Working coax cable?

Grey

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Joined
Feb 6, 2024
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Does anyone know of a 75ohm digital coax cable that fits/works with Pro Plus? I’ve tried two that work with other devices and my dac, but neither works with the WIIM. The stereo analog cable that came with the WIIM works on Coax out (if I just use one of the leads), but I need to use that cable for the line output. I don’t want to buy multiple cables just to find one that works so any help is much appreciated.
 
I posted on my experience with this quite some time ago, for coax from a pro to my dac.
Summary:
Using a really cheap 'analog' interconnect, the sound was ok.
Using a diferent (quite expensive, but hey, cost isn't everything!) analog interconnect sounded much better.
Using a (quite expensive too) digital interconnect sounded no different to 2nd analog interconnect.

So, if you happen to have a few different analog interconnects lying around, try each of them for a few days at a time.
Will do - good idea.
Thanks
 
Problem solved.
I tried a different dac and all cables work. It seems that the coax output from the Pro Plus is too weak in combination with the 75 ohm cables to drive the original dac. Onlyoneme had it right. I guess I’ll have to use a regular 50 ohm analog cable.
Thanks, everybody.
What dac didnt function with the 75 Ohm cable ?
 
D50s is known for issues over coax with some streamers including WiiM. Some people implemented succesfully small HW changes inside the DAC to fix it.
I've heard that, but I can't remember where. I don't know if I'm up to the task, but I'd appreciate any detailed info or a URL to find out more.
 
I posted on my experience with this quite some time ago, for coax from a pro to my dac.
Summary:
Using a really cheap 'analog' interconnect, the sound was ok.
Using a diferent (quite expensive, but hey, cost isn't everything!) analog interconnect sounded much better.
Using a (quite expensive too) digital interconnect sounded no different to 2nd analog interconnect.

So, if you happen to have a few different analog interconnects lying around, try each of them for a few days at a time.
Can you expand on what you mean by 'better' in this context?

How does changing a cable alter the signal ? I was under the impression that it either works or it doesn't. What am I missing?
 
How does changing a cable alter the signal ? I was under the impression that it either works or it doesn't. What am I missing?
You are absolutely right (in my opinion). Digital is digital: It works when it works. You cannot improve or worsen the signal with any cables. This is the advantage of digital transmission as opposed to analog RCA signals.
 
Can you expand on what you mean by 'better' in this context?

How does changing a cable alter the signal ? I was under the impression that it either works or it doesn't. What am I missing?
Note that I only experienced a change from using a really cheap analog cable.
Maybe it was poorly shielded and carried a lot of noise through to the dac.
Maybe it wasn't quite as good at keeping the digital eye pattern open.
Whatever it was, it sounded duller, muffled, flat, less enjoyable. No fancy analogies here, essentially just 'worse'.
Yes, I might even say that using a different cable was like lifting a curtain... (you know who I'm teasing here!).

I can only say that it was a very obvious difference, similar to the difference between using the pro's dac and analog out (with the same 'decent' analog interconnects) to my amp vs pro's digital out to my dac/amp. The former was, again, significantly worse.

Generally I'm with you - if the sender can send the pulses correctly, the cable can transmit the signal with minimal degradation and the receiver can clock it correctly (and half the point of a "digital" signal is that it is much more tolerant of degradation), how can it make a difference?
I'm mostly assuming noise, hence things like galvanic isolation on dac inputs.
 
Well, after a great deal of trial and error, I’ve found that the most stable coax connection from the ProPlus to my Topping D50S is using one lead of the RCA analog cable that came with the ProPlus.
i’ve contacted WIIM twice to ask if I could buy another one of these cables but have received no response.
Does anyone have any idea how I can get a response from WIIM on this?
 
Well, after a great deal of trial and error, I’ve found that the most stable coax connection from the ProPlus to my Topping D50S is using one lead of the RCA analog cable that came with the ProPlus.
i’ve contacted WIIM twice to ask if I could buy another one of these cables but have received no response.
Does anyone have any idea how I can get a response from WIIM on this?
Maybe someone here, say someone who has got a replacement unit, can send you theirs if they don’t need it?
If so, can I ask that you DM each other rather than communicate here as these sorts of transactions are best done offline.

I’ll also escalate this to WiiM and see if I can elicit a response.
 
Thanks much, Brantome. Just a noob question - where do I post my email so that a member can DM me?
Those who want to offer theirs should use the click on your profile name on your comment and “start conversation” there. Those are direct messages between you and them.
 
Digital coax is specified to have a characteristic impedance of 75 ohms. That means Wiim's coax output and your DAC's coax input are terminated with 75 ohms. With matching impedance, there is no reflection bouncing back and forth. When reflection is randomly added or subtracted from the signal, depending on the magnitude of the reflection, a 0 maybe interpreted as 1 or vice versa.

Characteristic impedance is the square root of L/C. So there are many combinations. 10x the C together with 10x the L will give you the same characteristic impedance.

Delay/Ft is square root of (L/Ft)*(C/Ft). This is the time it takes for the signal to travel from one end of the cable to the other end. Also is the time it takes for reflection to bound from one end to the other. So larger LC will have longer delay. Longer cable length will have longer delay.
 
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