vmps, art d/io, & boldercables.com

Hi Doug,
It is generating interference with my radio reception. Not unusual for digital products to do this (I've tried expensive ones that were worse in this regard), but it is annoying. Have to disconnect interconnects to it in order to listen to tuner w/o static. Was hoping that maybe the modifications do away with this and will investigate as you suggest. Still burning it in (it does improve each day) and waiting for the upgraded power supply (Stancor 3400mv) to arrive. Other things I've noticed is that it sounds best in the x2 mode; can't get any sound in ext sinc mode. Also, mine sounds a little better with the tube installed. I know the tube supposedly has nothing to do with the d/a circuit, but I notice the led's next to the tube warmth adjustment don't work unless the tube is installed and the sound is slightly smoother and there is less of the RFI mentioned above when the tube is installed. I won't comment on the sound until I have gotten the upgraded ps and it has run for a couple of hundred hours.

joe, you're correct that the tube warmth adjustment led's don't work w/o the tube. but, as the tube is in the adc circuit, these lights are meaningless when used as a dac only... folks have thought a possible reason why the unit may sound better w/the tube, is that it draws power away from the diodes in the adc circuit, & these, being crap, may let some unwanted signals feed back into the dac side. one of the recommended mods is replacing *all* the diodes, both dac & adc, w/schottky's, which work much better... could be part of the rfi problem you're experiencing. i'd suggest moving the dac, & the cd-player in relation to the tuna, to see if this has any effects. also, may want to put ferrite magnets on the power cords & interconnects. also, are you using any gain attenuation? the di/o, being a pro-audio product, outputs a 7v signal, while 2v is more typical of home-audio gear... i recall you mentioning using an attenuator module, mebbe this also has something to do w/the rfi...

re: getting it to sync properly, it seems to be very sensitive to the digital cabling; believe it or not, i have had great success w/the $10 rat-shack 75 ohm cable. no sync problems at all w/my nad changer. but, i'm gonna try an apogee wyde-eye pro cable. (~$25 street-price) brianw sez it's the best, short of dropping $1200 on an fim digital cable... also, the digital input resistor is 100 ohms (pro audio, again?); i replaced it w/a 75 ohm resistor. you really need to do a few tweaks to the di/o, along w/hooking up that stancor. the thing, quite good stock, really responds to these simple mods.

doug s.

Thanks for all of your advice, Doug.
I think you're right about the tube. The sound became subtly more refined and relaxed with the tube in vs without so I am leaving it in for now. I just got the Stancor ps tonite and that makes a much more noticeable improvement.
I have ferrite RFI blockers on my Ic's but will get some more for the rest of the system.
I tried going w/o the line attenuators and it did not work out. Some aspects of the sound improved, like the size of the soundstage, but the sound got a bit ragged as I could hear my input stage starting to overload on dynanmic passages-not pleasant to hear. The Stancor power supply plus burn in time has improved the soundstaging.
I have tried the Radio Shack digital cable years ago and found it was very simiar to Canare Digiflex cable; not bad, certainly worth $10.
The Apogee is only a little better. I have owned both the old and newer version of the Apogee Wyde-eye. I am currently using Harmonic Tech Copper link, which I prefer to the Apogee. I have tried Monster data link and Ensemble Digiflux with the Art DI/O and I also have a Madrigal MDC on hand (which costs more than the DIO), but until the unit burns in, I think I will go with the Harmonic Tech for now. The Stancor ps has warmed everything up a bit, so I will try all of the above mentioned cables again in a few days and will see what I can do to get rid of the RFI.

JoeB: You're leaving the tube in for D/A? The tube is for A/D only, and will just draw from the power supply. This isn't a good thing.

Doug: BTW, Thank you. I bought the Apogee cable from fullcompass.com. I'm very happy with it's full freq. extention, it's ability to resolve low level information, and found it to be a very dynamic cable (both micro and macro). I'm sure that the FIM cable is better, one of my friends has their speaker cables and interconnects. However, at less than $30, the Apogee is a steal! It smoked the Monster cable that I'd paid around 3 times as much for.

steve, there seems to be a trade-off w/the toob in the circuit - you're correct that it draws power from the p/s, but it also reduces elec'l leakage (i'm sure this isn't the correct technical term!) from the adc side into the dac. best bet is to try for yourself.. some prefer it one way, some the other. if a di/o's only mod is the upgraded p/s, & internal parts haven't been replaced, i'd be inclined to leave the tube in. if lotsa mods have been done, yank the tube...

doug s.