Just to put closure on this...longer cable was the answer. I tried everything from 1' to 20'. Everything below 8' would not be seen by the DAC, irrespective of quality. In fact, an ancient very thin RadioShack 20'er seems to work as well as my nice 12'. Most were not specifically intended for 75 ohm use, I suspect. BTW, the Rega has a 2 prong power plug so I believe a ground loop is not an issue. And Al is right, the Rega is not, itself, worth spending a lot to correct. It actually sounds fairly nice, now that I can get sound...:8)
Truly weird Rega transport issue.
I recently purchased a used PEACHTREE DAC-IT (S/N 107010). My first DAC. It brought a truly weird phenomenon to light.
Using my Rega Planet as a transport (digital coax out) it will not recognize a signal when the cable is shorter than a couple meters.
Yep, you read that right...I've tried about a dozen different coax cables (MIT, BlueJeans, Acoustic Research), both traditional audio (unbalanced) and a 12" Blue Jeans purchased especially for it (a BJ Belden 1694A digital cable - 1 foot). Nothing. I double checked the output connector, seemed fine with no intermittents when I jiggled it.
My NAD CD player, on the other hand, does just fine from it's digital out to the DAC, at any length.
On the other hand, I just happened to have bought a 12' long sub cable (Blue Jeans LC-1) the other day and that works fine. Longer is better?
My first assumption was that the cables I was trying were older except for the sub cable,BJ LC-1. Nope. Found an ancient, super cheap 15' Acoustic Resarech that worked fine, too.
Thinking it might be an issue of digital cable design versus analog optimized cable, I purchased a 1 foot BJ digital cable...nope, didn't work.
Now it gets really weird. I hooked up a splitter on the digital out of the Rega, ran my new digital cable to the DAC (no sound) and then hooked the 12' sub cable to the other output on the splitter but left the other end of that cable unterminated. Got sound.
So, is there someone who can suggest what might be going on? Even better, how to fix it?
Thanks, Dan (AKA dancub)
Using my Rega Planet as a transport (digital coax out) it will not recognize a signal when the cable is shorter than a couple meters.
Yep, you read that right...I've tried about a dozen different coax cables (MIT, BlueJeans, Acoustic Research), both traditional audio (unbalanced) and a 12" Blue Jeans purchased especially for it (a BJ Belden 1694A digital cable - 1 foot). Nothing. I double checked the output connector, seemed fine with no intermittents when I jiggled it.
My NAD CD player, on the other hand, does just fine from it's digital out to the DAC, at any length.
On the other hand, I just happened to have bought a 12' long sub cable (Blue Jeans LC-1) the other day and that works fine. Longer is better?
My first assumption was that the cables I was trying were older except for the sub cable,BJ LC-1. Nope. Found an ancient, super cheap 15' Acoustic Resarech that worked fine, too.
Thinking it might be an issue of digital cable design versus analog optimized cable, I purchased a 1 foot BJ digital cable...nope, didn't work.
Now it gets really weird. I hooked up a splitter on the digital out of the Rega, ran my new digital cable to the DAC (no sound) and then hooked the 12' sub cable to the other output on the splitter but left the other end of that cable unterminated. Got sound.
So, is there someone who can suggest what might be going on? Even better, how to fix it?
Thanks, Dan (AKA dancub)
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Sounds like the waveform being supplied by the digital output stage of the Planet is distorted or messed up in some way, possibly as a result of its impedance being severely mismatched relative to the 75 ohm standard. That could conceivably be the result of either a defect in the particular unit or flawed design. In principle that could probably be addressed, and sonics improved, by purchasing a reclocker device and inserting it between the Planet and the DAC, using a long cable between the Planet and the reclocker if necessary. But considering the age of the Planet (it appears to have been introduced in 1998) and its relatively modest cost, it would probably be cheaper, simpler, and sonically better to just replace it with a new transport. Before doing that, however, I would suggest trying two things: 1)Try another cable that is specifically intended for 75 ohm digital applications. It sounds like you have may have just tried one such cable so far. Preferably try one that is about 1.5 meters (about 5 feet) in length. See this paper for further explanation. 2)Try temporarily putting a 3-prong to 2-prong adapter on the power plug of the Planet, so that the safety ground pin of the power plug is not connected to the outlet or its cover plate screw. The purpose of doing that would be to rule out the possibility that a ground loop issue involving the Planet may be causing or contributing to the problem. Regards, -- Al |
