Amplifier Power tubes - important to sound?

@emergingsoul 

I sell tubes full-time for a living and I think you'll be looking for those elusive Siemens' 6550s for a very long time indeed because I don't believe they exist. 

I love Siemens tubes and I'll tell you the closest thing to what I imagine a Siemens KT88 or 6550 would be/sound like that you can buy is the modernly made KR Audio KT88. At $400 a pop they aren't cheap and they are about as hard to get your hands on as the fabled Siemens 6550s. They are a nuanced, disciplined tube that is subtle in how great it is such that trained ears might appreciate it far more than ears just looking for "more."

Many say the KR Audio KT88's sound like NOS GEC/Genalex tubes. But I doubt too many of the many that say or have other opinions or claimed knowledge about them have ever actually heard them never mind spent the time to listen to them. I swap my KRs for my GECs on a weekly if not daily basis, and have for years, so I'll tell you that in the I don't think they sound similar at all. In fact, I always tell people if Siemens ever did make one, I expect it would sound like this (the KRs). And now I've told you, do what will with that.

Rockets,

Yes power tubes have the most impact on sound. Next are signal tubes. Further, the first signal tube in the series has the most impact on sound.

@mulveling 

How do you like your VAC gear, specifically your amps? I have a couple MC275s I've run as monoblocks in a bi-amped setup (currently paired with Pass Labs xa160.8s.) that I think I'm ready repurpose and/or upgrade.

I had planned to buy a VAC Master II pre-amp this month but I re-tubed a couple for local clients over the past couple of weeks and didn't know whether to laugh or scream when I pulled the stock tubes out of them. So I've pumped the brakes a bit One had a pair of Golden Dragon 6922s in it along with 6 Shuguang 12AX7B's in the phono stage, the other a pair of garden variety EH 6922s, no phono stage. How they can plug a couple of $5 gumball machine tubes into a $30k pre-amp and think it's okay is simply beyond me. You could socket a grilled cheese in that thing and it would sound better. The Siemens E288CC Red Tips sure did.

I’ve come to the conclusion that emergingsoul has no system at all and just wants us to think he does. No one would be as elusive as he has been. Fairly entertaining though. 

Funny they aren’t mentioned yet but the Russian Winged C 6550’s are readily available nos for under $100 each. My favorite power tubes ,and I’ve tried many, are the winged c el34’s and kt88’s.