Super Reverb Crapping out

[Toxophilite]

Hello
My 1980 Super Reverb seems to be crapping lately and not as loud as I remember it being. Lately I've had to turn it up about 4-4.5! and at that point if you play a chord hard, it craps out. mostly on the bottom end. Seems kind of weak for a 70 watt ultralinear amp.
My tone stack is set at roughly 3 across the board with the MV all the way up.
Previously I never really had to turn this amp up past 3 - 3.5
I did some servicing recently, (on another thread) because of this and just because it seemed like it was time
New electrolytics, New plate resistors, redid the speaker wiring. The tubes test well though my Power tubes are getting a little microphonic (older GEs)
Whilst It was a good idea from a maintenance standpoint, it hasn't seemed to give the amp any of it's old life back
Maybe I'm going deaf???

One thing I've been doing for years is runnning a little mini 4 ohm leslie off the ext speaker jack. This has always seemed to work fine.
The schematic and the back of the amp seem to suggest this isn't a bad thing to do.
Thou lately I've noticed the amp to be a little quieter with the leslie plugged in.
(I'm not sure this has anything to do with it, I'm just stating all the facts and I've always been curious about it too)

Any other ideas on things I should check?