tube upgrade for first sound

I concur with the Siemens 7308 suggestion, and would also add Amperex 7308 PQ made in the USA. Ever-so-slightly softer mids than the Siemens, and a good choice when running a SS amp with the First Sound.

thanks for the suggestions. I have tried both the Russian NOS 6H23s and the Siemens gold pin 7308s since starting this post. The 6H23s are a nice improvement on the stock tubes. They are smoother and have a bigger soundstage, and I think they are a good value, but the Siemens took me to a new level! They are unbelieveably fast and transparent, much more low level detail, better width, depth, better placement from front to back, more natural voices----you get the idea. Unfortunately, they were obscenely expensive, but worth every penny to me. Now I understand why Emmanuel Go recommends them for his preamps.

Amperex 7308s (USN-CEP, or JANs, or PQs).

AMPEREX PQ A-FRAMES, HOLLAND MADE MULLARDS & TUNGSRAM WERE THE BEST I'VE USED. THE SIEMENS WERE TOO MUCH LIKE SOLID STATE.
THE AMPEREX & MULLARDS LET SECTIONS OF THE ORCHESTRA LIFT OUT OF THE ACOUSTIC ON CRESCENDOES JUST AS IN LIVE PERFORMANCES.
THE ABSOLUTELY BEST MIDRANGE WAS FROM EARLY PRODUCTION (50'S) BUGLE BOYS, BUT THERE LIMITED DYNAMICS/EXTENSION WAS APPARENT ON ORCHESTRAL RECORDINGS, BUT ON SMALL SCALE RECORDINGS, THEY ARE THE BEST.
FOR NON-CRITICAL LISTENING, THE ROCKET LABEL 6H23'S FROM UPSCALE AUDIO WERE A GOOD CHOICE FOR ME.

CORDIALLY,
RAMSES

an old thread that i would like to add to:

Stock: no sluch, but a bit cold to my ear, not as transparent as others.

Siemens 7308 Gold Pins (Emmanuel's favorite - i got from stewart at santuary of sound)): awesome imaging and soundstage - very quiet and refined. Maybe a bit analytical if im listening to female vocals. My brain loved these the most, my heart the least

Phillips Miniwatt pearl cryo's 6DJ8 (from www.tubeworld.com) 1959 german made: the opposite of the Siemens: warm and smooth as can be. Smaller soundstage, just a bot rplled off and less transparent than the Siemens, but the smoothness and roundness of the notes, it's emotional impact (esp at night with a merlot listening to vocals) is really unbelievable; handily eats the other tubes for dinner on the right matl.... These are what i keep coming back to, though clearly not as "hi-fi sounding" and not as good at rock or complex jazz. My heart loved these the most, my brain the least.

Finally Amperex PQ 6922 white lattereing D getter from early 1960's (got here on AG from Sam): a cross bwetwen the Simens 7308 and the 6DJ8's. These are my all-around winners, though my heart still falls hard for the 6DJ8's warmth, and depending on maoood and material, I'd prefer the reference quiet and refined sound of the Siemens.

If anything, im learning that tube rolling is like everything else in life - there are no absolutes, just trade-offs.