MIT wrote:

didnt mcproud publish this in the 1950s?i guess what is old is new again.
mit

"John Stewart" wrote in message ...
| More complete articles on this unique hookup can be found in Glass Audio
| Magazine, Issues 2 & 3, 1999.
|
| Cheers, John Stewart
|

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McProud did publish a couple of circuits using the 6AS7 as the output tube. But both used an
interstage transformer to get the necessary grid drive. The circuits are in Volumes 1 & 2 of Audio
Anthology.

Far as I know no one ever published this circuit using a boot strap type driver for driving low mu
triodes. Another point that makes it unique is the application of an UL OPT to get the correct
drive. But if you have a look at the 2nd article in Glass Audio Issue 3, 1999 you will see I have
devised a way around the tapped OPT problem as well!

Boot strap drivers are used by Gow & McIntosh in their Unity Coupled amp & by the various versions
of the Circlotron, like Electrovoice. And Norman Crowhurst used it in his 'Twin Coupled' amps.

I'm curious so if anyone knows of a driver circuit for triodes such as I've devised please let me
know. This one is probably patentable but when one considers the potential market today the lawyers
would get all the money.

Cheers, John Stewart