thanks. i am not sure i will. just investigating in case of...BTW i assume any KT88 will do the job (i mean within the KT88 they are all the same? so no need to spend lots of dosh). tomorrow my icon audio passive preamp is arriving. this will mediate, passively, between my arcam 192 and the prima luna power amp. then i will enjoy the direct effect of the valves, and decide whether to upgrade or not.