Fairly well known on QQ. Since the SM does not use these chips the reason why you have a quantity of these could be most interesting.
Sansui QSD-2: Need help with parts list
- Thread starter kissklas
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R&D
Rumors are flying that Involve is working on a CD-4 Demodulator, my sources are private so can't say more.
Any road luvs...
Well, yes, but what does that have to do with Sansui Vario-Matrix chips?
My guess is in that they were used in the research and development process. They could have gotten a deal on buying them in quantity.
The more sinister possibility is that they wanted them removed from the market place so that the vintage decoders would be unserviceable.
As true Quad lovers I doubt that they would've had that motive in mind!
Years ago people were asking for this. Chucky seemed open to the idea. I don't think that it would be a money maker though. A very complex design and a very limited market. It would be cool if it happens though. The last attempt at a modern demodulator was from Lou Doran but sadly he passed on.
Robkyle
Member
Robert Kyle. We exchanged letters in the 80's when I was in Charlottesville at UVA. I was building the Popular Electronics decoder at the time among other things and you advised me on changing the fixed resistors to variable to fine tune it. I frequently mention your name when I'm talking about quad to new people. Or if I'm telling the story about buying the QS encoder when I toured KM Records in Burbank that summer Didn't know you were still around.
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Hi Sonik
Around 12 years ago, I wanted to trial them against the digital stuff. Also remember the first proto boards were discrete analogy chips (never did solve the squeaky VGA problem). Actually never used the sansui chips but I wanted them just in case.
Re CD 4 still aim to do it but Dave keeps on getting distracted. He has the attention span of a gold fish
Hello again! Done recapping the matrix board and the phase control board now. Just now listening to a record to check it out. Always fun to hear how the caps change little by little after replacement. Was pretty modest and flat at track one, and now my the end of side two the depth and detail is blooming more and more. Ahhh, audio joy!
One thing I do fear, is that a transistor on the SQ part of the matrix board is failing. I have some volume independent intermittent crackling on the SQ program only. And so far the recap hasn't fixed that issue.
I'm going to keep on recapping the power board, and deal with the amp line level before trouble searching it but, if anyone knows, how is the availability of these transistors or alternative replacements?
One thing I do fear, is that a transistor on the SQ part of the matrix board is failing. I have some volume independent intermittent crackling on the SQ program only. And so far the recap hasn't fixed that issue.
I'm going to keep on recapping the power board, and deal with the amp line level before trouble searching it but, if anyone knows, how is the availability of these transistors or alternative replacements?
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The good ol BC337 will do fine
Cheers! Sounds like that could save me a lot of searching. I suppose the F and G suffixes are some kind of gain rating or something? Will the BC337 be a good sub for both?
And is the pinout the same, or do i have to give it some shiny new rubber trousers and cross its legs?
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OK for pin compatibility try this lot:Cheers! Sounds like that could save me a lot of searching. I suppose the F and G suffixes are some kind of gain rating or something? Will the BC337 be a good sub for both?
And is the pinout the same, or do i have to give it some shiny new rubber trousers and cross its legs?
It really is a very standard audio NPN with a gain of around 150. With the BC 337 the base is in the middle, so the above would be better
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Nah, the BC549 is pin compatible and available everywhere
Sounds good! Cheers, I'll have a look!
Why you say that? Cuz actual SQ decoders have a dozen phase shift transistors & the Sansui only one for SQ?
I understand. Most anything accomplished by Vario-Matrix whether it's stereo synthesis, SQ decoding, or QS decoding can be done simpler than dedicated SQ decoders. I mention the latter because Sony had a variable-matrix decoder patented like the Tate DES patent did for QS .
L+R is summed to go to the base of TR08. The C/R combination has a phase shift at a certain frequency (sorry I'm not gonna look it up) & going into TR12 you get a same/inverted signal at that phase shift. In the Sansui PM system left/right directional coefficients are fixed because SQ doesn't need L/R enhancement. However the phase inverted signal goes to HA1328 matrix chip & the in phase (shifted) signal goes to the HD3103 gain control chip.
This means SQ decoding for L/R was fixed in the PM decoding by Sansui & it did smooth push/pull blend to enhance center front to center back.
Oh, sorry to post such ramblings. Yes the transistors used are set for unity gain. Follow @chucky3042 suggestions.
Edit: Sorry. I think I misinterpreted the context of your line I quoted. Yes, probably those two little critters don't like Mike if everything else is fine.
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Hehe yeah I only ment that one of those transistors possibly makes my SQ program pop and crackle, preventing me from listening to Mike comfortable in SQ. Other that that, the little SQ decoding i have actually heard between the crackle has been superb. They state a 12 db separation compared to much higher figures on QS, but to be honest I'm content and very impressed indeed.
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Perhaps those two transistors have succumbed to the new COVID Ommadawn variant....
Like there isnt enough... Crises.. these days
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