thestig
New member
- Joined
- Jul 9, 2009
- Messages
- 3
Hi all!
Long-time 'lurker', first-time poster. I've been fascinated by quad ever since I was a kid, but it was really the comparatively-recent advent of multi-channel home cinema (and DVD-A/SACD) that has truly sparked my interest in the subject. My AVR, like many others, has analogue inputs to which quad sources can be attached - rearrange the speakers into the traditional quad configuration, and enjoy! I had an old Sony SQA2020 that was sitting in a shed for years, having been given to me by a friend who was moving house. This needs restoring, and then I'll be able to play some of my old vinyl records encoded in the format (my old DSotM is the SQ release) and some of the CDs that preserve the matrix encoding. I might also experiment with some of the Audition decoding scripts that have been discussed here. Another acquisition was a JVC 1202 Q8 player, which I recapped, cleaned and demagnetised - the drive belt also needed replacement. The reason I finally got round to dealing with this was the chance discovery of a shrinkwrapped Q8 copy of Donald Byrd's iconic Black Byrd album (to the best of my knowledge, only currently available on 2-channel CD). I have to say that Q8 sucks in terms of sound quality; it's 'compressed' and hissy although the channel separation of this discrete format can be good if the vertical head alignment screw is adjusted properly. My sample had lots of 'clicks', which I attribute to static building up on the tape's slippery back-coating and discharging on the playback head. In the end, I disassembled the cartridge, and transferred the reel to a better-quality Scotch-brand 'blank' shell (which had sprung pressure-pads). The result was much better, and I was able to transfer the four audio channels to a PC equipped with a professional soundcard and use audio editing software to reduce the noise and restore a bit of high-end 'sparkle'. I'm pleased with the result, even on a high-grade home cinema system. I guess that for tape the Q4 format was the one to go for - but these reels are very rare in the UK (they're certainly less common than the 4-channel decks, notably the Teac 3440, needed to play them on). Some of the Q4-to-DVD-A conversions I've heard are superb.
But my next project is discrete vinyl. I have a few CD-4 albums, and a Philips cartridge (GP412) with '4-CH' (Shibata) stylus that I've had for many years (in the mid-80s, a local electronics broker had acquired Philips' entire stock of cartridges and stylii and was selling them on very cheaply - wish I'd bought more of that stuff now!). Apparently, Philips was hedging all its bets on the CD format it had developed in conjunction with Sony; CD players were however prohibitively-expensive to a teenager back then. The final part of the jigsaw is a Denon UDA-100 UD-4 'disc demodulator', which was acquired cheaply at a recent audiojumble. Although its main goal was to decode rarer-than-hen's-teeth UD4 discs, this box will also deal with CD-4 recordings (it does SQ/QS matrix too, albeit in basic non-logic form and so I'm not bothered about those - computer-based decoding will be far superior). I haven't tried it yet, and before powering it up I'll replace the electrolytics in the power supply. But does anyone have any instructions (how to set the separation controls without a test disc) or servicing information on this unit? There's nothing of any real use on the Internet! A schematic would allow me to investigate the possibility of modifying the circuitry for better performance (after all, it was not optimised for CD-4). One of the members of this forum produced an excellent guide to modifying a JVC CD-4 demodulator - but I don't have one of those, and CD-4 demodulators don't exactly crop up regularly on eBay UK (and being on a tight budget, I'm not paying large amounts of money to ship items from the US!). Here's an example of my thinking: To avoid paying more license fees to rival format developer JVC than was necessary, might Denon have 'skipped' on the ANRS noise-reduction circuitry that CD-4 uses for the rear channels - and instead used a simple 'top-cut' filter? ANRS does much the same job as Dolby B, and I have (ironically!) a high-grade JVC Dolby B/C noise reduction unit that was sold for use with reel-to-reel decks. If any such filters in the rear-channel paths are disconnected, the rear channel outputs could be passed through the Dolby unit thereby correctly-reversing the encoding process.
Congratulations if you've made it this far. But can you help with manuals?
Stig
Long-time 'lurker', first-time poster. I've been fascinated by quad ever since I was a kid, but it was really the comparatively-recent advent of multi-channel home cinema (and DVD-A/SACD) that has truly sparked my interest in the subject. My AVR, like many others, has analogue inputs to which quad sources can be attached - rearrange the speakers into the traditional quad configuration, and enjoy! I had an old Sony SQA2020 that was sitting in a shed for years, having been given to me by a friend who was moving house. This needs restoring, and then I'll be able to play some of my old vinyl records encoded in the format (my old DSotM is the SQ release) and some of the CDs that preserve the matrix encoding. I might also experiment with some of the Audition decoding scripts that have been discussed here. Another acquisition was a JVC 1202 Q8 player, which I recapped, cleaned and demagnetised - the drive belt also needed replacement. The reason I finally got round to dealing with this was the chance discovery of a shrinkwrapped Q8 copy of Donald Byrd's iconic Black Byrd album (to the best of my knowledge, only currently available on 2-channel CD). I have to say that Q8 sucks in terms of sound quality; it's 'compressed' and hissy although the channel separation of this discrete format can be good if the vertical head alignment screw is adjusted properly. My sample had lots of 'clicks', which I attribute to static building up on the tape's slippery back-coating and discharging on the playback head. In the end, I disassembled the cartridge, and transferred the reel to a better-quality Scotch-brand 'blank' shell (which had sprung pressure-pads). The result was much better, and I was able to transfer the four audio channels to a PC equipped with a professional soundcard and use audio editing software to reduce the noise and restore a bit of high-end 'sparkle'. I'm pleased with the result, even on a high-grade home cinema system. I guess that for tape the Q4 format was the one to go for - but these reels are very rare in the UK (they're certainly less common than the 4-channel decks, notably the Teac 3440, needed to play them on). Some of the Q4-to-DVD-A conversions I've heard are superb.
But my next project is discrete vinyl. I have a few CD-4 albums, and a Philips cartridge (GP412) with '4-CH' (Shibata) stylus that I've had for many years (in the mid-80s, a local electronics broker had acquired Philips' entire stock of cartridges and stylii and was selling them on very cheaply - wish I'd bought more of that stuff now!). Apparently, Philips was hedging all its bets on the CD format it had developed in conjunction with Sony; CD players were however prohibitively-expensive to a teenager back then. The final part of the jigsaw is a Denon UDA-100 UD-4 'disc demodulator', which was acquired cheaply at a recent audiojumble. Although its main goal was to decode rarer-than-hen's-teeth UD4 discs, this box will also deal with CD-4 recordings (it does SQ/QS matrix too, albeit in basic non-logic form and so I'm not bothered about those - computer-based decoding will be far superior). I haven't tried it yet, and before powering it up I'll replace the electrolytics in the power supply. But does anyone have any instructions (how to set the separation controls without a test disc) or servicing information on this unit? There's nothing of any real use on the Internet! A schematic would allow me to investigate the possibility of modifying the circuitry for better performance (after all, it was not optimised for CD-4). One of the members of this forum produced an excellent guide to modifying a JVC CD-4 demodulator - but I don't have one of those, and CD-4 demodulators don't exactly crop up regularly on eBay UK (and being on a tight budget, I'm not paying large amounts of money to ship items from the US!). Here's an example of my thinking: To avoid paying more license fees to rival format developer JVC than was necessary, might Denon have 'skipped' on the ANRS noise-reduction circuitry that CD-4 uses for the rear channels - and instead used a simple 'top-cut' filter? ANRS does much the same job as Dolby B, and I have (ironically!) a high-grade JVC Dolby B/C noise reduction unit that was sold for use with reel-to-reel decks. If any such filters in the rear-channel paths are disconnected, the rear channel outputs could be passed through the Dolby unit thereby correctly-reversing the encoding process.
Congratulations if you've made it this far. But can you help with manuals?
Stig
