[HAM] Best 12AU7 - now 6550

[David Anderson]

On Mar 8, 2008, at 4:11 PM, Keith H Clark wrote:

> Kt-90's are not a particularly good match for that circuit. KT-88's  
> are much
> better.

As I've noticed is the norm with you, Keith, we get a critical  
response with no technical explanation whatsoever.

In my 122 amplifier, KT90s draw the correct bias and sound good. They  
draw the same heater current as a 6550.

Al Goff sells them on his site as a "high performance 6550 replacement."

What's the problem?

David Anderson