John Curl's Blowtorch preamplifier

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john curl said:
44.1KHz was a complete Sony artifact. Even Phillips used 50KHz when I visited them in 1974. We used 50 KHz in 1968 at Ampex. Why?


Rumour has it that a Sony hoshot wanted to record a certain piece of music on a single CD, and that due to the length of the piece thaty had to go to 44.1k to make it fit. Could be just a rumour, but I've read it at several places.

Jan Didden
 
In fact the debate about the audibility of pre-ringing has still not ended, but there are some hints that pre-ringing might indeed be a problem.

That´s the reason why some people think it could be a nice idea to return to asymmetric filter design, see for example Julian O. Smith.

Afair Lesurf too has written about some papers on this subject.
 
Jakob2 said:
In fact the debate about the audibility of pre-ringing has still not ended, but there are some hints that pre-ringing might indeed be a problem.

That´s the reason why some people think it could be a nice idea to return to asymmetric filter design, see for example Julian O. Smith.

Afair Lesurf too has written about some papers on this subject.


I may be kicking in an open door here, but maybe we should remember that pre-ringing isn't. What happens is that the main signal peak is delayed and that what we think is pre-ringing is just the start of the signal, slowly (relatively) building up, with a delay, to the main peak.

I hope we can agree that this preserves the causality.

Jan Didden
 
janneman said:



I may be kicking in an open door here, but maybe we should remember that pre-ringing isn't. What happens is that the main signal peak is delayed and that what we think is pre-ringing is just the start of the signal, slowly (relatively) building up, with a delay, to the main peak.

I hope we can agree that this preserves the causality.

Jan Didden

Normally pre-ringing and post-ringing is meant related to the main portion of the signal under observation.

It would be a nice concept, if my digital filters could begin to respond right before playing any signal. 🙂
 
janneman said:



Ahh, you're no longer using the opamp follower, then? I missed that.


Indeed, there is no longer an opamp.

P.S.

This is the final regulator (having regulation preceding it):
 

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This regulator that Joshua_G has designed, is essentially what is used for the low noise regulator in the Vendetta Research SCP-1, 2 for that last 25 years, and it works pretty well, IF the load current is relatively constant. I use a Nichicon Muse or equivalent electrolytic cap in order to not have any magnetic leads on the cap(s) as well.
 
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