Narrow Panel Deluxe question

[Earl]

...what most refer to as the 5E3.

Just from looking at the schematic, and it's similarities with the Champ (aside from the twin 6V6's), I had assumed that this was a Class A P/P output section.

I've read statements of AB and A from some pretty smart folks...and just would like to see what the concensus is.

This applies to the original design. IOW, what was this 5E3 originally 'intented' to be?

[Bruce / Mission Amps]

...what most refer to as the 5E3.

Just from looking at the schematic, and it's similarities with the Champ (aside from the twin 6V6's), I had assumed that this was a Class A P/P output section.

I've read statements of AB and A from some pretty smart folks...and just would like to see what the concensus is.

This applies to the original design. IOW, what was this 5E3 originally 'intented' to be?

I would say, to be fair, only Leo Fender would know the answer to that.
I think they are PP, Class Ab1 with just high idle current.

[Paul P]

Just from looking at the schematic, and it's similarities with the Champ
(aside from the twin 6V6's), I had assumed that this was a Class A P/P output section.

A clearcut answer to this question is hard to find. The big difference between
a 5E3 and a Champ is the phase inverter and its driver. Since I don't have a
5E3 (yet) to look at with a scope all I can say is that it's probably class AB if
the PI can drive it into AB (and if the cathode bias will let it) and class A if it
can't.

Surely Bruce knows the definitive answer to this

Paul P

[Earl]

More than likely, you just can't tell...unless you measure it. And *if* you use the strict definition of "A", with a 360 degree full power plate conduction angle - it's possible that even a tube change could knock it into, or out of the class definition.

Tubes are generally spec'd in their center of operation, and the saturation and cut-off points probably vary quite a bit, between tubes.

What I've found is that a LOT of Leo's amps (the old ones) came pretty much right out of the old Receiving Tube Manuals...and I'll bet there's a very similar schemo for a "5E3" in one of them ol' books.