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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.
128x128davide256
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davide256 OP
399 posts
 
so after 10 days of loving the KT-120's my pre and driver complement of tubes has been turned totally upside down. The Amperex 12AT7's are out because of audible gain distortion, all NOS Mullard CV4004's now. I've rolled the KT-88's back in a couple of times but they sound so emasculated in the bass by comparison that I'm back to the KT-120's in short order
wolf_garcia
6,708 posts
 
I love the sound of my recently acquired NOS Mullard 4024s (replaced my JAN Philips 12At7s due to one failing)...and they seem reasonably priced.
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davide256 OP
399 posts
 
so just an update on current tube rolling. The KT-120's continue to sing...just plain better than the cryo GL-KT-88's all around in the amp. And tube distortion in the pre section is more mercilessly exposed. I've acquired some ribbed plate Telefunken 12AU7's for the back pre sockets, cleaner, better bass, more detail that the Siemens I was using. Flipped my entire inventory of 12AU7's through front sockets again with the Teles in back... 12AU7's just sound wrong in the front sockets, low level details fuzzy, more distortion. Had settled on some Mullard 6201's (12AT7) in front, after putting Telefunken in the back sockets they were still detailed but too bright and I isolated them as a source of low level tube distortion. The Amperex world globe 12AT7's are now back in as more musical but their bass waffles, highs are a little rolled. Likely to pop for Tele or better Amperex tubes in the next 30 days.
At this point with the Teles in I have achieved my goal of retiring the CJ PV10A pre and using the PL pre section
davide256's avatar
davide256 OP
399 posts
 
Alright, if you have this amp, listen up. Running NOS (1960's)Siemens 12at7 tubes with triple mica in the front sockets and Telefunken 12Au7's in the back sockets is a match made in heaven. Gobs of low level detail, no tube distortion, no edginess and superb low bass tone colors. The CJ PV-10A is completely retired now, sounds veiled compared to the PL integrated with this tube configuration and Rel cap upgrades. Nice to be finally satisfied and ready to focus on other system areas.
davide256's avatar
davide256 OP
399 posts
 
Back to this thread after a while. In the past year I have made the following changes

1) the front 0.22UF caps are now clarity CAP MR's
2) the follower 0.1UF caps are Rel CU caps with 0.01 TFT vCAP bypass caps
3) the power tube 0.22UF caps remain Rel theta's because of space limitations but bypassed with Rel Teflon 0.022UF caps

As these changes were made it became clear that the 12AT7's did add distortion, I now run Telefunken 12AU7's for all pre-sockets.

This is detailed, airy but it does not match the CJ for lower midrange weight, had similar criticism when I had Rel 0.22 teflons in the front sockets before the MR's. I have ordered some VCap CU's to replace the Clarity MR's as these are reported to shift balance to improve lower mid range, will report back in a few weeks after they are installed and have some hours on them.
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