45 Type Push/Pull

I have a Deja Vu pushpull 45 amp. I like the sound. It has a tight, dynamic sound that is characteristic of pushpull. It is a VERY good amp. However, SETs do some things better (I own a parallel 2a3 SET amp). SET amps have a more natural delivery--no artificial edge to the initial attack, notes seem to bloom and expand into space, and the sound is more enveloping.

SET amps are often characterized as being a bit short on dynamics. Most often this is really about bass delivery. SETs don't quite deliver the same kind of "punch" to bass notes. I have mixed feelings on that issue. That same "punchy" sound of pushpull bass can sound a bit mechanical and artificial to me (sounds the same no matter the music), while SET bass tends to have more character (changes subtly with the music). But, the extra punch of pushpull may be what some music needs, so it is hard to say what is better. I currently have in my system a pushpull amp I really like (output tubes are Western Electric 349A), so I am not really in one camp or the other.

Jsman,

That is a tough question. It is not so much a case of some huge difference, as so much a matter of degree. In many respects differences between tube types-- 45 vs. 2a3 vs. 300b vs. 211 -- is more significant, and arguably difference between brands can be on the same magnitude (for example an EML meshplate 2a3 will sound VERY different from a JJ meshplate 2a3).

If one is comparing "like" amps-- pushpull 45 vs. SET 45, or PP 2a3 vs. SET 2a3, the SET amps tend to develop a more enveloping soundstage so one feels more emersed in the sound. A really good SET amp is surprisingly dynamic and lively sounding at lower volume levels (the lower one goes in volume the bigger the advantage of SET amps). Good SET amps sound relaxed and lacking in artificial edginess, while to sounding murky or sluggish.

But, good pushpull triode amps, are pretty good too in all respects. The sound of such amps tend to be punchier and tighter (less overhang on notes), and hence, they tend to have a more driving rhythm. This is good if one's system is a bit too polite and laid back. But, an over emphasis on rhythm and drive can give the music the "mechanical" quality I mentioned in an early post. So good quality can become bad, depending on ones taste, system, perhaps type of music, etc. This tighter sound also means that notes seem to decay faster and so there is less of a lingering "wash" of sound (again, good or bad is a matter of taste).

I happen to like both pushpull and SET triode amps. I certainly tend to prefer such amps over higher powered pentode and tetrode pushpull amps. Most of these kinds of amps sound a bit too brittle and edgy to me, and they tend to be lean sounding (lacking in full saturation of all the harmonics). Also, they tend to sound dead and lifeless at lower volume levels.

I am pretty much a low power amp fan. To me, one can tell how good an amp is by how LOW one can go in volume and still enjoy the sound.

Charles1dad,

We are in agreement about the strength of SETs. At higher volumes SETS remain remarkably composed and do not fall apart--they just stop getting louder as their limit is reached instead of breaking up. But, because they do produce so little power compared to other forms of amplification, they can sound compressed when played at higher volumes because they are really being pushed too hard. This is not that evident with most music, particularly pop-rock or jazz. To me the dynamic limits of amps are most evident listening to large scale choral works, such as Rachmaninov's Vespers--I can hear compression at what seems modest volume levels with this work.

You mentioned, above, the Takatsuki 300b. I've never heard that tube. What would you say is the tube delivering sound closest to that tube? I know the Japanese are big fans of Western Electric, so I would guess that is the kind of sound they would try to clone. Of the 300b tubes I've heard, I like the one Kron put out about 10 years ago--quite punchy and lean compared to most 300bs.