post #31 of 593
1/31/09 at 7:15pm
There is an amp design in the National Semiconductor application note 1651 that I noticed when I was looking at a RIAA preamp in the same document. Not sure if it's ever been built.
National's Analog Edge - July 2007
voltage gain 1000 (60db)
This is usually the killer for opamp based designs as they give up long
voltage swing a minimum of 1200 volts peak to peak stator to stator.
(spritzer will say that 1800 is better and it is) Very few tubes do this
in anything but huge packages, and the number of semiconductors that
can do this is small and decreasing every day.
full differential output absolutely required.
slew rate as fast as possible, >100 v/us and thd as low as possible,
<.01 % or it sounds like crap.
Able to drive 50pf pure capacitive load. Not so easy, especially for
things with opamps in them.
I think what we need, as a DIY community, is an amp that beats all but the top end of the Stax SRM series for just a few hundred bucks in parts and a couple weekends of labor.
yea it would be great if you guys come up with something. Something to compete with the low-mid range stax amps and beat them in bang for the buck.
Oh yea I saw this while I was googling something else stax related:
the STAX Amplifier