This looks like a neat way to take the ST-335 for a ride, 12VDC to HV switcher PSU. They should work fine for the Ikes as well, with one per channel. Filaments wil have to be re-wired for 12V instead of 6V (or build another step down switcher).
http://www.audiohobbyist.com/diyparts/p ... carpsu.htm
/ed B in NH