2. amps-preamps
  3. 193642-3931

Help me mod my tube amp

Hi all,

I'm interested in modifying my Prima Luna Dialogue 4 amp. The amp is about 15 years old and still sounds pretty good. But in the past I've had fun modding preamps and speakers and seeing what can be improved, so I'd like to try improving the SQ of this amp. I haven't modded an amp before, so I open to suggestions about capacitor upgrades or anything else. You can see a picture of the internals of the amp here. This amp resides in a secondary system, which is:

Mac mini --> Benchmark Dac3 --> Prima Luna Dialogue 4 amp --> Dali Phantom S-180 speakers + Rhythmik F12G-SE-PEQ subwoofer (via high level speaker input)

Power: dedicated line --> Maestro outlet --> Shunyata Hydra 8 power conditioner. Cables are Shunyata and DH Labs.

Current tube configuration in Prima Luna amp: GE Military stock 12AU7, Gold Lion 12X7, Tung Sol KT120

These days, I tend to like things on the slightly warm side of neutral. I appreciate increased resolution, but not at the expense of organic tonality and musicality. Any help would be greatly appreciated!

Bryon

 

bryoncunningham
bryoncunningham OP
897 posts
 

Update on this little project on my Prima Luna Dialogue 4 amp...

I upgraded the capacitors on the input stage with Dueland CAST-PIO Hybrid copper/silver foil caps. I also upgraded the capacitors on the autobias board with V-CAP ODAM caps (see attached pic).

Side note: The work was done by Blackie Pagano in Los Angeles. First time meeting him. He was great. Super knowledgeable, professional, and the quality of the work appears excellent.

Also, at the suggestion of several posters, I changed some of the tubes to NOS. For the 12AX7s, I added NOS Amperex with green labels made for Hammond Organ, purchased from Brent Jesse. For the 12AU7s, I added NOS Brimar from Upscale Audio.

And, at the risk of starting a war between Skeptics and Believers, I added a Synergistic Research Blue Quantum fuse on the autobias board.

The cumulative results are: better resolution, better soundstage, better tonality, and lower noise floor. Altogether, these were very worthwhile upgrades. I always have fun upgrading components and seeing (i.e., hearing) what happens.

I know I didn't do everything suggested so far on this thread. Please admonish me if I ignored your advice and you believe I would benefit from following it. I'm also open to any new upgrade suggestions for this amp.

Thanks,

Bryon

sns
3,907 posts
 

Good choices!

bryoncunningham OP
897 posts
 

Thanks SNS. I read above that you upgraded the resistors in your PL amp. I bought this amp new around 2012. Can you tell from looking at the picture I attached whether the resistors are Takman or something else?

Bryon

sns
3,907 posts
 

PL went to Takman around 2008, yes, those are Takman, you're good to go. I don't think I mentioned this prior, but I also upgraded film cap bypass caps on the big power supply caps, can't recall which caps I used.

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