Another Example Of The Gregory Mark XX Tube Guitar Amp

This is another example of a Gregory Mark XX tube amp. This one is in good condition and differs considerably from the two examples I have seen prior to this one. There is now three different versions of the Mark XX that I am aware of.

	This is the front of the amp. The control face has different graphics from any other examples I have seen. It also has the early grille cloth style with the diamond pattern on it.
	This most obvious difference between this and the other example which looks very similar is that this one has only one speaker instead of two.
	The speaker appears to be an old alnico type made by Jensen. I do not know if it is the original speaker that came with the amp or not. I tend to think that it wasn't since every other Gregory amp I have seen uses a Quam-Nichols speaker. But then again, every Gregory amp seems to be unique somehow, as this one certainly seems to be. Your guess is as good as mine!
	Here is where things get really interesting: It has two 7F7 preamp tubes, a 5U4GB rectifier tube, and two 6L6WGB power tubes. Aside from this version using a completely different set of tubes from other Mark XX examples, the 7F7 (an octal dual triode) is a very unusual preamp tube for a guitar amp. This version appears to be capable of 40-50 watts of output power as opposed to 20 watts for the version with 7189 power tubes. I have my doubts as to whether or not this is the original factory made version of this model. It appears to me that it may have been modified by someone at some later date to use different tubes, etc. The aluminum foil shielding above the chassis is certainly out of character for Gregory amps.
	Here is a partial view of the inside of the chassis. Uses the typical construction techniques of the early Gregory amps. Special thanks to Mike Wiles for contributing the information on this amp.

This example appears to have had a pretty good home all these years. Exact date of manufacture is unknown. One thing that strikes me about these Gregory amps is that every one of them seems to be a one-off. It seems as though even two models that are from the same time period that should be identical rarely are, sometimes not even cosmetically! That just adds to the mystique of these old amps.