SET 45 Amp Driving Dynamic Speakers

Hi jsman.

I'm interested in learning more about your midrange horn. Is it circular? What are your xo points and what is the horn cutoff frequency? I'm also exploring tractrix midrange horns. Right now with a suitable cone driver but also considering compression drivers.

I can play any music I like at any volume I want included levels that would severely damage hearing. This I can do on 6 SET watts easy. I love heavy metal punk blues jazz classical, pipe organ etc I have no limits this is what one can get with careful matching of amplifier ie SET to loudspeaker. Sure SETs can sound wonderful if used in systems that set a performance limit. But they can do it all if you let them. My SETs are driving 4 -15 inch woofer-2- 50lb compression mids and 2-30lb tweeters. With SET the loudspeaker needs be able to work weak magnets small cabinets complex networks all put limitations on SET amplification.

My 8watts 300B SET plays on not even horn and not even efficient speakers (marvelous 88dB XTZ Master M2 speakers to hear or have), and yet sounds loud enough. Imagine now with efficient speakers!!!

'Sounds loud enough' is exactly the right term but for the wrong reason! The reason it 'sounds' loud enough is due to distortion. If you were to put the very same amp on a horn system, it would not 'sound' as loud until it was actually playing a lot louder, due to the fact that on a horn system there would be less distortion and so it would not 'sound' as loud.

This is because the ear converts distortion into tonality and in addition, uses higher ordered harmonics to calculate sound pressure. If the system has excessive higher ordered harmonics, it will 'sound' louder than it actually is. A sound pressure meter sorts this sort of thing out really quick! If you have excessive distortion, 90 db might 'sound' pretty loud since the ear's sense of sound pressure will be skewed; if the distortion is absent, 100 db (10x louder) might not sound any louder!

I recently swapped out my old EML mesh plate 45s for a new pair of their mesh 2A3s. I decided to go with 2A3s because that's what the ASL Tulip is really designed for. I was concerned that I would lose that 45 "magic", though.

After breaking in, the 2A3s have the magic, along with more "authority". The increase in power is probably 1 watt, or less, but I do get a sense of more headroom, a little more ease on the peaks.

If they really were type 45s, your output power is likely tripled. 45s only make about 0.75 watts or so single-ended. A 2A3 can do 3-5 watts.