Art di/o question

[tmazz]

I recently picked up an Art di/o with the full Boulder Cable Mensa Mod treatment off of ebay. Great price, great sound, very happy with it. I have been running into a strange problem with it. It seems to be extremely sensitive to static discharge. In the past few weeks as the cold snap has rolled in the heat has bee running more and the static level in the room has gone up. Every time I touch anything but the powerline conditioner and draw a spark the di/o locks up and looses all audio output. I cannot get any sound out of it until I reboot the device by pulling out the A?C plug and restarting it. (Does the di/o run on Windows software?  ) this happens whether I touch the CD transport or the preamp (the two most likely suspects), so I figure the static must be traveling through the ground plane.

I pulled a room humidifier out of the garage to try and alleviate the static problem and found that the filter had dried out and was no good. Ordered a new one and it should arrive In the next couple of days. That should get rid of the static, but I an still curious about the problem. I have had audio equipment in this room for 25 years, including several other DACs and never had a problem like this before, even before we replaced the forced hot air heat with baseboards and had more static that we do now.

Are there any current or former di/o owners out there who have had similar experiences?

[richidoo]

I don't know about the static, but their old web domain is now porno, so be careful if you try to help Tom with this one...

My only idea is that signal ground is lifted from chassis in just the right places so that the shortest path is through the di/o. But it is probably on rubber feet, and has a wall wart with no true ground. Or maybe it just flakes when it sees the spike on the signal ground, even if current is not passing through it.

My diy DAC acts similarly,  but for good reason. Wood case, and volume control is not grounded to "chassis" (AC ground) The control processor is on the VC daughter board. It freezes at full throttle volume. A metal case would cure it, or bonding cable to ground in the PS.

Can you ground the di/o chassis more deliberately? Connect it to an AC outlet faceplate screw with a length of wire.

[mgalusha]

My recollection of these was they were sensitive to static with some transports, CAL Delta comes to mind. I'd do as Rich suggests and run a piece of wire from the chassis to something grounded. It need not be very large, 20 or 22 gauge would be fine.

[tmazz]

Good thinking. The Boulder upgraded power supply has a three prong AC plug, but the connection into the di/o itself is only 2 wire. I will have to open the power supply and see of the ground wire goes to the PS case or just floats and goes nowhere. If it does the the case I will bond the PS case to the DAC case. If not I will bond it to the preamp ground to try to avoid ground loops. I'll let you know what I find.

[tmazz]

Well, no good deed goes unpunished......

I took your advise and went to bond the di/o case to a hard ground and in doing so had to move the outboard power supply. When i did that all of a sudden the power supply output dropped to zero. Ouch.     Opened the power supply case and found that it contained only a toroidal transformer and a black cylindrical unmarked component that was (past tense) wired in series with the transformer output. This cylinder had at one point been hot glue down to prevent it from moving, but had come loose in shipping and the lead at one end had snapped of right even with the end of the cylinder. (it would have been too easy to break further up the pigtail so tat I had enough room to make a solder repair). The next morning I call the service folks at Boulder to ask what the cylinder was and how i could get a replacement. They informed me that since they did so many different mods they had no idea what it was, but if I sent it out to them they would give it a look. They thought it might be a Bybee Quantum filter, but could not be sure.

Not wanting to part with the unit for weeks, I started to do some reseach on my own. I looked at the Bybee web page and the cylinder did in fact look like one of the large Quantum filters.After looking up the physical and electrical specs on the Large QF, I did some measurements on the broken cylinder and determined to my satisfaction that it was in fact a Bybee. This was a good thing because other than filtering out noise the Bybee did not have an effect on the output voltags and current of the power supply and I could bypass it and temporarily wire the transformer output directly to the di/o power input so at least the DAC would be and running plug while I went out and got a new Bybee (which may take a while since like I said in another thread, with all of the changes that i made to my system over the past year, my toy money is kind of tapped out at the moment.)

Anyway, by the time I got everything rewired and back in the system it was too late to do any serious listening  (and still be able to get out of bed for work in the morning  ) So I just did a quick check to make sure everything was functioning as it should (it was  )and I will have to further evaluate both the sound without the Bybee and whether the ground bonding eliminated to di/o lockup problem. 

I'll let you know what I find.

[mgalusha]

I might have a single spare large Bybee. If I remember I'll look tonight. The price will be right if you're interested.

[tmazz]

Great, Let me know

[tmazz]

One other thing. The Bybee would have to be new or if not new at least with the same length pigtails as a new one. The way it needs to be positioned in the PS case the connection is soldered at the very end of the original pigtail. If they were trimmed for installation in another application they wont reach where my connections are going to have to be made.

Thanks,
Tom

[rollo]

Tom there is tweak rec co for the Bybee filter @ the tweakgeek site. They suggest wrapping thefilter with ERS paper slipping a copper tube oer and repeat the ERS. Cover with heatshrink for I believe they say a tenfold improvement.
   I am very curious to learn of your results with the filter in place when you get to it.


charles