Sansui QSD-2: Need help with parts list

[kissklas]

Hello guys,

Does anyone have a list of electrolytic capacitors for the Sansui QSD-2 boards laying around? I need to do a recap and the only manual I have found only has the part list for the power supply board, the rest is missing. Here is that list btw:

I did find lists for the F2087 and F 2088 boards in the QRX-9001 manual, but who knows if they did any changes between the QRX-9001 and QSD-2. Besides, this manual only seem to list what I guess must be the film capacitors, which doesn't really help:

If anyone can help out, it would save me a great deal of faceplanting the circuit boards to read the values and map it out for myself

 

[kissklas]

Alright, update!
The QRX-7001 manual seems to have a full list of capacitors. The transistors and film caps, plus the schematic drawing lines up with the QRX-8001/9001 manual. It starts to look like the same board between these two amplifiers at least. So I reckon it could be the same for the QSD-2 as well? At least this makes it easier to cross check it with the boards themselves, but still, if anybody knows feel free to chime in

 

[par4ken]

I recommend using "Wima" film type capacitors. They are about the same size as the old electrolytic capacitors that they will be replacing. They will not only improve the overall sound quality but will not degrade requiring future replacement. Don't worry if the voltage rating is higher than that of the original capacitor, both 50V and 63V versions are very common.

 

[kissklas]

I recommend using "Wima" film type capacitors. They are about the same size as the old electrolytic capacitors that they will be replacing. They will not only improve the overall sound quality but will not degrade requiring future replacement. Don't worry if the voltage rating is higher than that of the original capacitor, both 50V and 63V versions are very common.

Yeah i had a look at the lists and there are lots that can be replaced with film caps for sure. Wima... Brand? I'll check them out!

 

[par4ken]

Yeah i had a look at the lists and there are lots that can be replaced with film caps for sure. Wima... Brand? I'll check them out!

Yes, you can find them on eBay as well as from distributors such as Digi-key.

 

[kissklas]

Yes, you can find them on eBay as well as from distributors such as Digi-key.

Usually use mouser or elfa here. I'll check them first. Btw, any chance of getting 47 and 100 uf film ones in a decent size, or should i just keep those electrolytic?

My speaker filters are now oil drums with a tiny bit of circuitboard, so I know they can get quite... sizeable

 

[par4ken]

Usually use mouser or elfa here. I'll check them first. Btw, any chance of getting 47 and 100 uf film ones in a decent size, or should i just keep those electrolytic?

My speaker filters are now oil drums with a tiny bit of circuitboard, so I know they can get quite... sizeable

You are unlikely to find larger values that will fit so just keep them as electrolytic. Special audio grade electrolytics are available, do they sound better? I can't say for sure but I personally like to use them anyway.

 

[kissklas]

You are unlikely to find larger values that will fit so just keep them as electrolytic. Special audio grade electrolytics are available, do they sound better? I can't say for sure but I personally like to use them anyway.

Yeah i see some of the caps are specified in the list as low noise and so on, so i suppose this was a thing back then especially in the signal path. I usually go audio grade as well. Often its not a big economic sacrifice anyways so why not worst case there is little improvement rather than a lot.

 

[Sonik Wiz]

Yeah i see some of the caps are specified in the list as low noise and so on, so i suppose this was a thing back then especially in the signal path. I usually go audio grade as well. Often its not a big economic sacrifice anyways so why not worst case there is little improvement rather than a lot.

Hello Klas!
About a hundred years ago I wrote an article for the MCS Review titled A Vario-Matrix Survival Guide. @par4ken was kind enough to scan & post it on the forum some time back. It might be helpful, or at least interesting to read:

https://www.quadraphonicquad.com/forums/threads/a-vario-matrix-survival-guide.30363/
I dunno why QSD-2 schematics or service manuals are so hard to find. It's easy to track down the QSD-1 & various Sansui quad receiver info but not the D2. I'm sure it was the most popular stand alone Sansui decoder. But good luck with your project & keep us informed!

 

[kissklas]

Hello Klas!
About a hundred years ago I wrote an article for the MCS Review titled A Vario-Matrix Survival Guide. @par4ken was kind enough to scan & post it on the forum some time back. It might be helpful, or at least interesting to read:

https://www.quadraphonicquad.com/forums/threads/a-vario-matrix-survival-guide.30363/
I dunno why QSD-2 schematics or service manuals are so hard to find. It's easy to track down the QSD-1 & various Sansui quad receiver info but not the D2. I'm sure it was the most popular stand alone Sansui decoder. But good luck with your project & keep us informed!

Yeah there is only one single service manual scan available online, and the part lists and circuitboard drawings are missing. Just the power supply and the rest is a black hole. And some services charge you for this lacking, freely available manual! Talk about robbery... But if the 7001 has the same boards with the same components i guess that'll do.

You wrote that? I had a peak already as it pops up frequently when i fall down the quad rabbit hole on google but I'll have another read!

I'll report back with results for sure

Thanks for chiming in on the thread!

 

[par4ken]

Looks like all the available manual copies are from the same original source and all are missing pages! The schematic does show the circuit boards and the parts values. You can easily make your own parts list. Remember that often buying parts is like buying beer, cheaper in larger quantities. Don't be afraid of ordering a few extras!

 

[kissklas]

... that often buying parts is like buying beer, cheaper in larger quantities. Don't be afraid of ordering a few extras!

You havent been to Norway have you

Oh yeah the schematic is complete atleast! that helps

 

[kissklas]

By the way, does the QSD-2 built for modern line level values as input? My devices are of an older standard which is quite a bit lower. It's a simple conversion on the amp side though.

 

[MidiMagic]

Modern line levels???

Consumer equipment usually runs at -10 dBV.
Professional equipment usually runs at +4 dBu.

 

[par4ken]

The decoder should be fine even with pro level input signals. The specification of 130 mV is nominal, used only to show compatibility with consumer equipement at the time. Back then figures of 100 mV were often quoted as line level. As I seem to recall that level might have even been an European DIN standard. Also the 100 mv figure is shown as nominal for the QSD-1.

Using the figures supplied by MidiMagic -10 dBV = 316 mV and 4.0 dBu = 1.228 V.

My testing of the Photolume decoder (QSD-2 clone) showed no visible distortion of the output until the input exceeded about 1.3V rms.

Many CD players nominally output 2.0V so could conceivably overload the unit if left unattenuated.

 

[kissklas]

Modern line levels???

Consumer equipment usually runs at -10 dBV.
Professional equipment usually runs at +4 dBu.

The decoder should be fine even with pro level input signals. The specification of 130 mV is nominal, used only to show compatibility with consumer equipement at the time. Back then figures of 100 mV were often quoted as line level. As I seem to recall that level might have even been an European DIN standard. Also the 100 mv figure is shown as nominal for the QSD-1.

Using the figures supplied by MidiMagic -10 dBV = 316 mV and 4.0 dBu = 1.228 V.

My testing of the Photolume decoder (QSD-2 clone) showed no visible distortion of the output until the input exceeded about 1.3V rms.

Many CD players nominally output 2.0V so could conceivably overload the unit if left unattenuated.

Been told this is an old DIN norm, my guess is for tape recorders. I think they may have stopped using it around the same time my amp was made. The Huldra 10 has it on tape out and AUX, the TR1000 from around the same time has not. From what I can find it's supposedly 8 times lower than todays standard. Really annoying when switching between sources anyways, so if the QSD-2 is made with similar values to modern stadards in mind, I think I'll convert both amps as well as recap

 

[Robkyle]

The Popular Electronics QS decoder kit is a virtual clone of the QSD-2. Exactly the same schematic, Although I have not gone through the parts list, there is no reason to believe it isn't the same capacitor values. You can try to find what you are looking for here.

 

[Robkyle]

Hello Klas!
About a hundred years ago I wrote an article for the MCS Review titled A Vario-Matrix Survival Guide. @par4ken was kind enough to scan & post it on the forum some time back. It might be helpful, or at least interesting to read:

https://www.quadraphonicquad.com/forums/threads/a-vario-matrix-survival-guide.30363/
I dunno why QSD-2 schematics or service manuals are so hard to find. It's easy to track down the QSD-1 & various Sansui quad receiver info but not the D2. I'm sure it was the most popular stand alone Sansui decoder. But good luck with your project & keep us informed!

Sonik Wiz,

Scott Varner???

 

[chucky3042]

The Popular Electronics QS decoder kit is a virtual clone of the QSD-2. Exactly the same schematic, Although I have not gone through the parts list, there is no reason to believe it isn't the same capacitor values. You can try to find what you are looking for here.

We have the Sansui chips!

 

[Sonik Wiz]

Sonik Wiz,

Scott Varner???

Yes. Yet another part of me exposed on the Interweb. Do I know you from a previous life? If so I apologize for what ever it was I did...