Hi
I have a CD player - Teac VRDS 10 with a digital coax output - impedance = 75 ohm.
Then I want to connected it to a pro gear Behringer DCX2496 that has an input impedance = 110 ohm
Could that be a problem - I use a 75 ohm cable ?
Should it be terminated and how ?
I have a CD player - Teac VRDS 10 with a digital coax output - impedance = 75 ohm.
Then I want to connected it to a pro gear Behringer DCX2496 that has an input impedance = 110 ohm
Could that be a problem - I use a 75 ohm cable ?
Should it be terminated and how ?
Seems you have consumer S/PDIF 75 Ohm and the Behringer input you refer to is AES/EBU 110 Ohm. They do not mix AFAIK. The unit also has S/PDIF in but optical. Maybe that's an option from your TEAC?
...but if I'm not completely lost you may be able to get help from Guido Tent here on the forum...
The consumer signal is much weaker, that's that big problem and if you have short cables the impedance difference isn't a major problem (reflexions).
Why don't you test? If it works, it works, very "digital".
Why don't you test? If it works, it works, very "digital".
I have try it and it works but the DCX2496 has a level indicator that very offen goes up in the red so I thougth there could be something wrong - Termination ???
dkxdn said:
Hi,
Termination will attenuate the signal even further. You'll need to actually convert from SPDIF to AES. This may help:
http://www.epanorama.net/links/audiodigital.html#spdif
regards
Oh, brother.......
You don't want to get me started on this, P-A.
Will it work?
Yes.
Will it sound good?
Depends on your expectations.
Jocko
You don't want to get me started on this, P-A.
Will it work?
Yes.
Will it sound good?
Depends on your expectations.
Jocko
The normal signal level from a consumer signal is much lower than a professional.dkxdn said:
1 Vpp vs several volts.
As Jocko says, if you are satisfied, don't do anything. It sounds like crap => get a converter (transformer).
Not hindered by any Knowledge (as my Father said)
Sorry Per-Anders,
But I get the giggles from your post. The cable termination issue is explained in Horowitz page 879 a.f. in my edition: Transmission Lines, Chapter 13.09, stating that a transmission line should be properly terminated at both ends.
Looking forward to your 3000th post. I really envy you.
This forum should have a box obligatory to have checked before posting "Have you searched Horowitz?" instead of "have you searched?" for technical issues.
Postscript: I am a bloody chemist but you are an EE. To my ears your post sounds like pouring water into concentrated sulfuric acid or trying to extinguish a petrol fire with water.
Warning don't try to repeat these silly experiments!!!
peranders said:
Sorry Per-Anders,
But I get the giggles from your post. The cable termination issue is explained in Horowitz page 879 a.f. in my edition: Transmission Lines, Chapter 13.09, stating that a transmission line should be properly terminated at both ends.
Looking forward to your 3000th post. I really envy you.
This forum should have a box obligatory to have checked before posting "Have you searched Horowitz?" instead of "have you searched?" for technical issues.
Postscript: I am a bloody chemist but you are an EE. To my ears your post sounds like pouring water into concentrated sulfuric acid or trying to extinguish a petrol fire with water.
Warning don't try to repeat these silly experiments!!!
I say that digital signal are the same as for instance analog video signals. If you have reflexions which don't are near the logic threshold, the problems aren't huge. Some ringing or extra steps (due to reflexions) won't be a big problem.
I think we should ask dkxdn what he thinks about the sound coming out of his box. Does it sound horrible or does it sound nice? If he thinks it sounds not too bad I'll guess the problem isn't so big after all. But it gets more important the longer the cable is. In this case we have only missmatch in one end of the cable.
I think we should ask dkxdn what he thinks about the sound coming out of his box. Does it sound horrible or does it sound nice? If he thinks it sounds not too bad I'll guess the problem isn't so big after all. But it gets more important the longer the cable is. In this case we have only missmatch in one end of the cable.
Whatever, Per........
Maybe he doesn't know what jitter sounds like.
Maybe his D/A box has so much that a little more won't hurt.
I doubt it, though.
Jocko
Maybe he doesn't know what jitter sounds like.
Maybe his D/A box has so much that a little more won't hurt.
I doubt it, though.
Jocko
Re: Re: Whatever, Per........
Yup, Jocko has been saying this for a looong time.
Eric.
Hi peranders,peranders said:
Yup, Jocko has been saying this for a looong time.
Eric.
Which indicator goes into red ?.dkxdn said:
There are input gains that may be set too high.
Eric.
Reflecting on reflections
"Are you saying that a mismatch introduces jitter?"
I believe he might be......... I believe that it does and that seems to be why so much attention is paid to this issue. In addition to jitter increased reflections introduce RFI and high frequency garbage that gets into the analog sections of the DAC and following analog stages of the system. Short digital cables sound bad. They provide a low propagation delay which puts the primary reflection even closer to the logic transition point. I think you might benefit from reading some from the www.sigcon.com website and the book:
High-Speed Digital Design: A Handbook of Black Magic by Howard Johnson
Do some searches on this forum because this subject has been thoroughly discussed.
What happened to the good natured PA that was always telling me to relax?
"Are you saying that a mismatch introduces jitter?"
I believe he might be......... I believe that it does and that seems to be why so much attention is paid to this issue. In addition to jitter increased reflections introduce RFI and high frequency garbage that gets into the analog sections of the DAC and following analog stages of the system. Short digital cables sound bad. They provide a low propagation delay which puts the primary reflection even closer to the logic transition point. I think you might benefit from reading some from the www.sigcon.com website and the book:
High-Speed Digital Design: A Handbook of Black Magic by Howard Johnson
Do some searches on this forum because this subject has been thoroughly discussed.
What happened to the good natured PA that was always telling me to relax?
Attachments
Re: Re: Re: Whatever, Per........
Oki, doki, but can anyone present any numbers? How much jitter do you get, just because of the mismatch?mrfeedback said:
When I mean mismatch I mean so little that any reflexions won't be lower than the transistion points for logic. I'm not _that_ dumb. The assumption is that the main flank is triggering the logic.
Also duty cucle within reasonable values is not either any important, or?
Also duty cucle within reasonable values is not either any important, or?
I think we can make this conclusion:dkxdn said:
75 ohms out + 110 ohms cable(or do you have a 75 ohms?) + XLR-contact + 110 ohms input => sounds quite alright but you get a red light. Have you checked in the manual when this light is suppose to be lit? I suspect a weak signal because consumer signal is much weaker than a professional.
If it sounds great, why bother further? You could test to have the right connections and see if it makes any difference.
75 ohms out <-> 75 ohms cable <-> transformer 75 unbal -110 bal <-> 110 ohms cable <-> 110 ohms input.
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