Tom:
The original Sunn units from 1965 thru 1970 rated at 60 watts RMS used the Gold Lion KT88 tubes. Models included the 200S, 100S, Sceptre II and possibly ohers. Later the KT88's were replaced with 6550's in order to reduce costs.
Conrad
: I've heard that some of the older Sunn heads were optimized for the KT88. Is this true...and which ones?
: Thanks,
: Tom