Can the top end of a PrimaLuna Evo integrated be tamed w/tube rolling?

i would only add 3 comments to what has been said already regarding perceived top end harshness of the primaluna evo

1) swap out center position au7’s to mullards or black plate ge or rca’s to get a more ’rounded’ and dimensional sound - the stock chinese tubes the PL’s ship with are indeed grim, esp. the small signal tubes

2) what power tubes are being run in your evo 300? if they are the same ’primaluna’ branded shuguangs they tend to somewhat thin and sharp -- suggest new stock russian made tungsol 7581’s or 6550c’s... once again, for more full, balanced, less etched sound

3) i assume you have played with your triode/ul switch... the former setting should sound more natural tonally, if reducing sense of drive somewhat

good luck

To reinforce what @jjss49 said

I find Primaluna to be nothing like the OP is describing. Of course EVERTHING is system dependant.
That being said, I use silver wire throughout. I have also changed all the stock tubes out for NOS.
The 2 center 12AU7 is where to start.
I find the warmest to be NOS Mullard long plate. CBS HYTRON 5814A and RCA 12AU7 black plates are also a good option. Stay away from Telefunken and Mazda in your situation.

As far as power tubes I've been using
NOS Mullard EL34 XF2's. They have a fuller,  rounder, more meat on the bones type of sound compared to the stock ones. (For lack of a better descrition)

And ofcourse you can use the ultra linear/triode function found on the remote. Triode tends to be a little rolled off on the high end and also doesnt have as much air as ultra linear.

Only after tubes would I look at cables.
It doesn't sound like a weekend is enough time to spend with that amp for experimentation but not a bad way to spend a weekend at all.

Have fun

@jsqt, try some shuguang Nature sound, or black carbon 12au7s in the first 2 or 4 slots. They have a great midrange.

Sorry gang, I'm on the road and pretty tired.  Of course, before you attempt to tame the highs of electronics you should see if you lack enough absorption and diffusion. 

A room that is too alive will act like a tone control, exaggerating mid-treble.  For hard/constricted treble the floor between/behind the speakers are important targets.  try out some blankets or cushions there and see if things improve.

Thanks for all the input everyone. I have swapped out the stock driver tubes for a pair of Mullard 12AU7/ECC82 and found that it has smoothed out the top end, and also centered the balance better which tells me maybe the stock 12AU7s may have had some uneven wear on them or something. 

It is definitely sounding better after listening into the late night last night and again this morning. This morning, swapping back out with the Supernait 3 and the Evo definitely has an edge on transparent realism and engaging sound. I am using the Naim NDX2/XPS DR as the streamer/DAC so that helps quite a bit.

I'm pretty much ready to abandon the idea of trying an EVO preamp with the Supernait as I just don't think the Supernait is working well with my speakers. I have struggled with it since September and the EVO seems to be dialing in right out of the box. 

@erik_squires thanks I definitely have the room treatment covered pretty well in my room. These are some temporary 244 bass traps for corner and first reflections (took them down from my home theater) but I have new ones on order for permanent installation... unfortunately with Covid GIK is several months behind on production and shipping. My November order should arrive the first week of February (hopefully). 

https://www.smugmug.com/gallery/n-nh4Np6/i-b8N2h4n/A