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

Showing 2 responses by bryoncunningham

bryoncunningham OP
893 posts
 

Thanks everyone for the input so far. Several people suggested new tubes. As is probably obvious, I am pretty naive about tubes and open to your suggestions.

 

knotscottt: Yes, I run the amp in triode exclusively. I do not know whether the amp can use 12BH7a's rather than 12AU7's. I will try to find out.

russ69: I started using KT 120's all the way back when I bought the amp because I was coming from solid state and I was accustomed to bigger dynamics than the stock tubes provided. But I gather from your comment that KT 120's may be overkill?

johnss, sns, and viridian: Thank you for your specific recommendations. I will investigate options for upgrading each of the things you mentioned.

 

Bryon

 

bryoncunningham OP
893 posts
 

Thanks, nlitworld, for those additional suggestions. I will check out the binding posts and wire you mentioned.

 

Mike B-- Thanks for your observation about the different directions this thread has taken. Both kinds of input are valuable to me. I've used Mullards (can't remember which ones) for signal tubes in the past with this amp and liked them. I think when it came time to replace them, I cheaped out. But I've been taking more of an interest in this secondary system lately, as I spend a lot of time in that room. So I will rethink my former frugality. To my knowledge, I have never heard Winged C 6550's. Do you have the same positive opinion about other 6550's?

Thanks also, Mike B, for the suggestions regarding resistors and capacitors. I have been internet researching potential replacements. Although I have modified preamps and speakers myself in the past, I am going to hire someone to do these modifications.

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