[tigerstrat]

The bass amp in the John Kahn photo is a later model (post '75) Fender Bassman, with the knob to the far left being a master.

I think you might be referring to a Bassman 100, which does have a Master Vol(on the far right, as you face it), however those have 4 knobs on Ch 2, whereas this amp clearly has 3 knobs on each channel, plus the extra.

I looked around in the Field Guide and I think it's most likely a Bassman 6G6-A from '62-'64, http://www.ampwares.com/amp.asp?id=26

Here it is Blonde, with the white barrel knobs


Here it is as a Brownface, knobless

[tcsned]

Kahn was the perfect bassist for JGB IMO - it was a tighter unit and Kahn was the tighter bass player. Phil was the perfect bass player for the Dead. Looser unit = looser bass player. I don't think either one would have been better playing in the other band. Not that Phil couldn't play in the pocket and Kahn only played R-5 bass lines.

As to the Jaco v. Danko debate - kind of similar to the Lesh/Kahn comparison. Jaco was much more of creative and certainly a technical wizard but Danko laid down a pocket big enough to drive a truck through. Though none of 'em could hold a candle to James Jamerson IMHO.