The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Phil Allison"
References: <3FsT9.19037$oS1.email@example.com> <firstname.lastname@example.org> <25zT9.20644$jM5.email@example.com> <firstname.lastname@example.org> <6P2U9.21562$jM5.email@example.com> <firstname.lastname@example.org>
Subject: Re: Mosfet amp desigh sought
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
Date: Tue, 14 Jan 2003 07:23:58 +1100
NNTP-Posting-Date: Tue, 14 Jan 2003 07:13:31 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"Bill Sloman" wrote in message
> "Phil Allison" wrote in message news:<6P2U9.21562
> > >
> > > Like I said, it depends how picky you are about distortion.
> > ** That remark is quite ambiguous. Do you mean audible THD or
> > it takes a spectrum analyser to identify at -130 dB ?
> The remark is entirely unambiguous - both of your examples could be
** That is the definition of ambiguous. The meaning is unclear since
several meanings can be included. See any dictionary Bill.
> > There is> no such thing as "NO crossover artifacts" in a class B or
> > > amplifier,
> > ** No equals "no audible" which equates to circa -85 dB compared
> > watt.
> This is an oversimplification.
** What ? Sub threshold sounds are audible ? Since when ?
> Bob Stuart of Meridian has presented a more nuanced view.
** More ambiguity Bill. "Nuanced" = what ? Quirky ? Hypothetical ?
BTW The people you quote have vested financial interests - best leave
them out of a sensible discussion.
> > > > though you can get them down to the level where they are
> > > difficult to detect, let alone hear - the driver stage is always going
> > > to have to slew through a few more volts than the output, so there is
> > > always a non-linearity around the zero current output, though you can
> > > smear it out quite nicely.
> > ** Lateral mosfets self bias at around 120 mA so you have class A
> > operation typically up to 200 mW or so with a 8 ohm load - this equals
> > listening level of around 80 dB SPL. Any crossover non-linearity
> > above this level and measures around -80 dB to - 90 dB compared to the
> > output. That puts it below the hearing threshold.
> I think Bob Stuart was arguing back in 1991 - in the context of
> digital audio - that the hearing threshold could and did get below
> that level in certain, rather specific circumstances.
** So what ?
There is *no way* it is audible with the masking effect of the wanted
signal at 80 dB SPL.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup