RE: [Harp-L] Feedback

["Joel B. Chappell" <joel.b.chappell@xxxxxxxxxxxxxxx>]

Usually the steel core in the speaker output transformer saturates before
the output tubes totally saturate. This "squares-up" the waveform. Most old
amps run a pair of 6L6s at about 25 to 30 Watts in Class A bias conditions.
Overdriving to saturation may force them into Class AB1 operation where they
draw a little grid current but they are all done at 60 Watts. Class A amps
dissipate the same power regardless of drive and usually fall off due to
core losses when overdriven, though the voice coils in the speaker my
overheat and burn out with the distorted square wave signals.

Joel B. Chappell, Senior Electrical Engineer
21 Billings Street
Milford, NH 03055

Rick, I simply mean driving the tube to or beyond the level at which it
makes its maximum power. 

/Greg

> Greg, can you please define "Power Tube Saturation" as it applies to harp
> amps such as the Bassman types?
> 
> Thanks.
> 
> -- 
> -Rick Davis
> The Blues Harp Amps Blog
> http://www.bluesharpamps.blogspot.com/