Smell of Smoke

[The Quadfather]

I will order the Involve SQ if I can ever get the discount code to work. I read that it is pretty much equivalent to the Audionics in performance, Quaddies who have bought one really like it. With the discount code, the Involve SQ V2 is half the price of the Audionics if you don't count inflation which has been substantial since 1978. So, the price is right. I think I'll just call them and order it over the phone. If you still prefer the Tate, I'd say let's put the two together and see if we can get a good one out of it, but then there would be this bloody fight over who gets to keep it. So, I will hang on to it, hoping someday I will have some way to ressurect it. It's been a good one, it served me since 1978, I will miss it. Audionics Space and Image Composer, serial 12132, R.I.P.

 

[Sonik Wiz]

The Audionics is a beautiful piece of audio history & I've always admired it. I don't have one, always wanted one. My expectation would be the biggest difference between them would be the surround from stereo synthesis. I have the Tate 101A & it provides a true 270 deg wrap around effect by intention & on the SM v2 it can do it but in a different way; if the right phase/amplitude happens to be in the stereo material.

I will say that I have no regrets getting the SMv2. It is so clear, distinct, no artifacts. And with a little bit of pre-synth also does a great job of wrap around sound. And the SQ decoding is so clean I would never go back to my Tate.

Others opinions may certainly differ & I respect that.

 

[DuncanS]

I will order the Involve SQ if I can ever get the discount code to work. I read that it is pretty much equivalent to the Audionics in performance, Quaddies who have bought one really like it. With the discount code, the Involve SQ V2 is half the price of the Audionics if you don't count inflation which has been substantial since 1978. So, the price is right. I think I'll just call them and order it over the phone. If you still prefer the Tate, I'd say let's put the two together and see if we can get a good one out of it, but then there would be this bloody fight over who gets to keep it. So, I will hang on to it, hoping someday I will have some way to ressurect it. It's been a good one, it served me since 1978, I will miss it. Audionics Space and Image Composer, serial 12132, R.I.P.

You won't regret it, excellent piece of kit

 

[jaybird100]

My S&IC worked quite nicely for several years, then I noticed a "sputtering" sound in one channel that sounded like a capacitor breaking down. I'd love to fix it, but I'm not handy at that sort of thing. No one in South Florida seems to want to undertake a recapping job. Guess I'll keep trying. I only wish Audionics would have included some form of RM decoding, but I guess the SQ folks put the kibosh on that.

 

[par4ken]

My S&IC worked quite nicely for several years, then I noticed a "sputtering" sound in one channel that sounded like a capacitor breaking down. I'd love to fix it, but I'm not handy at that sort of thing. No one in South Florida seems to want to undertake a recapping job. Guess I'll keep trying. I only wish Audionics would have included some form of RM decoding, but I guess the SQ folks put the kibosh on that.

Any decent electronic service man should be able to replace some capacitors. The S&IC is very easy to work on in that regard. Would a capacitor cause a sputtering sound though, I don't know. The SQ system and RM/QS are rather two different animals, it would of been difficult and expensive to add that feature I suspect. By the time the S&IC came out quad was dying so the main use of the unit was Stereo enhancement. Enhancement via SQ can be very effective, I normally ran it with the control fully clockwise, left came from left rear, right from right rear, center up front. You don't get a lot of left and right front output this way though, for that to happen the stereo signal would need 90° phase shifted components and that just doesn't happen naturally. I have been using the Photolume decoder (QSD-2 clone) for stereo enhancement lately and an blown away by the results in surround mode, as often each speaker position is filled.
I have a QSD-1 on another system and it in fact it sounds a bit more active (then Photolume) but I believe that the triple banding colours the sound. Triple banding is in part meant to reduce artifacting, but I hear no artifacts with vario-matrix decoding. DES can produce artifacts but that is usually only noticeable in rear channels, and then mainly noticeable when listened to in isolation. Audionics put in a separation control so that you could dial down the separation if artifacting became a problem. I don't think that I ever used it.
I have the Involve and Involve SQ evaluation modules. I don't like stereo played though straight QS mode, IMHO it needs a bit of pre-synth (QS surround mode). I really haven't done a lot of listening to the Involve SQ yet, with all the discrete DV SACD's that came out there is less and less need to decode SQ.

 

[Sonik Wiz]

I have a QSD-1 on another system and it in fact it sounds a bit more active (then Photolume) but I believe that the triple banding colours the sound. Triple banding is in part meant to reduce artifacting, but I hear no artifacts with vario-matrix decoding.

At one time I had a 2 band Photolume decoder, a QSD-1 & a QSD-2. I can't say as I remember the Photolume being more active than the other two. I do recall my distinct conclusion that the QSD-1 had a more more stable soundfield but it was also the less distinct & muddier than the other two. I think there is a benefit & certainly no harm done today with tri-band decoding as done in the SM. But back then it was just so much of medium quality circuits & components trying to do something complex that you gained in one area & lost some in another.

What method do you use for pre-synth?

 

[par4ken]

At one time I had a 2 band Photolume decoder, a QSD-1 & a QSD-2. I can't say as I remember the Photolume being more active than the other two. I do recall my distinct conclusion that the QSD-1 had a more more stable soundfield but it was also the less distinct & muddier than the other two. I think there is a benefit & certainly no harm done today with tri-band decoding as done in the SM. But back then it was just so much of medium quality circuits & components trying to do something complex that you gained in one area & lost some in another.

What method do you use for pre-synth?

Scott, I built your pre-synth circuit years ago, it's installed in a preamp that I don't really use any more, my tube based unit is far superior. I dragged it out storage and hooked it up to use the pre-synth. My Involve is installed inside of my Sony SQD-2010 with the outputs connected to the 2010's discrete inputs. I did that because there is so much extra room inside the 2010. I'm able to compare the 2010's RM decoding with Involve by pushing a button. I was actually amazed at how similar the two sounded. The biggest difference is almost no center breakthrough in the rear channels with Involve. I might swap the board with the SQ one for listening comparisons with the 2010, although I'm already sure that the Involve will sound better.
As for stable soundfield I believe that the Photolume is superior to the QSD-1 but the QSD-1 is more active and also a bit muddier. Multi banding is a strategy that makes more sense to me with DSP, but why stop at 3 bands, why not go say 10 bands or more? Digital processing adds a sight harshness to the sound compared with good analog, that's why I love the Photolume so much right now. The Photolume lacks the rear output phase shift (actually an all-pass filter rear referenced to the fount) as such Lf is out of phase with Lb while Rf is in phase with Rb. This doesn't seem to cause any problem with stereo enhancement, however it might be best to reverse the phase of Lb. Doing so will place center back out of phase, but there is no center back in a normal stereo signal. If any ambience is present in the stereo recording it would be reproduced with the same phase relationship as in the actual stereo mix.

 

[par4ken]

I will order the Involve SQ if I can ever get the discount code to work. I read that it is pretty much equivalent to the Audionics in performance, Quaddies who have bought one really like it. With the discount code, the Involve SQ V2 is half the price of the Audionics if you don't count inflation which has been substantial since 1978. So, the price is right. I think I'll just call them and order it over the phone. If you still prefer the Tate, I'd say let's put the two together and see if we can get a good one out of it, but then there would be this bloody fight over who gets to keep it. So, I will hang on to it, hoping someday I will have some way to ressurect it. It's been a good one, it served me since 1978, I will miss it. Audionics Space and Image Composer, serial 12132, R.I.P.

I haven't given up hope for my S&IC yet, it's sitting back on my workbench along with a pile of other projects. It's a little hard to trouble shoot when the Audionics schematics don't exactly match the board. I actually question the need for class A operation and the 2.2K value seems low compared to articles in "Audio Amateur" that as I recall they used values around 6-7K. The soft clip circuit is another puzzler, my V-, voltage is almost double what the schematics indicate. One drawing has the + and - values reversed. I tried to PM Steve Kennedy but no response, I hope that he is still with us. I haven't give up hope I know that there is another B.O. unit in town, maybe I can get my hands on it. Serial 12310 is on life support.

 

[Sonik Wiz]

Scott, I built your pre-synth circuit years ago, it's installed in a preamp that I don't really use any more, my tube based unit is far superior. I dragged it out storage and hooked it up to use the pre-synth. My Involve is installed inside of my Sony SQD-2010 with the outputs connected to the 2010's discrete inputs. I did that because there is so much extra room inside the 2010.

Haha etc... funny how hardcore audio DIY people look at a preamp, a decoder, or whatever box & see the potential for what it can be instead. One of the more successful & fun projects I did was to modify a Sansui QS-500B decoder for an input/output control center.

The 3 knobs on the left were used for 2 ch select, level, level balance & phase balance. The big decode knob on the right was used to select the 4 ch decoded output from Photolume QS, Ambisonic, Tate. And of course the balance & main level knob served original purpose. I removed the top plastic panel & replaced it with new plastic, kodalith windows for meters & new text for the knobs. The bottom panel was painted black & used press type lettering to denote new functions for the controls. Interestingly this project came about also because of the smell of smoke. The power amps fried & since I didn't use them anyway I found a new purpose for the unit. I gave it away to a friend when I moved to 5.1. Wish I had it today.

Multi banding is a strategy that makes more sense to me with DSP, but why stop at 3 bands, why not go say 10 bands or more? Digital processing adds a sight harshness to the sound compared with good analog, that's why I love the Photolume so much right now.

dts Neo 6 did it's thing with 12 bands in early units & 19 in later implementations. Can you imagine doing this in analog? DSP would be the only way but I disagree it adds a slight harshness if done right. Or maybe at my age I only have 14 bit ears.

A case can be made both for & against multi-band decoding. Bass from early audio days right up to now is generally mixed "center front." Meanwhile all fundamental notes in music are actually quite low with only pipe organs & synth/midis pumping out really high notes. Therefore the high frequencies would be upper harmonics of the fundamental notes & wouldn't they both be coming from the same direction? The benefit of tri-band decoding seem obvious but also it can be challenged.

I have often thought great approach would be 2 band decoding with simple decoding for bass, say <200Hz and variomatrix for the upper bands. That way the bass would have no concern of time constant control voltage filtering, simpler circuit of extremely low distortion & the bass would still be coming from the intended direction. It has the potential to put a bit more bass in the rears but that could be controlled & might be of benefit. Meanwhile the high pass signal could be treated to high separation variomatrix with well chosen time constants & no worries of ripple on the control voltages from the bass signal.

I agreee with you on the output phase shifting which was token at best in Sansui units. The QSD-1000 had a considerably better output phase shift. But doesn't matter much if playing stereo.

I think it's extra cool you are still using & liking the Photolume DIY kit. Think how improved it could be tuned up if the fixed resistors were replaced with pots for adjusting the control voltages?

 

[par4ken]

Haha etc... funny how hardcore audio DIY people look at a preamp, a decoder, or whatever box & see the potential for what it can be instead. One of the more successful & fun projects I did was to modify a Sansui QS-500B decoder for an input/output control center.
View attachment 48581

The 3 knobs on the left were used for 2 ch select, level, level balance & phase balance. The big decode knob on the right was used to select the 4 ch decoded output from Photolume QS, Ambisonic, Tate. And of course the balance & main level knob served original purpose. I removed the top plastic panel & replaced it with new plastic, kodalith windows for meters & new text for the knobs. The bottom panel was painted black & used press type lettering to denote new functions for the controls. Interestingly this project came about also because of the smell of smoke. The power amps fried & since I didn't use them anyway I found a new purpose for the unit. I gave it away to a friend when I moved to 5.1. Wish I had it today.



dts Neo 6 did it's thing with 12 bands in early units & 19 in later implementations. Can you imagine doing this in analog? DSP would be the only way but I disagree it adds a slight harshness if done right. Or maybe at my age I only have 14 bit ears.

A case can be made both for & against multi-band decoding. Bass from early audio days right up to now is generally mixed "center front." Meanwhile all fundamental notes in music are actually quite low with only pipe organs & synth/midis pumping out really high notes. Therefore the high frequencies would be upper harmonics of the fundamental notes & wouldn't they both be coming from the same direction? The benefit of tri-band decoding seem obvious but also it can be challenged.

I have often thought great approach would be 2 band decoding with simple decoding for bass, say <200Hz and variomatrix for the upper bands. That way the bass would have no concern of time constant control voltage filtering, simpler circuit of extremely low distortion & the bass would still be coming from the intended direction. It has the potential to put a bit more bass in the rears but that could be controlled & might be of benefit. Meanwhile the high pass signal could be treated to high separation variomatrix with well chosen time constants & no worries of ripple on the control voltages from the bass signal.

I agreee with you on the output phase shifting which was token at best in Sansui units. The QSD-1000 had a considerably better output phase shift. But doesn't matter much if playing stereo.

I think it's extra cool you are still using & liking the Photolume DIY kit. Think how improved it could be tuned up if the fixed resistors were replaced with pots for adjusting the control voltages?

I did add pots to the Photolume to adjust separation but it also worked well just with the fixed resistors. I was planning to add a pot to make the hall and surround functions adjustable as well, as you once suggested, I have a pot (dual 5K) for that purpose but haven't gotten around to installing it. I got my unit off eBay, I wanted the kit back in the day but couldn't afford it at the time.
Reading up a bit on circle surround it sounds like they basically leave the bass undecoded as you suggest and manipulate the mid highs, as you suggest.

 

[Sonik Wiz]

I did add pots to the Photolume to adjust separation but it also worked well just with the fixed resistors. I was planning to add a pot to make the hall and surround functions adjustable as well, as you once suggested, I have a pot (dual 5K) for that purpose but haven't gotten around to installing it. I got my unit off eBay, I wanted the kit back in the day but couldn't afford it at the time.
Reading up a bit on circle surround it sounds like they basically leave the bass undecoded as you suggest and manipulate the mid highs, as you suggest.

Circle Surround was uniqe for that time as it was intended to encode separate L/R rears instead of the single rear ch of Dobly matrix. There is some good info on Disclord's archive.

Much less is known specifically about dts Neo:6. No good white papers and all forum discussions or reviews is pretty superficial. I just found the relative patent 7283634 & figure 8 explains it all. It is quite elaborate & spreading it out over many bands is mind boggling. However it really doesn't seem like an optimum choice for stereo to surround. I do have it on my Anthem AMV 30 but I've never played with it. I might have to run some test tones & music through it tonight.

My apologies to The Quadfather for drifting off topic. I will cease & desist.

 

[The Quadfather]

I haven't given up hope for my S&IC yet, it's sitting back on my workbench along with a pile of other projects. It's a little hard to trouble shoot when the Audionics schematics don't exactly match the board. I actually question the need for class A operation and the 2.2K value seems low compared to articles in "Audio Amateur" that as I recall they used values around 6-7K. The soft clip circuit is another puzzler, my V-, voltage is almost double what the schematics indicate. One drawing has the + and - values reversed. I tried to PM Steve Kennedy but no response, I hope that he is still with us. I haven't give up hope I know that there is another B.O. unit in town, maybe I can get my hands on it. Serial 12310 is on life support.

 

[The Quadfather]

The V- voltage should be the same as the V+ voltage in the S&IC. About 15 volts I believe. If it's higher, or it doesn't match the + level, suspect a bad regulator pass transistor. That would be one of the big ones with the heat sink. Transistors have three pins. I imagine the voltage at the main filter caps is around 20 volts or so, plus and minus. It's not marked on the schematic, but the output voltage is clearly marked at 15. Across the + and the -, it will be 30 volts. Note that there is a note on the schematic about changing a resistor to make it +17volts and-13 volts. Not sure why you would do that. But Mine measures +15 and-15. It might have been a mod to make the Exar chips happier. Mine had National chips, except for the one that got replaced back in the day, Audionics didn't have any more National chips, and had to sell me an Exar chip. But it worked, and I was happy.

 

[The Quadfather]

Photolume? Never heard of it. I did go ahead and ordered the Sound Master V2. Now, it's a waiting game.

 

[par4ken]

The V- voltage should be the same as the V+ voltage in the S&IC. About 15 volts I believe. If it's higher, or it doesn't match the + level, suspect a bad regulator pass transistor. That would be one of the big ones with the heat sink. Transistors have three pins. I imagine the voltage at the main filter caps is around 20 volts or so, plus and minus. It's not marked on the schematic, but the output voltage is clearly marked at 15. Across the + and the -, it will be 30 volts. Note that there is a note on the schematic about changing a resistor to make it +17volts and-13 volts. Not sure why you would do that. But Mine measures +15 and-15. It might have been a mod to make the Exar chips happier. Mine had National chips, except for the one that got replaced back in the day, Audionics didn't have any more National chips, and had to sell me an Exar chip. But it worked, and I was happy.

Yes the V- and V+ should be 15 Volts but not the voltage to TL074 #2, it's powered from Dual opamp RC5558 and should read (according to the Matrix Schematic) +6 and -3, it also says to adjust for minimal offset? It's shown as -6.6 and +2.3 on the Misc. Diagram. Mine measures about -11.8 and +3V. It's been like that since I can remember, by shunting one of the resistors I can get it to -6V but oddly the resistor values are one tenth that shown on the schematic. Mine has the Exar chips, I think that the 2 (output chips) must be pin for pin compatible with the Nationals, but the Exar (detector chip) has less pins than the National that's shown on the schematic! Yes that change in the Power Supply voltage is rather odd, I don't think my original copy of the schematic carried that note. It would be nice if Steve Kennedy could clarify, but he hasn't posted for a long, long time.

 

[par4ken]

Photolume? Never heard of it. I did go ahead and ordered the Sound Master V2. Now, it's a waiting game.

The Photolum was sold assembled or as a kit it was featured in an issue of Popular Electronics (or might of been Radio Electronics) about 1976, I'll look it up and post a link.

 

[par4ken]

The December 1976 issue of Popular Electronics, with Photolume "Universal Decoder" construction details. https://www.americanradiohistory.com/Archive-Poptronics/70s/1976/Poptronics-1976-12.pdf

 

[Sonik Wiz]

The December 1976 issue of Popular Electronics, with Photolume "Universal Decoder" construction details. https://www.americanradiohistory.com/Archive-Poptronics/70s/1976/Poptronics-1976-12.pdf

Yeah I still have that issue magazine on my shelf downstairs. That was the most complex kit I had ever built at that time. It got me to up my game by pre-sorting all 10k resistors, 100k resistors, 1 mfd caps, etc. Check, double check & since I built two of them I would also compare & proof check between boards multiple times. The decode switch was a spaghetti mess of wires but I was lucky to find a rotary switch that fit the bill perfectly. It was RF quality, ceramic sections & gold plated contacts, very rare for back then. I pulled a couple of the Sansui chips out of one board to fix a friends QSD-2 so it would be a big deal to get going again.

 

[par4ken]

Yeah I still have that issue magazine on my shelf downstairs. That was the most complex kit I had ever built at that time. It got me to up my game by pre-sorting all 10k resistors, 100k resistors, 1 mfd caps, etc. Check, double check & since I built two of them I would also compare & proof check between boards multiple times. The decode switch was a spaghetti mess of wires but I was lucky to find a rotary switch that fit the bill perfectly. It was RF quality, ceramic sections & gold plated contacts, very rare for back then. I pulled a couple of the Sansui chips out of one board to fix a friends QSD-2 so it would be a big deal to get going again.

Yes it wasn't your everyday Heathkit! Working on mine, while replacing some capacitors I broke the back phenolic wafer, but was able to fix it with a bit of epoxy (the good 24 hour cure one, not that 5 minute garbage) and it's still holding fine. I have some of those military grade ceramic switches that I could/should replace it with, but it's not a simple job. I guess the reason that the SQ mode was not included in the QSD-1, was (in part) due to the complexity of the switching arrangement. Also I had to add new in/out jacks as the original phelonic strip jack set has the jacks mounted much to close together, it would only accept the cheapest cables, that way. Luckily after years of seemingly unavailability there are lots of the QS decoder chips for sale on eBay, many from Hong Kong and China. While the decoder does a good job with QS and SQ it really shines with stereo played in the surround mode. I think that the adage less is more is very true in this case. I should sit down and do more listening to the Involve but the Photolume sounds so good that I can hardly bear to disconnect it.

 

[par4ken]

The V- voltage should be the same as the V+ voltage in the S&IC. About 15 volts I believe. If it's higher, or it doesn't match the + level, suspect a bad regulator pass transistor. That would be one of the big ones with the heat sink. Transistors have three pins. I imagine the voltage at the main filter caps is around 20 volts or so, plus and minus. It's not marked on the schematic, but the output voltage is clearly marked at 15. Across the + and the -, it will be 30 volts. Note that there is a note on the schematic about changing a resistor to make it +17volts and-13 volts. Not sure why you would do that. But Mine measures +15 and-15. It might have been a mod to make the Exar chips happier. Mine had National chips, except for the one that got replaced back in the day, Audionics didn't have any more National chips, and had to sell me an Exar chip. But it worked, and I was happy.

You got me thinking about the + and - 15 Volt supply, I seem to recall at one time when I decided to replace the power supply filter capacitors, finding that the supply voltages were odd, possibly +17 and -13 so I tweaked the supply to give exactly 15 Volts on both rails. It did still seam to work properly after that though, but might have something to do with the incorrect soft clip circuit voltage, that I'm seeing.