Hi all,
My transport currently uses an RCA output. Is there audible benefit in replacing this with a BNC connector and doing the same on the DAC?
I have bought Belden 1505A (could not get 1506A) (RG59, 75 ohm) to make some DIY digital cable. Is it critical that the BNC's are 75 ohm or can they be 50 ohm. Again refering to sonics of course.
Anyone?
Thanks,
Ryan
My transport currently uses an RCA output. Is there audible benefit in replacing this with a BNC connector and doing the same on the DAC?
I have bought Belden 1505A (could not get 1506A) (RG59, 75 ohm) to make some DIY digital cable. Is it critical that the BNC's are 75 ohm or can they be 50 ohm. Again refering to sonics of course.
Anyone?
Thanks,
Ryan
Yes, it should help, and yes, the impedance is critical. A big question is did the manufacturer of your equipment make any effort to maintain 75R impedance inside the chassis.
Practically speaking, you can't, because you need a TDR. However you can check for really stupid things like not using 75R cabling internally, bad terminations, etc. Fixing those kinds of mistakes should help.
If you have a fast scope you can do some snooping by placing a BNC T in the transmission line and look for ringing or other problems.
If you have a fast scope you can do some snooping by placing a BNC T in the transmission line and look for ringing or other problems.
Thanks again. I have access to only a 20MHz scope. So looks like I'll be shotting in the dark... Suck it and see I guess? Have you tried Elso's improved SPDIF output and is it worthwhile-if it is, in what regards?
I use Harry's output stage. I've never tried Elso's.
I did not like his receiver buffer but I understand that some people do.
I did not like his receiver buffer but I understand that some people do.
------------------------------------------Dr.H said:
It's probably still worthwhile looking on your acope to see that catastrophic problems are not there. Guido Tent's XO3 prvides an excellent spdif output as well as a new clock.
Anything that reduces reflections will help, but if the interface is flawed, and most are, you may not hear the difference between 50 and 75 ohm connectors.
One thing to try.......drive your 'scope with the SPDIF output with no load. Then add a 75 ohm load. Accurately determine how much the level drops. It should drop by exactly 1/2. If not, you can determine the output Z by calculating the error.
Or.......put a 100 ohm pot on the 'scopes input to ground. Tweak it until it drops by exactly 1/2.
That is a staring point.........we'll go on from there.
Jocko.....Signoro TDR.
One thing to try.......drive your 'scope with the SPDIF output with no load. Then add a 75 ohm load. Accurately determine how much the level drops. It should drop by exactly 1/2. If not, you can determine the output Z by calculating the error.
Or.......put a 100 ohm pot on the 'scopes input to ground. Tweak it until it drops by exactly 1/2.
That is a staring point.........we'll go on from there.
Jocko.....Signoro TDR.
Thanks for all the replies.
Has Harry's or Guido's SPDIF output been posted anywhere so that I can build it as well?
Has Harry's or Guido's SPDIF output been posted anywhere so that I can build it as well?
Jocko Homo said:
How about using a bi-directional coupler to measure the reflected power?
We have 50 ohms ones at work but I never opened one to see what's inside. How do you build a 75 ohms one?
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