Mike Dubay Posted July 30, 2010 Share Posted July 30, 2010 First would like to thank Dave Harris for the inspiration for this project. Dave modified a Behringer DCX-2496 by replacing the solid state op amps with a valve output stage. So nothing new here, just my implementation of the idea. I have been looking to upgrade my down stairs CD player, the current Sony unit is nice, but not great. I had some spare parts laying around, so I order a couple of torroidal transformers, and picked up a used CD player from the local record store for $20. Similar to Dave, I isolated the analog output from the A to D chip by some careful cutting of traces. This chip actually had balanced outputs, but I used just one from each channel. The first attempt work well as a prototype, but upon final assembly the delicate solid state electronics had died. The second attempt the valve equiptment was housed in a remote box. Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted July 30, 2010 Author Share Posted July 30, 2010 The parts include: 6 and 240 volt triad torroidal power supplies. DC heater supply. Valve is mounted on a blank aluminum switch plate. Stand offs are CPVC pipe with 4 inch long bolts inside. The system is point to point hand wired. The tube used is a 6n2p, readily avalabile, good sound and low price, I paid about $5 with matched sections. The cover and front panel are being fabricated. Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted July 30, 2010 Author Share Posted July 30, 2010 So did some quick initial listening sessions. Compared to my solid state Sony the hybrid JVC gave superior imaging, a dramatic difference. Instruments are located at a rock solid point in the sound stage. There is an improvement in midrange clarity, less harshness of vocals. Dynamics are about the same. A very satisfying mid summer project. More pics to come when case is complete. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted July 30, 2010 Share Posted July 30, 2010 very cool. Quote Link to comment Share on other sites More sharing options...
soundbound Posted July 31, 2010 Share Posted July 31, 2010 Nicely done. Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted July 31, 2010 Author Share Posted July 31, 2010 Here we are with the cover in place and the front black walnut face. Will add a red lamp on the front face to indicate the unit is on. I do this on my DIY stuff for safety, a bright red lamp indicates that the unit is still on. The subtle red glow of the tubes can be missed, esp after a few beers in the evening. Some more extended listening tomorrow night, have in-laws paying a visit today. I also figured out how to reduce the image size for those who don't have fast high speed. Quote Link to comment Share on other sites More sharing options...
Boxx Posted July 31, 2010 Share Posted July 31, 2010 What a skillful project... Great job... Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted July 31, 2010 Author Share Posted July 31, 2010 Thanks! There will be some other things I want to do. There is a slight 500 hz hum, I want to try my hand a regulated power supplies for both heater and valve sections. After this works well, then will search for a used CD player with a higher quality A/D converter. There is a used Nakamichi right now in my local used record store, but the price is marked half way to a new Marantz. I posses an older used Sony with Burr Brown A/Ds, that might become the next donor unless the Nakamichi get reduced drastically in price. Will also like to do some 1 on 1 testing against a Shanling, see where this would need improvements and how it measures up to a world class CD player. Might just have to pay Kevin from flint a visit. Quote Link to comment Share on other sites More sharing options...
kevinmi Posted July 31, 2010 Share Posted July 31, 2010 Come on down to Flint anytime! I'm working Monday thru Friday 5pm to 4 am, but still have Sat. and Sundays off. Quote Link to comment Share on other sites More sharing options...
Tarheel Posted July 31, 2010 Share Posted July 31, 2010 Very nice work Mike[Y] Quote Link to comment Share on other sites More sharing options...
Mike Dubay Posted July 31, 2010 Author Share Posted July 31, 2010 Come on down to Flint anytime! I'm working Monday thru Friday 5pm to 4 am, but still have Sat. and Sundays off. Great, will drop you a line when my schedule frees. I love doing A/B type testing to look for small tweaks. First half of next weekend I will be doing some fly fishing, but maybe next Saturday or Sunday. Listening to Tom Petty's new CD right now. Maybe a slight improvement in dynamics over my solid state CD players. What tubes are you running on the Shanling now? The bugle boys? Quote Link to comment Share on other sites More sharing options...
kevinmi Posted August 1, 2010 Share Posted August 1, 2010 What tubes are you running on the Shanling now? The bugle boys?Mike, I'm running 1959 thru 1961 vintage Western Electric 396a tubes in the Shanling. I have some JAN tubes as well, but they seem a bit harsh. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted August 1, 2010 Share Posted August 1, 2010 Sweet project, and it's nice that you built it from scratch. Very nice work, I love the wood face. Dave. Quote Link to comment Share on other sites More sharing options...
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