I have a Vintage Collins 30L-1 amp. I would like to run behind a Icom 7600 transceiver.
The 30L runs fine behind my (also vintage) TS-520 (most likely due to the 520's pi-network tuning) but when run behind the 7600, the 7600 fold's back power out rather sharply.

After putting in a new set of "Taylor 811's and re-tuning the input's on the 30L-1 I can get almost full output on the 30L-1 on all band's except 75 / 80 (presents an almost infinite SWR to the 7600 on 80) , on the other band's, the loading control barely get's off the CCW stop before the power output is reduced.
All input capacitors have been checked and are well within spec. , ALC has been tweaked and checked.

Any good thought's , recommendations, or experience would be appreciated here.