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
901 posts
 

Thanks, SNS. For the bypass cap, I think you're talking about the yellow cap marked "Swellong MPT 630V" in my photo. Is that right?

tablejockey
4,065 posts
 

I'm sure your amp is performing better than it already  is.

How my much in parts/ labor are you in?

"For the 12AU7s, I added NOS Brimar from Upscale Audio."

I looked up the current price to compare what I paid 8 years ago- ouch, but not obscene. Still in my PL.

My 11 year old PL HP will get the makeover as a DIY project eventually. For now, it's a reliable daily driver like my 67 Macintosh tube tuner.

 

 

 

 

sns
3,921 posts
 

Yep, the yellow one is correct.

bryoncunningham OP
901 posts
 

Hi tablejockey,

Here is the parts/labor cost rounded a little:

2 Dueland caps: $150

4 V-Cap ODAMs: $300

Labor for caps install by Blackie Pagano: $200

2 NOS Brimar 12AU7: $300

2 NOS Amperex 12AX7: $300

1 Synergistic Research Blue fuse: $60

Total: 1,310

Now that I'm looking at it all together, it sounds like a lot. But it really breathed new life into this 13-year-old amp. For some reason, I find upgrading existing things more rewarding than buying a new component.

Bryon

bryoncunningham OP
901 posts
 

Hi sns,

Can you educate me... What benefits do people typically experience when they upgrade the bypass caps in the power supply?

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