Optimizing the Prima Luna Premium Integrated amp

Having had the Prima Luna Premium Integrated for about 7 months now its been one of my goals to retire the CJ PV10A I had been using for pre amp. However from the start the preamp section of the Prima Luna never seemed to measure up to the CJ in deep bass. Recently however I decided it was time to retube the 12AU7's in the CJ, sticking with trusted NOS Mullard CV4003's. Now having 2 pairs of Mullards to play with I was able to do some comparison swapping in the Prima Luna. Lo and behold, putting the Mullards in the rear 12AU7 sockets of the Prima Luna brought the low bass up to where it should be and differences become trivial swapping a variety of 12AU7's between the CJ and the front sockets of the Prima Luna

Mullard NOS CV4003 highly recommended for the back 12AU7 sockets of the Prima Luna Premium integrated. Not so recommended for both socket pairs as the combination becomes too forward in the bass. Funkwerkes 12AU7 and Prima Luna 12AU7 are in use now while I seek a quicker more neutral tube than the Mullard for the front pair.