Which tubes are the best?


Hi folks, I just got a Muzishare X7 integrated amp. It is beautifully made and sounds like it has a lot of promise. Even though I'm just breaking it in, I am thinking about tube changes. Why? It's just what I do. 
I'd like your opinion on the best replacement tubes, meaning smoothest, most "tubby" and mellow tubes. 
I won't be chasing NOS tubes. I'd like your experience with Gelenlex Gold Lion, TungSol, Mullard, Telefunken, or?,  etc. of current manufacture. The amp uses KT88, 12ax7, 12au7 and CR34 rectifier. 
Any thoughts about KT88 vs 6550 would be appreciated. I used to prefer 6550 way back when. 
Any information would be appreciated. Yes, I could go through all the old posts but I do have vision issues after four operations and that's why I'm asking straight out. 
Thanks in Advance. 
Back in the day, I used to do some serious tube rolling. The absolute mellowest, most laid back and detail rich tubes I ever found were some Mullards advertised in the back of Audio magazine. They had Magnus Organ printed on them. They were amazing. Unequalled. Ten years ago, I was cleaning out stuff and took a box of my small tubes to a local dealer. Some guy gave me $350 for them. Wish I still had them heh. 

fredcdobbs

Showing 1 response by noodlyarm

Tube rolling can be fun, rewarding, and expensive!

I've got a PrimaLuna Dialogue HP Integrated; your Muzishare X7 seems to be of similar design so I'll share where I've landed.

Disclaimer, I've got XStatic electrostatic speakers combined with a bit of age-related loss of high frequency hearing so I tend to like slightly brighter sounding tubes in my PL.   YMMV...

I'm running 8 Tungsol KT150 power tubes.   This was my first big upgrade from the stock PL EL34 tubes.   This brought out much more depth and punch to the bass while still preserving the warmth of the midrange.

I played around with the 6 12au7s and my favorite combination at the moment is: Radiotechnique in the center preamp locations with the Gold Lion's just outside of that.   The Cathode followers are NOS RCA Cleartops.   The Radiotechnique are definitely on the bright side so I may swap them with the Gold Lions and give that a whirl.   These changes significantly increased the high-end extension and energy bringing a nice balance to the overall presentation.

It is remarkable how you can fine tune the sound by swapping tubes.  You can't make a bad device sound great with just tubes, but its all part of the complex system to tweak it to your tastes.

Not trying to hijack this, but don't forget to try a different fuse.   The SR Orange change was also noticeable.   I describe it as making the black parts of the music blacker thereby letting the instruments stand apart and increased the detail.   Electronically, perhaps it just lowered the noise floor?   I don't know, I just liked the change.

Enjoy the experimentation and don't forget its all about the music and your ears.