SET vs OTL

Paul,

I understand that SPLs will be limited when using a 45 SET amp full range. I am willing to restrict my use of such a system accordingly. I am, however, intrigued by the idea of an SET that can deliver the mid-range I have come to expect of such designs (based primarily on my 300B experience) with superior bass response. To be clear - I don't expect LOUD and I don't expect 20 hz.

I can (and have) used powered subs with my 300B amps. This does not address the point that the 45 lovers here have made regarding the superior bass performance of these amps. If I use powered subs, I don't particularly care about the bass performance of the main amp - 45, 300B, or SS.

If I understand the rest of your post, the Audio Note HE version might be a good choice. Any other ideas? Anyone try the Zu for this purpose?

Marty

Martykl,

If you use a powered sub but with high-level inputs - as many people believe is preferable - the bass characteristics of the amp still matter - except for power (current) delivery.

Yes, the HE AN/Es work very well and really do give usable bass to 20 Hz positioned in corners as designed - flat to 30. (I'd say peaks to no more than 85-88 dB in a large room, however. Small room, obviously louder is possible. But AN/Es tend to overload very small rooms with bass.)

I know for certain there are people who have used Zu Definitions with 45 amps with very good results. Those have powered bass, good to close to 20 Hz I do believe.

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.