Dynaco ST-120 amp output cap coil?

Got a ST-120 amp with bad output cap. The new caps are much smaller.The wire that is coiled around the output well I need to do a coil much smaller. I saw a picture of one that had some wire wrapped chokes hooked from the NEG of the output cap to the binding post. A guy contacted me from another forum and this is what he said. The coil forms an inductor which is wired together with C8 and R18 as a LC filter in the speaker outputs. The resistor provides damping for the filter. This filter rolls off the very high frequencies to help the amp stability and prevent very high frequencies from reaching the speakers. I beleive the rolloff is well above 20KHz. So if what he is saying is true if this is not done right I might smoke my tweeters. Also I was told that a Torrid core choke used in car amps might work. They are made with different values. I guess there is a formula for making a filter? Need some suggestions. Thanks
If I recall correctly, the coil was wound on one of the smaller power supply capacitors so that when transferred to the output capacitor it is a reasonably tight fit. Why can't you just wrap something around your new output capacitor so as to increase its diameter so that the old coil can be used.
Audio Asylum has a Dynaco forum.You could try a post there.
I own one of these in perfect order.They do hum a bit but sound pretty good.[for a transistor amp].They seem to have a particular affinity to Van Morrison and old BBC monitor type speakers like LS3/5a and BC1.