for cd-4 playback and 2 channel surround synthesizer functionality, it seems like my best two options are:
1. Fosgate Tate II 101A: for improved SQ without digital conversions (right?)
2. Involve Surround Master v3: for improved SQ with digital conversions, with the added bonus of a non-essential (I say this now) QS upgrade.

If I can get this/a Tate II for like $300 + repairs, basically less than the involve SM, I think I might go that route. But if it'll save me money, the surround master seems like its probably the smarter move for both the SQ and QS upgrades, since I already have a quad synthesizer? Idk.
Any thoughts?

Edit: I just went through all of the QS labeled here (Quadraphonic Discography "Popular Recordings - Complete List") and even-though I have a handful of them, I really don't care about any of them...so that drops a minor QS improvement to almost negligible importance...
Sansui refers to their SQ decoding as "Half Logic" and while it's not bad it's not exceptional either. I've had the S&IC since the very early eighties, my original unit was acting up (bad DES chip) but I recently found another one (original Tate chips, my original unit has the Tate II chips). I still think that it is the best way to decode SQ. I have the SQ Involve (evaluation module) and it does work well, but I prefer the imaging and sound quality of the S&IC, even with the old chips. Chucky said something about phase shifting being done in the analog domain in the Surround Master, so the unit could be a hybrid as Sonik said. I do believe that most of the Involve processing is done via DSP, otherwise the decoder would not be able to "look ahead" and would have much lower specs.
 
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Sonik Wiz

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Sansui refers to their SQ decoding as "Half Logic" and while it's not bad it's not exceptional either. I've has the S&IC since the very early eighties, my original unit was acting up (bad DES chip) but I recently found another one (original Tate chips, my original unit has the Tate II chips). I still think that it is the best way to decode SQ. I have the SQ Involve (evaluation module) and it does work well, but I prefer the imaging and sound quality of the S&IC, even with the old chips. Chucky said something about phase shifting being done in the analog domain in the Surround Master, so the unit could be a hybrid as Sonik said. I do believe that most of the Involve processing is done via DSP, otherwise the decoder would not be able to "look ahead" and would have much lower specs.
You've got me curious Ken. Have you ever had a chance to compare the Audionics S&IC to a Fosgate Tate II? SQ decoding and stereo surround?
 

par4ken

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You've got me curious Ken. Have you ever had a chance to compare the Audionics S&IC to a Fosgate Tate II? SQ decoding and stereo surround?
No I haven't but suspect that they should sound very similar. I do think that Audionics put more care into the analog circuitry though. Running the op-amps in class A, the soft clip circuit and the eight pole all-pass filters. Also the adjustable stereo enhance circuit and the separation control.

From what I recall reading was that the Fosgate units having a differently (from Audionics) designed interface circuit, operated faster and had a bit higher separation than the S&IC.
 

gvl_guy

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So all this is pretty much over my head, but I'm trying to learn. In any case, I recently bought a 9001 from the QRX Restore. They did the holy grail alignment. What are these blend resistors you mention? How do I know if they've been removed? And what exactly do they do?

I'm very happy with the QS and synthesize modes. But more of my albums (obviously) are SQ. So I'm hoping to beef that up. (I'm kinda thinking about the Surround Master, but not sure if it's worth the investment. I only have this vintage stuff and an Oppo plugged into the 9001 for modern discs )

Thanks for your help and patience. 🙂
 

Sonik Wiz

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So all this is pretty much over my head, but I'm trying to learn. In any case, I recently bought a 9001 from the QRX Restore. They did the holy grail alignment. What are these blend resistors you mention? How do I know if they've been removed? And what exactly do they do?

I'm very happy with the QS and synthesize modes. But more of my albums (obviously) are SQ. So I'm hoping to beef that up. (I'm kinda thinking about the Surround Master, but not sure if it's worth the investment. I only have this vintage stuff and an Oppo plugged into the 9001 for modern discs )

Thanks for your help and patience. 🙂
Usually this is referring to blend circuit at the final output of the decoder. It is in all Sansui VM circuits. It consists of a resistor/capacitor circuit between front L/R & rear L/R. The basic effect is to decrease L/R separation at lower frequencies & increase it towards the higher frequencies. With no clear statement from Sansui I think they did this to stabilize the output. In those days the wild card combination of LP's, TT & carts, cassette decks & don't forget FM allowed for wide swings of quality input. I think Sansui gave up a little bit in sep specs to get a more stable decoded output.

In the circuit there is one resistor that controls the amount of blend & this is the one that's clipped. It gives maximum separation that most of us prefer.

Tough call on the Surround Master since it's redundant with the QRX. And also the SM doesn't have Hall or Synthesizer. On the other hand it is superior SQ decoding compared to the Sansui. :unsure:

Edit: How do you know if they've been removed during Holy Grail tune up? Ask. Otherwise your opening evrything with a service manula to locate the resistors & see if they are there or not.
 
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