IPB

Welcome Guest ( Log In | Register )

Coaxial SPDIF cable?
bennetng
post Nov 25 2012, 15:19
Post #1





Group: Members
Posts: 224
Joined: 22-December 05
Member No.: 26587



We were told only use 75 ohm cable for SPDIF purpose. So what is the impedance of typical analog RCA audio cable?

Another question is I have a 75 ohm TV antenna cable, is it suitable for SPDIF purpose?

Some people said that wrong impedance may not cause problem if the cable is short enough, if it is true, then what cable length will cause problem?

I ask these because I just made a SPDIF cable with two spare RCA plugs and a 75 ohm TV antenna cable (3 feet), I tested it using RMAA and found no problem (+- 0dB freq. response, -146dB noise level, 0% THD and so on) and I can't hear any problem as well. Does it mean that I don't need to spend money to buy a standard cable?

Thanks.
Go to the top of the page
+Quote Post
 
Start new topic
Replies
greynol
post Nov 25 2012, 19:08
Post #2





Group: Super Moderator
Posts: 10000
Joined: 1-April 04
From: San Francisco
Member No.: 13167



Are you sure your speakers aren't being fed by a TTL signal?


--------------------
Placebophiles: put up or shut up!
Go to the top of the page
+Quote Post
washu
post Nov 26 2012, 03:28
Post #3





Group: Members
Posts: 135
Joined: 16-February 03
From: Ottawa
Member No.: 5032



QUOTE (greynol @ Nov 25 2012, 13:08) *
Are you sure your speakers aren't being fed by a TTL signal?

I'm not sure what you mean by a "TTL signal" in this context, but they are definitely being fed by SPDIF.

The signal path is as follows:
HTPC Toslink out -> standard Toslink cable -> Marantz 6200 Toslink In -> Marantz 6200 SPDIF out -> long non-spec SPDIF connection and adapters -> Cambridge Soundworks speakers.

This allows the same music to be played on the speakers connected to the Marantz 6200 and the Cambridge Soundworks simultaneously. This only works for PCM signals, not AC3 or DTS, but that is a limitation of the Cambridge Soundworks speakers. The Marantz 6200 does not output anything on the analog outs when fed a Toslink or SPDIF signal.

I actually have a third and forth sets of speakers connected to another receiver that is fed from the Toslink out of the Marantz. That is over a 60 foot optical run which also works fine. A rather hackish full house sound system, but works great.
Go to the top of the page
+Quote Post

Posts in this topic
- bennetng   Coaxial SPDIF cable?   Nov 25 2012, 15:19
- - Speedskater   a] The longer the cable the more important the 75 ...   Nov 25 2012, 17:41
|- - greynol   QUOTE (Speedskater @ Nov 25 2012, 08:41) ...   Nov 25 2012, 18:27
||- - Arnold B. Krueger   QUOTE (greynol @ Nov 25 2012, 12:27) QUOT...   Nov 26 2012, 02:53
||- - Soap   QUOTE (Arnold B. Krueger @ Nov 25 2012, 20...   Nov 26 2012, 03:00
||- - Arnold B. Krueger   QUOTE (Soap @ Nov 25 2012, 21:00) QUOTE (...   Nov 26 2012, 14:31
||- - Soap   FWIW the fraction of my interior wiring done by th...   Nov 26 2012, 14:37
|- - Soap   QUOTE (Speedskater @ Nov 25 2012, 11:41) ...   Nov 25 2012, 18:36
- - pdq   Analog audio cables may not be closely matched to ...   Nov 25 2012, 18:00
- - mzil   Besides the wire itself, the plug used on the end ...   Nov 25 2012, 18:14
|- - pdq   QUOTE (mzil @ Nov 25 2012, 12:14) F-pin a...   Nov 25 2012, 21:52
|- - mzil   Both exist: http://en.wikipedia.org/wiki/BNC_conn...   Nov 25 2012, 22:49
|- - bennetng   QUOTE RG6 and RG59 look the same in photos, but RG...   Nov 26 2012, 03:51
||- - mzil   Your cable is marked with a JIS (Japanese Industri...   Nov 26 2012, 05:40
|- - 2Bdecided   QUOTE (mzil @ Nov 25 2012, 21:49) Both ex...   Nov 26 2012, 13:52
- - Glenn Gundlach   QUOTE (bennetng @ Nov 25 2012, 06:19) We ...   Nov 25 2012, 18:17
- - bennetng   Thanks all. Although I don't have enough knowl...   Nov 25 2012, 18:45
- - washu   I've found SPDIF rather resilient when run ove...   Nov 25 2012, 19:03
|- - Arnold B. Krueger   QUOTE (washu @ Nov 25 2012, 13:03) I...   Nov 26 2012, 03:01
- - greynol   Are you sure your speakers aren't being fed by...   Nov 25 2012, 19:08
|- - washu   QUOTE (greynol @ Nov 25 2012, 13:08) Are ...   Nov 26 2012, 03:28
- - bennetng   Thanks mzil!   Nov 26 2012, 08:56
- - Dynamic   You should get away with a lot with S/PDIF because...   Nov 26 2012, 20:39


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 29th July 2014 - 03:50