Never Owned a Tube Amp and Want Advice


Hi All, 

I have never owned a tube amplifier before and am planning to purchase one with a minimum of 50 watts per channel to mate with 8 ohm 88 dbl speakers.

My hope is experienced audiogoners will share their expertise regarding how to approach this. While I realize listening is the best way to learn about sound and compatibility; I want to learn a better understanding about brands with less maintenance and longer tube life, how to decide between mono or stereo,can a newbie play with bias or is auto biasing a better first choice, etc.

I would also appreciate what to look for in selecting a used tube amp to identify one that might be in need of repair. For example, with solid state depending on the brand, capacitor replacement can be more of a concern. Any advice on what to look out for or ask about with used tube amps would be appreciated.

A big question I have is how to understand the relationship between power tubes like E34's, 120.s, etc. and, I guess the driver? tubes like 12au7's and 12at7's. That  is to ask which is more critical to the overall sound of the amp? FWIW, I routinely tube roll with my preamps.  

I 've read through a number of threads but maybe someone can point me to good ones I may have missed. 

Thanks for listening,

Dsper
dsper
Post removed 
That's great info @tvad .
Which leads me to question, how large is the OP's listening room?

Which leads me to question, how large is the OP's listening room? 
Listening room is 25 X 15 X 9.  Due to room logistics, speakers are two feet from the front wall and the speakers are about 10 feet from listening position; thus half the room is behind the listening position. 


I suggest reading Robert Harley’s book "The Complete Guide to High End Audio", paying particular attention to the chapters on amplification.
Good reminder to take another look at it. Thanks!

Selecting tubes and tube amps to suit your needs is very subjective, plus there are a bunch of variables that are unique to each situation. Pick a well regarded amp circuit as a starting point, and get your feet wet...you can taylor the types and brands from there as needed.

I’m running two Dyna/VTA ST70s in a vertical passive bi-amp configuration, which allows me to use different tubes on the woofer channels than those on the tweeter channels. They’re all EL34s, but there are differences between brands, and it’s fun to experiment with them. My stock driver tubes are 12AU7, but I recently opted for 12BH7s in the more critical positions...I love those.

My amps have a manual bias that’s really fairly easy to do, and once set, they don’t drift much. No worries if you can use a voltmeter.

I’m driving speakers of average 89db efficiency. I can run the amps in triode mode at 20wpc, or ultralinear at 35wpc. The vast majority of the times I opt for the clarity of triode mode, and almost never feel the need for more power or more volume. There’s so much room ambience, inner detail, and dynamic contrasts that I don’t feel the need to reach ear bleed levels anymore ....100db is more than enough to annoy my wife! Love the tubes, and will likely never give them up because of the glimpse into the studio that they offer. Good luck!