 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
98.156.120.233
At the end of Summer 2020, I took advantage of a sale price and a 60 day trial period to buy a Morrow Audio DIG1 cable. The cable is of minimalist design with no shield and I was skeptical when I actually saw it. It didn't take long before I was convinced that it was better than the Blue Jeans digital cable I had used for more than 4 years. The DIG1 outperformed in every way but one.
The change of seasons has dictated that we use the furnace to heat our house. Almost immediately after the thermostat relays click and send a message to turn on to the furnace, there's a brief sound dropout. When the thermostat clicks again, the steel rod is withdrawn, and the furnace begins its shutdown, the audio lessens in volume momentarily. The heating and cooling technician that inspected our heating system explained to me that when the thermostat sends its signal, a steel rood drops down to the burner unit to serve as a ground path. When the temperature reaches its desired setting, the steel rod is withdrawn after a signal from the thermostat. I know that I'm not a heating and cooling guy so I may have misinterpreted the explanation.
I didn't have that kind of problem when using the BJ digital cable or after the DIG1 was inserted during A/C season. The most logical thing I can attribute to the reason for the glitches is that the moment of establishing and removing the ground path for the burner is that a large pulse of interference is created. That burst or pulse is strong enough to be picked up by the DIG1 which acts as antenna for that very brief moment. At least that's my best conclusion so far.
While the easiest resolution to this problem is for me to open up my wallet again and grab the Visa card to use it for buying a shielded cable. Before I do that, I'd like to try finding a solution that would enable me to use the Morrow cable without the glitches. Does anyone here have suggestions?
Follow Ups:
Hi Postal Grunt, I found no description of the geometry involved with the DIG1 cable, either on the website nor anywhere else including any mention of the cable being unshielded. Perhaps the DIG1 is of the few S/PDIF digital cables that is not a 75 ohm coaxial cable, which by design features a braided shield for the return path, and by its nature shields the signal transmitted by the center conductor from noise. If the cable is a twisted pair or braided design that provides minimal shielding from noise for a sensitive unbalanced digital signal, the design itself could be the cause. Without knowing what type of geometry is in question, it is not predictable as to what is actually happening.
The following is taken from literature that Morrow included in the packaging of my cable,"Each strand of wire is individually insulated from one another and held together with cotton weaving. This is then covered with the outer nylon mesh that you see on the outside of the cable"
As I understand their approach, each of the conductors are wrapped by an unbleached cotton thread before the conductors are bundled together with the above mentioned cotton weaving. I haven't found any mention of geometry in their literature or online forums. When I hold the cable between two fingers, I feel only one small bundle inside the nylon mesh sheath.
After a quick survey of other online forums, I haven't found any posts describing a similar problem.
Have you asked Morrow about the shielding issue, Postal Grunt?
I've deleted my correspondence with Morrow but I do recall that I did ask about shielding and Morrow said that it chooses to not utilize any shields on their digital cables.
I too am skeptical that the lack of shielding is responsible for the dropouts. Do you still have the Blue Jeans cable? If so, have you gone back to it just to confirm that the problem is truly with the cable?
Yes, I have used the Blue Jeans cable since my purchase of the Morrow. It didn't have the same problem before my purchase or after. The Morrow didn't have any problems when I was running the AC. The problem only occurs at the beginning and end of the heating cycle, when a steel rod descends to act as a ground for the burner ignition or withdraws from the burner assembly to stop the cycle. My guess is that there's a pulse of EMI that's creating the problem. I could be wrong.
Not an audio solution, but how often is your heater turning on and off? Its should not be short-cycling.
"Writing about music is like dancing about architecture." ― Thelonious Sphere Monk
Cpwill
The heating system uses a York furnace and the thermostat is a programmable Honeywell model. The thermostat is mounted on a wall opposite the doorway to the room where my system is set up. The length of the cycles are, of course, dependent on the interior temperature of my house. I don't think that they're too brief or frequent. The whole AC/Heating unit was installed about 25 years ago, is maintained regularly, and has been reliable in my estimation.
Try contacting Morrow. I read elsewhere they took in trade one of their unshielded cables for a shielded one. I would start by describing your situation first though. They might have some other ideas.
There is DIY shielding with foil tape or braid. But it can get quite messy. Google will offer up some methods if you do a search.
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
I've already contacted Morrow Audio and they've been quite responsive, sending me another cable but that didn't do the trick. I can't fault them because the cable is otherwise much better than the previously used cable.
Great to hear Morrow sent another cable. Sorry it didn't make any difference.
I once had a dac that I replaced the supplied wall wart with a DIY power supply. Every time our convection oven fan would kick in, the dac would cut out like yours. I happened to have an old DIY power bar with a Corcom EMI filter in it. (Left over from the 70's for use with clunky and power sensitive computers.) Plugged into that and the problem went away.
So an EMI filter might work, but it could be quite a rabbit hole you go into as to where you put it vs getting a different cable.
May be simpler (cheaper) to experiment with ferrite rings on the digital cable or on some of the AC power cords you are using in your setup. I mention the latter because you want to eliminate as much noise as possible in the proximity of your unshielded cable.
Your system profile shows you have some special AC equipment. Not sure if you already have some filtered options there to try?
Cheers and good luck!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
I have to admit I'm skeptical the issue is cable related.
I had a very similar issue a few years back except in my case it was a heat pump kicking on and off. I spent a fair amount of money between the AC repairman and power conditioners before I found out that it was my preamp. Old, failing capacitors turned out to be the culprit.
Not sure how you'd go about narrowing the cause down to its root though without a trip to the repair shop if it is somewhere in the playback chain.
Do you have another cable you can put in to test your theory?
I had been using a Blue Jeans Cable that utilizes Belden 1694 for about four years or so and didn't have the problem I described. That time span includes using a Rotel receiver and presently, a Peachtree Nova 150. Other than the glitches, the Morrow substantially outperforms the BJC.
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
