2. digital
  3. 1011511884

Someone should kick me in the keester

No matter how much I know and learn about audio, I can still be completely oblivious to some of the most basic things. Today I discovered a new dimension to that fact.

For quite a long time I've been complaining (privately) about the lack of detail, imaging, and overall clarity my system had, in spite of the quality of its components. I spent a bit of time swapping tubes, changing interconnects, and adjusting the speaker position without a great deal of success at cleaning up the sound or providing a solid soundstage to my satisfaction. While most of my friends couldn't hear the problems I described, I certainly did and it lead me to think that this might be as good as it gets.

A few weeks ago I decided to order some parts to build the Max Rochlin memorial digital cable, partly because I needed a project to keep me busy, and because it was the only cable in my system I had not yet replaced. I finally got around to building it this morning (for those that are thinking about trying it, it took me about an hour or so) and discovered after installing it that I had an entirely new audio system. The soundstage was right on the money and rock solid, the music was clean as a whistle (even through Moussorgsky's Pictures at an Exhibition), the bass tight, the midrange a thing of beauty, ... I could go on.

Anyway, it turns out that my suffering for the past year or so was due entirely to an inferior digital cable and nothing else. I had been very skeptical in the past about the differences a digital cable could make (bits is bits?), but I now stand both red faced and enlightened. I'm not entirely sure that I understand the physics behind the change I made, but it does seem that there are things about digital transmission that I need to brush up on.

Anyway, if confession is good for the soul, then let me be the first to give my spirit a lift :-).

For the record, the system is mostly CJ (17LS, Premier 12's, DA2-B DAC) with a Pioneer DVD as a transport.

-- Ken
kjg
sean
6,231 posts
 
Dekay, you have me REALLY confused. The way you described things, you have an interconnect that has a 60" center conductor with a 30" ground ??? If this is the case, either the center cable is coiled to equal the same distance as the other shorter cable or the cables do not run parallel to each other for their entire length. Either way, i would venture to say if either of those guesses is close, your cables are FAR from a nominal 75 ohm impedance.

The idea of different length conductors could help to "play games" with or "hide" standing wave based problems, but might also contribute to time smear.

Can you clarify what you were trying to describe to us ? Sean
>
dekay's avatar
dekay
5,385 posts
 
Sean: The long portion is looped around the short one in seven half knots which are approx. 3" in diameter. No metal RCA's either (this is the one made out of the 47 Labs OTA kit which is 26 gage solid core copper enclosed in extremely thick Teflon isulation along with plastic RCA's). The cable exibits less "smearing" (by a long shot) over any traditional cable that I have used in this application. It can also be tuned (to a certain extent) by the location/spacing and size of the loops (the larger the loops, within reason, the more open and realistic the sound, but too large and you loose imaging). It's an ugly sucker, but it sure sounds good. The Mapleshade cable (not as good, but still no sluff) is also not a 75 ohm design, but is quite unusual as well in its construction.
sean
6,231 posts
 
I'm pretty sure that i can picture what it looks like from your description. It sounds as if you've created some type of inductive load with non-symetrical loading between the polarities. Due to the "loops" or "knots", the hot side would see a greater percentage of this inductance. As to the rest of the cables, are they anchored together at any point or somewhat hanging loosely around each other ? The further that they are spread out from each other, the greater the inductance.

As such, it is possible that you've somehow created a "resonant trap" that is tuned close to the output frequency of the transport or a harmonic of it. Playing with the size and placement of the "loops" would alter the impedance, therefore changing the resonance or tuning of the circuit. The farther that you got away from the central beneficial frequency, the more the effect would "collapse". Keep in mind that this is strictly a guess at what's taking place.

One more question. Where in the world did you come up with this configuration ??? : ) Sean
>
praudio
39 posts
 
Ditto Dekay,my best digital cable is not a 75 ohm one; it is a rca-rca audio cable. And IMO most quality audio cable sound better than real digital 75 ohm one.
dekay's avatar
dekay
5,385 posts
 
Sean: It is a loose adaptation of a concept shared with me by Richard @ Vantage Audio. Their design (which I do not feel comfortable sharing) is of course much more refined than this "wing it" cable, but I really cannot thank Richard enough for his guidance on this project (I really enjoy his "out there" thinking). Oddly, I received an email which stated that other OTA user's had benefited by making the "Cold" lead a bit longer (just the opposite), but this did not pan out in my setup. Yes, I suspect that this is all system dependent and my intention was only to point out that one should not "limit" themselves when designing a cable. I don't feel that we really know enough about this "whole thing" to do so @ this stage in the game. Based on the EE comments that I have read @ AA the OTA cable should not function as it does, anyway, but it does in that it provides full frequency response from the LF's to the HF's (other 26 gage copper/Teflon cable that I have experimented with does not). Go figure. If three people were to "share" one of the kits @ $200 a pop, they would receive enough cable/RCA's to make up a single pair of 10' speaker cables and a set of 1.5 meter (or longer) analog IC's (each). I think that you would get a kick out of this product in one of your lower powered systems (don't know if I would want to pump 1000 watts through it though:-).
More to discover