HDOA opamp

[Hamish]

Hi everyone,

I'm nearly finished my first (discrete) power amp (gainclones don't really count), and i now find myself in need of a preamp. The initial plan was to do it with some 12b4a's (and it will happen, but my budget has been SERIOUSLY blown on the amp, and tubes sure aren't the cheapest things around).

Basically, i found this circuit and it looks interesting and up to the job in the interim. I was wondering if anybody has had an attempt at this circuit, and there impressions of it. Properly biased it should drive the snot out of anything put in front of it. I have a few opa111's i've been saving for just such a rainy day.

I was also wondering if this could be used with a non-inverting opamp configuration, and any changes that may be needed to do so.

Any help would be greatly appreciated.

(And i hope to post some pics of the finished amp here when i'm done. Everyone i know just shakes their head in disgust when they find out the time and money i've spent on it. "But i can get one for $200 with 1000watts, AND a cd player!". It's nice to know that some people appreciate the time and effort

[millwood]

this is one of those "bootstrapped" opamp designs: the power supply to the opamp "floats" in order to expand its output voltage swing.

It is a proven design, but not the greatest in sound quality (not that it sucks). I have used it as input-driver stages for power amps with no problem.

what do you need that much voltage swing? using a gainclone may not be a bad idea if you need a lot of voltage.