SteveD wrote:Just tried the 2466 with a pair of KT88s in the output and was very impressed with the result. :) This is a viable option for anybody who wants a different sound characteristic from their 100W Vintage Modern head. The sound was more edgy and crunchy and the dynamic reaction to the guitar volume pot was retained. The power amp gives a bit more linearity at higher volume which some people may prefer or not; Kt66s have a fatter mid and smoother treble response. Both valve types yield good tones, it's just a matter of personal taste which suits you better. Personally I prefer the KT66s but I know there will be people who prefer the KT88s; especially those who like EL34s.
There are no mods to be done to the PCB. Bias for the KT88s can be set at 60 to 64mV per valve (at Connector 10 pins 1 and 3). There is no real significant reduction in power and therefore volume to be had with this configuration, just a different sonic texture. The amp will live quite happily with either configuration.
Steve, did you get a chance to measure the power output with the pair of KT88's? At first blush I'd think it would be approximate to the KT66 quartet, all else being the same (but this is a guess). Just wondering if the two KT88 solution would give a power drop to those wanting less power from their 2466 head.