dont think so because cj ten is a warm pre-amp and mullard is warm sounding tubes
Best cheap NOS tubes:GE, Phillips and Sylvania
LIVING IN CANADA AND NEED TO RETUBE MY CJ PREMIER TEN WITH 6GK5 GE,THEY ASK A LOT OF $$$.SO WHERE I COULD MANAGE TO HAVE A GOOD CHOICE OF GE,PHILLIPS AND SYLVANIA TUBES AT A GOOD PRICE?