SET vs OTL

Although I am one of those that expressed a personal preference for 45s and 2a3s over 300bs (I own a pushpull 45 amp and a parallel SET 2a3 amp), I hardly think it is fair to say someone is wrong or inexperienced for have a contrary preference. A friend of mine who owns more than a dozen different amps, many he built or modified, prefers a 300b SET amp for his setup. His custom horn system is 105 db/w efficient and his room is not very large, and he listens at fairly low volume, so power is NOT an issue. In this case it is more of an issue of system matching. The horn loaded bass driver does not go low enough for the punchier, better controlled deep bass of 45s and 2a3s to matter as much, and the slight leanness of his system's upper bass/lower midrange is nicely compensated for by the upper bass bump of the 300b. This is a case of different horses for different courses so no there is no absolute superiority of one over the other.

Martykl, I've heard AN/Es being powered by pushpull 45 amps in a very large room and was actually surprised by the volume that speaker can deliver, given its somewhat modest efficiency. I don't know how it would have sounded with a 45 SET amp however (SET would be roughly half the power). I prefer that speaker a little bit away from the corner because its bass response can be a bit too much in the corner. Because Audionote speakers have a fairly warm warm upper bass and lower midrange response, I would have some concerns with 300bs overemphasizing these qualities. Still, one never knows without a trial.

One more thing to add. There are certain 300b tubes that are better at controlling bass and reducing their loose and overripe upper bass response. I am talking about the Kron 300b. It is no longer made, though new stock is still available. Because of the close relationship between Kron and Emission Labs (EML), it would be worthwhile looking into EML's current production 300b (I use their fantastic 2a3 tubes myself).

Larryi,

First of all I acknowledge that this is something of a matter of taste and also system-matching - as you pointed out, a ripe, bloomy mid-bass *can* be an attraction!

It isn't in the systems I've put together.

EML makes very good tubes but their 300B retains the tube's bass characteristics IME. They may go somewhat lower than most but it is not an tight & controlled, nor as linear in the midbass region, as the 45 - especially the EML 45.

Not sure if you heard an HE version of the AN/E but if not you're talking about 3 dB lower - right about the power difference of SET vs push-pull.

What were the PP 45s you heard?

Paul & Larry,

Thanks for the input.

Marty

PS Paul, I have a different view of crossing subwoofers, but I'm really interested in trying a 45 SET full range, anyway. I'll explore the Audionote further.

Said I owned over 35 SET amps 6 of them-45 SET, 4-OTL. Not that I'm 35. Would happily trade to be 35 again. I will leave this thread nothing worth while here. All I do is design hi-eff loudspeakers mostly for small power amps like SET what the heck would I know about driving loudspeakers with small power or OTL.

Paul,

The pushpull 45 amps were built by a Russian guy named Pavel and were sold through a Washington, D.C. area dealership (Deja Vu Audio). These amps used Acrosound TO-330 output transformers (the feedback taps not employed, obviously). The wiring was all point-to-point. In fact, Pavel laid out the amps so exquisitely well that there was almost no wire used in the amp (lead-to-lead connections).

I have one of these amps, though mine uses solid state rectification (most of Pavel's amps employed tube rectification). Some versions used big Chicago brand transformers.

I like the sound of these amps very much. But, my current amps (Audionote Kagekis) are, better to me (at a HUGE price premium).

Deja Vu Audio is an interesting store. They will run almost any speaker with low-powered tube amps which "conventional wisdom" says are way too underpowered. The store sells Quad speakers, and even the 2805 is connected to a fairly small tube amp. The one solid state piece in the store is a Halo JC-1 amp. I asked about it and was told that it is used purely for comparison -- Vu, the proprietor, wanted a decent, high-powered solid state amp for a reasonably fair showdown.