Tube synth diy

:
>
> excuse my ignorance too..
> but why do most of the circuits in Waveforms use a 6AG7 diode
> connected, rather than just a regular diode tube?
> Is there some advantage to using a pentode as a diode?
> 


while we are on it... and hoping not being too annoying =:p

... germanium diodes would be OK?

I'm just guessing since I've seen a Ring Mod done with diode tubes instead of Ge diodes...
(I have some 1N60 with 0.22V fwd drop)