Class D come of age - Coherent amplification

[Edward]

It could well be the imperfect unfold causing the issue, but an MQA file is still larger than a red book file I think. I also think they do eq it to make it sound slightly different, although with a proper unfold that should not sound 'bad'.

It was not bad as such, just that the Redbook version was 'nicer'. There was a passage in particular that Adam and I concentrated on, the Redbook won the day. But of course, by definition, the two versions were different. The Redbook was either downsampled from the higher res version (that the MQA version was folded from) or they were different masters. Beyond that, even though I've tried to understand the maths behind MQA, it is all beyond me (thank gawd).

Yes but really any machine-instigated dicking around with the signal is unwanted, full stop.

Well purism of course is a honourable pursuit Tom and I for one would always try to stick to that road when I can (e.g. liking NOS Dacs). However recently I have been 'dicking' around with DSP room filters and the results so far are very encouraging.

Just to be provocative (and also friendly!) isn't implementing an RIAA curve on vinyl tantamount to 'dicking around with the signal'?

[montesquieu]

Just to be provocative (and also friendly!) isn't implementing an RIAA curve on vinyl tantamount to 'dicking around with the signal'?

The RIAA curve is a global standard (set in the US) which sets out the precise way a recording needs to be processed to get it to fit in a groove playable by a stylus.

Without encoding in this way (effectively, reducing the amplitude of bass frequencies by particular proportions around a particular frequency) then a standard groove width would be impossible (or at least a standard groove width that had a decent frequency range). Of course once encoded on the record, in order to be played back this encoding has to be decoded, or 'equalised' by boosting bass frequencies in an inverse curve to that applied when the master stamper was prepared.

Some kind of signal encoding was applied to 78s as early as the 1920s, and throughout the era of 78s and early LPs, every company - Columbia, HMV, Victor, Parlophone etc - had their own version in the form of different turnover and rolloff points. Some early preamps had controls that allowed these to be varied by record label.

The situation was standardised under RIAA (Recording Institute of America) auspices in 1956 and became a global standard (turnover point and rolloff amount). This in turn allowed phono preamps to be standardised too, so nearly all modern ones don't have options to vary the parameters of the curve.

Some specialised ones such as the Slee Jazz Club do, however, and these can be used for archiving or for direct playback of early cuts that use pre-RIAA encodiing/equalisation.

Anyway, it's not really dicking about, to answer your question as it's inherent in all vinyl replay and, in modern times, standardised.

[Edward]

Playing devils advocate here Tom, MQA are trying to establish a global standard as well, just as RIAA did all those years ago. But imo MQA is a solution to a non existent problem.

Thanks for details of RIAA.

Looking forward to having a listen to the Silvercores soon btw.

[montesquieu]

Playing devils advocate here Tom, MQA are trying to establish a global standard as well, just as RIAA did all those years ago. But imo MQA is a solution to a non existent problem.

Thanks for details of RIAA.

Looking forward to having a listen to the Silvercores soon btw.

It's not a non-existent problem if you are a giant copyright owner worried about the amount of digital content out there they don't have control over. Rights management - cui bono?

Just tell them to naff off!

[Edward]

Oops - I meant a non existent problem from the consumer's perspective.

[jandl100]

You certainly have. Still using the Lyngdorf SDA2175 you sold me and the A1 FBP Pre. ��

Ha!
Excellent.
Nice bits of kit, good that you are still enjoying them!

[jandl100]

Just to be provocative (and also friendly!) isn't implementing an RIAA curve on vinyl tantamount to 'dicking around with the signal'?

Yes.
But it would sound rubbish if you didn't dick around with it.

[montesquieu]

Yes.
But it would sound rubbish if you didn't dick around with it.

More concise than my version but just as accurate!

[Macca]

IWell purism of course is a honourable pursuit Tom and I for one would always try to stick to that road when I can (e.g. liking NOS Dacs). However recently I have been 'dicking' around with DSP room filters and the results so far are very encouraging.

Just to be provocative (and also friendly!) isn't implementing an RIAA curve on vinyl tantamount to 'dicking around with the signal'?

An NOS DAC is technically less accurate than one that oversamples, so less purist. DSP is correcting the frequency response anomalies caused by the room and/or loudspeakers. So arguably purist.

[Edward]

An NOS DAC is technically less accurate than one that oversamples, so less purist. DSP is correcting the frequency response anomalies caused by the room and/or loudspeakers. So arguably purist.

Good grief Martin, you are like my wife - telling me I've got everything the wrong way round. You are both correct of course!