[elunkenheimer]

I have a very well built Super Pas 2 from the 80's but one channel now plays quieter, more rolled off in the bass and treble than the other. I have changed out the tubes with now change in sound. Thoughts of what is happening?

[aln]

Could be a capacitor- but with vintage equipment it might be a good idea to send it in and find out for sure. 

[avahifi]

Your issue is almost certainly simply dirty contacts in the Tape/Input slide switch, the switch in the lower left corner of the faceplate.

Get a can of Caig Labs DeOxit D-5 spray contact cleaner from Parts Express, unplug the unit from AC power, remove the cover and bottom plate, and spray into the switch from the side and then work the switch back and forth 20 times or so.  That likely will resolve the issue.

You can spray into the selector switch, blend switch, volume and balance controls, tube sockets, and even the back panel jacks while you are at it.  Excercise each control function several times after spraying. An old toothbrush is nice for cleaning the back panel jacks.  Parts Express may have little brushes designed to clean the insides of the RCA jacks too.

Put a thick old towel under the unit to catch the excess runoff from the contact cleaner.  It won't hurt anything and will eventually dry up.

If this does not fix the unit, please give me a call at 651-330-9871 for more help.

We have not ever had a capacitor failure in a Super Pas Two or Super Pas Three so that is not likely an issue.

Regards,

Frank Van Alstine