True 75 ohm digital cable

[jimbones]

While I am waiting for my new optical cable to arrive i am using a "digital" SPDIF cable that someone gave me with my old M2Tech Hiface device. I don't even know who made it and am pretty sure it is not a true 75 ohm cable. Has anyone found there to be a difference when using a true 75 ohm cable vs other "digital" cables? My dac and cd player will occasionally fail to sync and I get that annoying clicking sound. The manufacturer recommends a true 75 ohm cable. I want to make sure I get a decent cable. Thanks.

[sleepyguy24]

Hi Jim

Do you need a true 75 Ohm cable? I can loan you a budget one that was made with Canare 75 Ohm Cable. If you need an AES/EBU XLR type of digital cable I have a pair of those as well from Belden. 1800F series cable. You can try these out and decide for yourself. Then when you are ready you can make the jump to the more expensive digital coax cables.

My favorite digital coax cables that are true 75 ohm cables are Black Cat Audio SilverStar that go for around $150 and McCormack Mod Squad Wonderlink J cables that used you can find for $60 to $95 depending on the seller.

A budget one that I used was this one previously.

http://www.bluejeanscable.com/store/digital-audio/index.htm?PHPSESSID=8c188c0317b738e490d719c29b8cab15

I did my A/B comparisons years ago between Toslink and digital coax and don't remember the exact results. From what I can remember I had an improvement in overall sound clarity but I was comparing Monoprice premium plastic toslink vs the Blue Jeans Belden 1694A digital coax cables.

[jimbones]

I would appreciate If you live on long island I could pick it up!!
Yea, Emotiva says that I should be using a 75 ohm cable (I use RCA), and that the cable I am using might be a problem. I doubt it but you never know with these things. 
Last night I was able to listen to cd's without any issue but the other day it was clicking away.

[mdconnelly]

I've had great success with the Black Cat Silverstar (formerly Veloce).   My understanding is that getting true 75ohm with RCA terminations is a big part of the problem.  Black Cat uses BNC connectors on the Silverstar and provides BNC-to-RCA adapters for those that require the RCA plugs (which, admittedly, most of us do).

The 1.23m Silverstar is $150 but they now offer a 24" Silverstar for only $99.

[StereoNut]

Jim

Do your player & DAC have BNC connections?  AFAIK, the way to get the best 75ohm connection is to use BNC's which are supposedly "native" 75ohm.

I'm using a Black Cat Veloce (BNC <> BNC) with great success.  The SilverStar in my system was overly clinical and too bright.

Just my 2¢

SN

[DaveC]

BNC was designed for the application but there are some 75 ohm RCA plugs like WBT's Nexgen, Canare and maybe DH Labs. In any case, DH Labs is reasonably priced and their cables are manufactured by Neotech so the quality is there too.

[jimbones]

yes I aaas reading about 75 ohm cables and apparently it is the rca connector that is the bottleneck.

[jimbones]

Thanks to Bill for lending me some spdif cables yesterday. Only did a quick spin with them but in a bag he lent me a lightspeed harmonic, Elco Liberty and monster digital cables. Some slight differences, need more assessment time. (BTW he also lent me a pair of QED speaker cables to compare against my MIT music hose 750) That was a bigger difference than the digital cables. more to come.

[sleepyguy24]

Uhh ohh. Be careful Jim. You just recovered from a bad case of audiophilia. Don't get burned out tweaking/system adjusting. It happened to a seasoned audio vet I met. He got so caught up with sonic differences with cable changes he lost the passion for music. Stopped doing everything music and audio wise for 3 years then SLOWLY got back into it. Now he is happy with his system as is and just selling records.

I even hit some burnout with tube rolling and cable swapping. I once had a small notebook with findings and lists of different tube/cable combinations. Played the same tracks over and over to evaluate and got sick of my favorite band. I just had to stop and leave things as is then made some adjustments when I found a problem.

[jimbones]

I'm good, I'm good. 

Audio is not as easy as it was 30 years ago when you went down to your local dealer to try something. Everything is a hard sell now. I take opportunities to try out some stuff for comparison. I am still not completed with my rebuild. If there isn't an improvement to be had, money will not be spent.

Uhh ohh. Be careful Jim. You just recovered from a bad case of audiophilia. Don't get burned out tweaking/system adjusting. It happened to a seasoned audio vet I met. He got so caught up with sonic differences with cable changes he lost the passion for music. Stopped doing everything music and audio wise for 3 years then SLOWLY got back into it. Now he is happy with his system as is and just selling records.

I even hit some burnout with tube rolling and cable swapping. I once had a small notebook with findings and lists of different tube/cable combinations. Played the same tracks over and over to evaluate and got sick of my favorite band. I just had to stop and leave things as is then made some adjustments when I found a problem.

[williewonka]

yes I aaas reading about 75 ohm cables and apparently it is the rca connector that is the bottleneck.

Jimbones - you are correct - the RCA connector is generally of a lower impedance, which causes distortions at the boundary resulting in dropouts or jitter.

Using an RCA with a higher impedance, like the KLE Innovations Harmony line of RCA's - or the 75ohm RCA's from Canare etc. as DaveC suggest will rectify that.

I have "The Name" from Van den Hul - sold as analogue IC's, but is recommended by VDH for use as a digital IC.

I tried the Copper Harmony from KLEI on those and it worked flawlessly.

Remember - a digital signal is just an analogue signal with very square corners

So even today's good analogue IC cable can often be used in place of 75ohm cable.

Regards

[tmazz]

Remember - a digital signal is just an analogue signal with very square corners

Yes, but you must also remember that as Dr Fourrier thought us, it is the addition of the upper harmonics that make the corners square, so in order to cleanly pass a digital signal you must have a transmission path (in our case a cable) that has a bandwidth of at least 8 - 10 times the bitrate of the digital signal you are planing to connect with it.

[williewonka]

Remember - a digital signal is just an analogue signal with very square corners

Yes, but you must also remember that as Dr Fourrier thought us, it is the addition of the upper harmonics that make the corners square, so in order to cleanly pass a digital signal you must have a transmission path (in our case a cable) that has a bandwidth of at least 8 - 10 times the bitrate of the digital signal you are planing to connect with it.

Tmazz - well - I didn't know the actual numbers (btw - thanks for that), but I was aware that throughput is a key issue for digital cables.

So perhaps you can provide some more enlightenment - is it the cable architecture of the 75 ohm cable (i.e. being coax) or the copper quality that makes it more suited to digital.

Thanks

[jimbones]

As I understand it, physical dimensions and construction are key.

[tmazz]

As I understand it, physical dimensions and construction are key.

I agree that the dimensions and construction are key to passing wider badwidths, but I think more important for our particular application is the fact that the transmitters and receivers in the SPDIF standard have a 75 ohm impedance and using a cable that matches that impedance minimized reflections occur when you have an impedance mismatch and the bit errors that ultimately result from those reflections. In general, the most efficient transfer of a signal across an interface will occur when the impedances on either side of that interface are equal. (which in part is why we have different taps on the output transformer of a tube amp.)