Newb 6001 mods help

[gazmono]

Hi!
I am new to this forum. I live in the UK (London) and I have just bought a Sansui QRX6001. It hasn't even been posted to me yet, but i have become obsessed with Quad sound already.
When I was about 13 I went to a friends house and was amazed by his dads Quadraphonic system. It was my only brush with Quadraphonics in the flesh. I had only read about it before, Quad was extremely rare in England, it never got as far as in the States.
Now I am about to have my own system I can hardly believe it.
I settled on getting a 6001 after reading an article by progrockasaurus on rateyourmusic.com.
It seemed a good buy coz it has the same decoders, (although I have since learned, a different CD-4 decoder) as the 9001, but is more reliable and a hell of a lot cheaper and lighter.
I am used to doing electronic work and am expecting to have to spend time getting it up to scratch, even though the e-bay seller says it 'works well'.
I am going to recap it myself. Having read a lot on your threads I am convinced it is a good idea to recap fully. I have downloaded a service manual already( isn't the internet great for this?)
This is where i could do with advice on what else I should do to improve/bring back to scratch the performance.
I was wondering if I could get a 9001 CD4 decoder PCB (I think I remember seeing one on e-bay) modify it to 'Holy Grail" status and either replace the 6001's decoder or use it as an external decoder. If this is not possible, are there any mods I can do to improve the 6001's demodulator?
I have spent oceans of time on this forum at work and I think I need to ask you guys to point me in the right direction before i get into trouble.
Thanks for your time.

 

[Quadrockasaurus]

G'day Gazmono...and welcome to QQ....You've posted your first post in one of the quietest section's of QQ...I almost missed this, and I tend to spend most of my time in the Hardware Section.

That's my list you found out there on RYM. Notice the resemblance..."Progrockasaurus"..."Quadrockasaurus"....anyway... my suggestion is that you start with the basics and get you unit up and running before you start thinking mods. A basic re-cap. Maybe check the voltages for the QS Synth circuit so that it functions properly. There's a major Quad site on the web which gives you info on how to do this here...Saving the Sansui...However, if your absolutely intent on doing some modding....then rebuild the Phono Stage in the 6001, which is very average. It doesn't look too complicated....but I'm saying that as a novice where the tech stuff is concerned. I've done a bit of re-capping, but very basic stuff. Maybe some of the other guys can chime in at some point on the tech stuff. As it stands, my intermittent 6001 is now out of action, and in need of a full re-cap as well, and it looks like a LOT of work....

I'm glad that site of mine has pointed at least one person in the right direction, I've noticed brief mentions of at least a couple of folks here on QQ going back from the (..very nice) but pain in the ass, expensive to fix, 9001 & 8001 units to the simpler 7001 & 6001's and I think those units are the best place to start your Quad collecting career....I wouldn't fret too much with a CD4 mod to start, just try to get the QS synth working right. That's really (..I think) the best part....It'll floor you how great some music can sound decoded through the QS Vario-Matrix.

Good luck on your Re-cap.
Cheers.

 

[gazmono]

Thanks mr. Saurus. I wondered why I was getting no replies. I will start with re-capping. Thanks for the advice about voltages in the QS cct. I am interested to hear for myself what it sounds lik. As usual on forums there are some very opinionated people with opposing ideas. I like your helpful friendly stance.
As for the phono stage I was intending to use my Naim pre-amp for that. Does the CD-4 cct only work with the onboard phono stage or are there line inputs?
Thanks for the help.
Gaz

 

[Quadrockasaurus]

You can connect a Phono stage to the AUX input of the 6001 and it should decode whatever goes in. (I use a Creek OBH-15 or My JVC 4DD-5 CD4 Decoder which has a built in Phono Stage). Note however that you need a turntable setup that will pick up the high CD4 carrier frequencies on the vinyl to decode the CD4 format....a line contact stylus with a cart that has a wide frequency response up 50Khz...like a Audio Technica AT440 Mla (...A Current Model) should do the trick. You'll need to find a CD4 setup record (ebay) to properly set-up that format on the 6001...or if you can't...do the best you can with the link to this page on QQ which gives you some info on how to set up CD4...Proper Adjustment of a CD-4 demodulator

QS/SQ & QS Vario-Matrix don't require a special stylus....any one will do.

Note also...that If you want to record internally decoded Quad you can't do it from the Quad recorder inputs/tape loops in the 6001 (Note that I've never had a quad recorder to test this....but it's common knowledge). It'll record a DISCRETE or Decoded Quad signal (External Decoder) via the AUX input...but not an internally decoded one. You can get around this by recording internally decoded quad from the 6001's HEADPHONE Connections to an external Quad recorder....a pain, and confusing...@:...yep...but that's how they set it up on the whole range.

I'm not too familiar with the Naim stuff, but I'd test your pre connected at LOW volume to the AUX to start, just to make sure everythings compatible.

Cheers.

 

[gazmono]

Can you suggest where i can get a good CD-4 cartridge? I am having trouble finding the recommended AT20sla. Searches on google yield little.
I have just found a place in England selling old, but unused Empire quad cartridges; the 440D for less than £50 (around $80). Do you know how good these are? Is there a site that compares quad cartridges?

 

[Quadrockasaurus]

Old secondhand cart's are a bit unpredictable...you don't know what you gonna get, or if you can get a replacement stylus for them. I've never tracked down a vintage Quad cart as my original AT140LC just happened to have the right stylus profile (Shibata/Line Contact) and Freq Response (..its the great grandaddy of the current 440Mla). I'd just get a current model cartridge with a Line contact stylus....like the current Audio Technica AT440 Mla...that one I know works. Although the new Freq response spec for those would suggest it doesn't....they actually do work. There's a few of them being sold new on ebay, including some sellers from the UK. The cheapest of those I've seen is about 140 UK Pounds.

Lacking that....there's some more info here on CD4 carts and specs on QQ so that you can track a recent one down with the right specs yourself...Confused about CD-4 Gear - will a modern cartridge with shibata work

 

[tracker-x]

Hi!
I am used to doing electronic work and am expecting to have to spend time getting it up to scratch, even though the e-bay seller says it 'works well'.
I am going to recap it myself. Having read a lot on your threads I am convinced it is a good idea to recap fully. I have downloaded a service manual already( isn't the internet great for this?).

old thread worth reviving- I'm still researching these 6001's and to be honest, don't recap them. a much better approach would be, re-transistor them. the small driver and final transistors are the culprits, not the caps ! and you'd probably be installing inferior caps compared to what was OEM