Primaluna dialogue premium HP tube rolling suggestions to reduce brightness

@johnss

I personally don’t want to mod my amp. Have you experimented with any fuses? I wonder if there is a fuse that would help with brightness?

There are so many things that can be altered outside of modding the amp.

meiatflask

Hi, to answer that properly without guesswork, I tried to find an impedance graph of your "proac tablette anniversary" speakers, but with no luck.
While they are factory rated at 8ohms there could be dip/s maybe to 4ohms maybe in the power regions, and the 4ohm tap from your amp then has a better damping factor (output impedance) to control them at that frequency.

Just go with the 4ohm tap in Triode mode, as this amp is questionable for capacitive stability in Ultra-linear mode. As Stereophile has stated, if you find you don't have enough power, look to either more efficient speakers or a bigger amp. Don't go wasting money on different tubes they will not fix the instability in Ultra-linear mode.  

Cheers George

I disagree

You got a $4500 amp. I say try a CV4003 Mullard or RCA, Raytheonl blackplate organ pull on the cheap.

The chinese 12au7 tubes are to draw attention at first with all the high freq detail, but they are fatiguing...especially the 2 middle ones.

Upscale audio offers a cryogenic treatment.  Any comments on how it will affect sound?

I would listen to Aniwolfe. He and I both have been rolling tubes. He is more experienced than myself in the 12AU7 area so he is a good source of information. Also there is a review of the Dialogue Premium in Stereophile talking about the upper midrange glare and the reviewer swapped out the stock tubes to combat this problem.  I don't agree with his KT120 power tube choice but to each his own. I can't remember the 12AU7's he tried. I would start with cheaper tubes and/or call Upscale and let them guide you.