300b, x45, 211, etc.

Glassaud,

You bring up a good point that can be extended to many 300B amps. In my opinion, many commercial 300B amps use the wrong driver which leads to the problems Glassaud describes. These problems contribute to the general opinion about 300B's that were mentioned in post by Gregm. This is probably due to manufacturers having to use readily available tubes rather than rare and hard to obtain tubes. The 6SN7 driving a 300B is a common design but with common problems. In think the 2A3 and 45 are easier to drive so they don't have this problem.

About Klipsch - once the man, always the man. He and Bob Carver pretty much to my mind are two of the great contrarians of the audiophile world.

I hesistated to bring up the Rocket, but it is a cool design, and with the single-ended-like output (though not 100% there) it was definitely the way for me to get my feet wet and still have a lot of choice. I have toyed with getting rid of it, but never can quite pull the trigger when someone offers me money. I may go so far as to say it's Had's most original design.

Rchau - interesting about the 6SN7 topology and implementation with the 300B. Can you explain - I'm interested. What would the other ways of doing it be?

Friend

As you give up watts you gain communication of emotion, realism, refinement, and resolution. The 45 is a VERY musically accurate tube. The 211 offers more power but at the expense of the aforementioned.

Studio 1

While I've heard amps with just about every tube type, here's what tubes I can comment on in context of hearing all on the same system -- mine -- but of course in different amps:

300B -- SET, PSET, PP
845 -- SET, PSET, PP
45 -- SET
KT88 -- SEP, PSEP, PP
EL34 -- SEP, PSEP, PP
EL84 -- SEP, PSEP, PP
211 -- SET
2a3 -- SET
PX25 -- SET

Amp design, circuit topology, quality of transformers and related circuit parts, and even the tubes you select all have profound effects on amps built with these tubes. But there are some characteristics that seem attached to the tube type itself, which shine through differences in implementation.

45: Penetrating intimacy in the midrange, soft top, deep natural bass. However, even on 101db/w/m Zu Definitions, the dynamic limits of a 45 amp in SET configuration are so acute that it is not practical in American listening spaces. The first watt may be critical, but your average SPL doesn't have to be all that high at 12' distance for you to run smack into the dynamic compression (and distortion) of 2 watts more often than you like. Music with muted dynamic range, however, can be beautiful through this tube. I wanted to be bowled over by the Yamamoto but the dynamic limits couldn't take the 45 all the way.

2a3: Similar limitations as the 45. A little less neutrality than the 45, more romantic. Lush.

300B: A big 7 or 8 watts makes a difference in maintaining dynamic clarity. Magical midrange richness is a real trait, easily identified. Rising harmonic distortion in the bass region generates characteristic bloat that can be designed out at a substantial price. Treble "spray" is lush and exciting but with some tubes, like mesh plates, is on the far side of real.

845: Big, meaty tone. Much more bass discipline than 300B and top end extension is more neutral. Midrange is unmistakably triode and rich, but gives up some of the 300B's delicate articulation. Dynamic slam however walks all over the 300B, even when that tube is used in PSET configuration for similar power. The quality that most sticks out with respect to the 845 is its sheer drive. On some speakers, this tube is unbeatable, except perhaps by the Godzilla T-1610. The 845A, 845B, 845C, 845M, KR 845 and the vintage RCA or United are all different enough to overwhelm these distinctions.

211: Similar to 845 but a little drier.

EL34: Warm, round sound. No one ever regretted listening to an EL34 amp.

EL84: Sweet, open, driven, with surprising bass discipline in SEP topology. Amaze yourself and embarrass many high-buck SET amps with an Almarro A205mkII.

KT88: Take-charge tube with speed, transparency, tone. Strong tube that can give you up to a solid 15w/ch in SEP configuration, with a "whiter" more objective sound than most triodes, and very fine tonal and detail balance. The Acoustic Masterpiece M101, for example, can take a lot of triode amps to school.

PX25: Best bass I've heard from a triode tube in SE. This is the "objective" triode, stripped of the 300B's up-front emotion, with a few extra watts over a 45 to put the vice-grips and some kick to a speaker cone. Lacks the emotional romance of the 300B, but midrange is open and fluid, just a tad tonally anemic. The top end dispenses with the 300B's spray. The Audion and Art Audio PX25 amps are the smoothest segue into low-power SET for someone coming from Push-Pull.

I can say more about each tube, but is this a start for you? For reference, my systems actively use 300B, 845, and KT88 amps today.

Phil

Interesting no one brought Gohzirah or the PX25. Two tubes I have not been lucky enough to hear.

If I were giving advice, which I don't, I would advise someone interested in tubes to find a really high quality integrated like a Manley Stingray featuring the EL84, if they weren't sure they would enjoy using tubes or were unsure about their competency with biasing, etc. Or I would suggest a KT88 amp like the Cary SLI-80 (comes with 6550, which is very similar and can easily be changed out with the 6550's sold). KT88's being the most lucid musically of the bunch. Then work towards an extreme - either single-ended topology, 300B, etc. I would not dive into tubes at the 845 end of the spectrum, unless I had more money than most, or was accustomed to changing out very high-end components every year or two - because if you hate your tube amp which is the size of a Yugo and puts out as much heat as a wood burning oven, you're still stuck with it.