Originally Posted by ekkybedmond

Hi,
owner of an old JCM900 50W combo; this is the EL34 version and a.t. Bob at Eurotubes it plays on 6L6, KT77 and also JJ's 6V6. Tried them all, no problems. Just measure the PLate Voltage beforehand to find a suitable tube.
The 6V6's are great, starts cranking before the roof takes off. Of course a Weber Silver Bell Alnico 75W helps .. instead of the G12T-75 Celestion which is horrible in this amp.