Quote:
Originally Posted by Radio Wrangler
Ah, I had an Acos Rega with lustre arm for many years. My brother still has it. It was fully satisfactory.
Toslink £9k !
MM, you should now be regretting getting a cheaper one. If you had one of the £9k jobs, just think of the data coming out of the optical modules... the scintillating pinpoint 1's, the deep, velvety 0's. And as for the reassembled music, the adjectives you would have to deploy would strain anyone's vocabulary.
David
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Of course absolutely nothing you do with a TOSlink cable will compensate for the risible bandwidth of the transmitter and receiver modules. The main manufacturer is Toshiba (not surprisingly!) and the maximum specified bandwidth is 10MHz (the regular ones have a bandwidth of 500kHz!), with a pulse width distortion of +/-55ns for the 10MHz ones.
Absolutely nothing you can do with the bit of optical string that connects a TOSlink transmitter and receiver will compensate for the shortcomings of those modules. And that is before you factor in that the LED in the transmitter has a finite life, with the optical power reducing over time. Of course most audio nuts leave their gear on all the time, practically guaranteeing that the whole link will be below par.
The whole rationale between this optical link was back in the days of red-book 16bit 44.1kHz audio.
The joke used to be that TOSlink meant that you TOSSed the cable in the waste bin, or that only Tossers would use one. Having said that, I use TOSlink cables (cheapo ones) from each TV - but largely because that is practically the only way of getting an audio output from the things now.
The only real advantage is electrical isolation of this link.
You can do a whole lot better with coax with pulse transformers at send and receive to give galvanic isolation. Of course the devil is in the detail, because so called audio pulse transformers do not like working at 75 ohm send and receive impedances. But you can match them very nicely using resistive pads. It is pretty straightforward to get clean rise and fall of ~3.5ns.
Whether optical or coax in this context uses SPDIF (Sony Philips Digital Interface Format) signaling, which is in itself a historical peculiarity from the early days of red-book CD in the early/mid '80s.
Craig