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Valve CD player

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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.



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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.



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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.

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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.



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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.

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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?

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