My 8080 does not exhibit that. The normal (clean channel) doesn't have volume only gain control and the boost channel (distortion) does have both while the 8080 also has an overall volume pot, so you must balance out the two first and then can adjust volume with the overall volume pot. not sure...
The only difference is cosmetically, different colour tolex.
The amp is the same as the regular 3005 mini stack.
There are different version of the 3005 with one with a line out only and another with direct out and headphone plug.
Not sure which one was on the SJ.
For what it's worth, I have and still play my 8080 (big brother to the 8040), it sounds good to me. Never like the seond gen Valvestate (VS65R) but liked the later AVT20. I had, but was underwhelmed by the JTM30, though some might prefer it, being an all tube amp and not some hybrid. Now the...