Re: Any reason to build discrete OpAmps for High Quality Audio?

From: Ban (bansuri_at_web.de)
Date: 07/26/04 

Date: Mon, 26 Jul 2004 04:01:20 GMT

Ken Smith wrote:
> In article <ce1kri0i3p@drn.newsguy.com>,
> Winfield Hill <Winfield_member@newsguy.com> wrote:
> [...]
>> Did anyone mention the LT1115, or the LT1028 and LT1128 opamps?
>
> Above the audio band the noise of the LT1028 rises to about
> 3nV/sqrt(Hz) at about 300KHz.
>

Lately I saw some website where they were all crazy about a high-frequency
CMOS opamp(forgot the exact part number) because the distortion and noise
was supposingly a little bit less than the AD797. Looking at the data***
you could see the 1/f corner frequency at about 1.3kHz, giving more than
80nV/rtHz for 15Hz, more than 25 times the value of the bipolar amp.
But these idiots really had no idea, any irrelevant data was given
importance and then you should see, each opamp was sonically described in
high end terminology. Grainy, sharp, smooth as butterscotch... They were
offering small replacement PCB with the most suitable(usually the most
expensive like OP627) "upgrade" to solder into CD-players or whatever. But
the decoupling caps were missing on that board, it relied on those on the
original PCB (if there were) and consequently made good oscillators.
But then they created a "flock" of stupid followers like that guy Hoffmann,
an utter fool without any engineering knowledge. There is even a forum, it
is moderated by him and he throws out any critical comment and bans you from
his site. And once you have fallen into the hands of these Quacks, they are
recommending all kinds of "tweaks", just to milk as much money as possible
out of their followers. 

-- 
ciao Ban
Bordighera, Italy
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