Hacking my QSD-1

[QSD-1]

OK, I got my QSD-1, the schematic, my diagonal cutters. Which blend resistors do I clip? I see one connected to the mode switch (R603), some in the Phase Shifter (R05, R11, R12, R15, R16). Are there others I haven't found yet?

So what's the pros and cons of taking out the blend resistors? Will I end up with more bleeding, jumpy localization?

I gotta ask, why would Sansui go to all the trouble to create circuits with great separation, then blend the source till it's practically mono. I must be missing something!

Thanks,
Gary

 

[mtgc]

You have to ask QuadBob about this. He is the acknowledged master of Sansui circuitry.

MTGC (Michael)

 

[ESD Buddy]

Hi,

I guess the schematic is like reading Egyptian for you.

Since I dont have a QSD-1 yet; Let alone have the schematic, I cannot tell you where they are. Please do not do this blindly, you can damage your amp section if you cut the wrong resistor. Also RatShack has a cheap soldering iron. It is best to remove them and keep em in a baggie. There are those who prefer non modified sets (with the everyone wanting to do such, it makes some wonder about longevity).

One thing to note... Blead resistors were to make stereo sound better, since it is not 4 channel. Some like to have the best separation for there Quad stuff and don't care about the stereo imagery being shifted equally.

Its all in one's taste... not everyone hears the same way, and likes the same format if you will.

 

[QSD-1]

ESD Buddy, no worries mate, for the last 40 years I have been an electronic designer.

I work on electronic equipment daily and I have found that clipping the component is the best way to prevent harm to the circuit board. If you do have to remove the component leads, they come out so much easier without a component between them. Of course, you should be certain that you have a replacement available.

I do agree with you wholeheartedly that you can pop those semis pretty easily by randomly modifying equipment. Even if you don't disturb bias, there is always the possibility that you will destabilize the feedback and end up with an output stage melting oscillation in the case of power amplifiers as an example.

The QSD-1 is pretty complicated, hence it is non-obvious which blend resistors people like to eliminate to improve performance. In particular, there is a rather odd frequency sensitive blend network between R & L at the input to the 90 degree phase shifters.

Thanks for the warning, though. You can never be too safe when working on semiconductor equipment. Just your name 'ESD' gives me shivers. Oh, the insulated gates I have lost to ESD. And I guess I just can't help but tell a scary story about an ESD exploit. It's the kind you tell around the campfire (grin).

I had spent some time setting up a computer with all the components laying out flat on the bench. I must have scuffled across the rug, because when I touched the Motherboard I heard a small snap. I musta gotten a little stupid, cause I said to myself "What's that red LED light coming out of the CPU ceramic lid?" and touched it absent mindedly. Did you know that flesh sticks tight to red-hot ceramic? I do now!!!

Gary

 

[ESD Buddy]

Hi,

Thanks for the reply... I too am a electronics major. Just never found anything to do as a hobby until lately. Believe it or not I was the only guy in California that worked on PC's and servers that did not have a PC at home let alone a server or two. Now that I see alot of throw away electronics even at a $1,000 or so (JVC HRS9800) in 2000 is a throw it away after death item; I come to realize the good stuff was in the 70's though it is outdated.

I am in progress of combining Sansui QRX 7500 with 01 boards and a older Qsound processor for testing (slow process, surfacemount technology is a pain, plus the processor I want is very hard to get unless your in China... anyone with connections???). Just because it is not digital and stays in the analog domain and it will be truely unique. I have yet to find a direct need for more than 4 speakers, Qsound processors do very well at 3D that I have to tame them down a bit... kinda like shopping for a TV at Circuit City and finding that all the contrast and brightness is way up on all the screens.

My reason is that our hearing is just like our sight... 1 ms glitch in sound cannot be heared by anyone. So it is trivial to go with High Def audio when all you need is clean well produced analog audio. Sorry to say my TDK Type IV tapes beat digital until you start to pay $2,000 or more in your digital equipment. Besides I can fix anything that is not LSI packaged.

Note: QRX 7500 is so well put together it is almost a shame to change it... Wonder why so many think Marantz 4400 / 4300 series is so good?


Well good luck, I am still waiting on QuadBobs help (may be done before he reads my post and email)... you can email him directly at [email protected]

C-ya