SET amps and "efficient" speakers

When considering SET amps with 300B series tubes, what speakers pair well with them. I’m only asking out of curiosity after reading other forums where folks said they required “efficient” speakers beyond 92dB (!?). Horns? What models? What are the pros and cons? I think (dangerous!) it sounds like small venue acoustical, jazz, etc. (And no, I’m not about to give up my BHK 300s and Focal Supra No. 2s.)

Just trying to educate myself, so don’t waste your time unless you feel the need for a little fun.

All my best.


@BillT - I’m surprised I’m the first person responding to you on this, and I just responded to your vinyl setup post.

If you’re looking at 300B SET, chances are the power is somewhere between 8-10w/ch. While the thought of a speaker 92db might work, it will depend on the size of the room you are placing it in. Generally, I would think to pair the 300B amp with a speaker that has an enclosure or horn system that can extend to the low frequencies. This requires a rather large woofer, large cabinet, or large horn. Though the speakers are efficient, it needs the right air and reflex to get the best response. Case in point, I’ve used a few 300B SETs on a few speakers - Zu Soul Superfly, Lii Audio Crystal 10 in open baffles, and Quad 2805 (yes I’m serious) and while the gain wasn’t high enough for the Quad, they sounded best with them. Both the Zu and Lii are ~100db efficient, but the bass and mid bass were lacking as the cabinets were not sufficient enough to support.

The preamp matters a whole lot, too, in this case. You’ll want as good of a preamp as you would have in the quality of the 300B amp, if not better, and low watt amps tend to have preferences for preamps that have medium level gain.

Should you have gone this route and need thoughts on 300B tubes, I can do so - but that’s a whole different thread. :slight_smile:

I had a 300B-XLS SET amp output 22w with 90db PMC speakers and was sort of OK bass, but then got Harbeth and it was a waste of time. expensive, hot and ultimately pretty hopeless.

Thanks for the replies! Basically you guys are telling me to wait until after the pandemic and do some serious listening first, as this is not a easy path to take. Great care is apparently required to match all the components.

First there were valves. They were good, but expensive and low powered.
Then there was Class A solid state. It was not as good as valves.
So they improved Class A solid state and it became better than valves, but a few people preferred valves.
Then there was Class A/B solid state. It was not as good as Class A, but was more powerful and more efficient.
So they improved Class A/B solid state and it became better than Class A, but a few people still preferred Class A.
Then there was Class D solid state. It was not as good as Class A/B, but was more powerful and more efficient.
So they improved Class D solid state and it became better than Class A/B, but a few people still preferred Class A/B.

Sounds like an arms race! :smile:

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Pretty much. All this obsessing about SACD, it’s a generational thing, My kids are big into music and they’ve never heard of SACD. CD was something from their childhood, long discarded. My guess they will go through life never having heard of DSD either. The world moves on.

Because solid state made power cheap, and a class D makes it cheaper still, there was little need for highly sensitive speakers. So around 86db became the norm and high sensitive speakers became few and far between. They also tend to be quite expensive.

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i think obsessing is (some might say unfortunately) human nature…

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My audiophile failing is not being obsessive enough.

When I look at that valve amp I owned, and a bit of a mistake as well from the money side, I just put it down to a mid-life thing. I have no nostalgia for redundant technology from the past that is out-performed by modern technology at a fraction of the cost.


Maybe I’m approaching this completely backward: if an SET is the solution, then what is the question? In other words, for what type of music and room size would an SET with a properly matched speaker system be selected? If its a vocal, chamber music, small acoustic or jazz club setting, in a smallish space (?), then a small set of electrostatics with SS would give an alternate path?

BTW Steven, thats a great looking TT platform. Wall mount?

Hey stevensegal…

Hopefully you will have given your kids audiophile experiences going from
vinyl, cds and current digital music sources…

Years ago I read about a college kid who brought home some college buds
over Christmas. In the basement was his dad’s high end system of the 70’s.

His buds all they heard was ipod degraded music…

Needles to say …that bunch never left the basement as vinyl after vinyl
album was played and some repeatedly…for they had never heard anything
like that before…

Best wishes

Wonder what ever came of those guys …if they themselves
turned into audiophiles…

My kids use the main system (Wilson/Devialet), streaming to it from Spotify. My elder son has a large vinyl collection, an integrated amplifier and speakers and streaming via an Auralic Aries Mini I gave him. My younger son has a Naim MuSo Qb2. My wife has a Devialet Reactor and there is another one in the kitchen. So we have streaming and vinyl, but not a silver disc in sight, and there hasn’t been for at least 10 years.

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The role of an amplifier is to drive pair of speakers. It’\s not to decide what you listen to. If the amp cannot make the speakers work as they are meant to it’s the wrong amp.

That said, with a 300B, perhaps a pair of Tannoys or Audio Note, a pipe, a pair of slippers and a cup of cocoa.

The platform is from HiFi Racks - special order strengthened version. The previous deck was 38kg.

I run a Decware SE84UFO25 ( 2.3 watts ) into Avantgarde DUO Omegas ( 107 dB horns )
The SUB225 bass units have 200 watt plate amps ( 140 Hz on down )
I have no problems with any type of music at low listening levels or rocking out levels.

I run Decware SE84UFO3-25th Anniversary Mods Monoblocks with 92.5 db Decware HR-1 speakers. With the help of Decware preamps and the Decware ZROCK2 I have no problem playing any type of music I like at any volume I wish. I’ll never go back to solid state if I don’t have to! These are more like pseudo-triode single-ended amps as they use the 6P1P/EL84 tubes as output devices. And they do not have the same characteristics as 300B amps. . .very neutral and clear and tight clean bass.

I would have thought the larger models in the Klipsch heritage series (e.g., Cornwalls) would be a good match for low powered tube amps. After all, they were designed when tubes were the only option and jazz was what the cool kids listened to. I have not tried them with SETs but my second system has Klipsch Tangent 400s (a 3-way using the Heresy II drivers in a front-firing ported box of 1.5X the volume) which are 97 db/1W/1m and play loud with even a chip amp. A bargain for what they go for used.

With my SE84UFO 2.3 watt Decware amps and my 100 db, 16 ohm speakers, I can rip the house down. Seriously.
BTW–The 6P15P tubes are far better than EL84’s in this amp. Have you tried both, Lon?

Oh yes I’ve tried both. I buy my 6P15P* tubes from Steve–he tests them and matches them more closely than many sellers do, and they sound the best of all the variables I have tried (and there’s a mod he does that EL84 doesn’t take advantage of).

*I bought the 27th amp Steve ever built in '98 or so and that was before he did Revision A which was to make the amp use the 6P15P tube; I sent it back when he made that revision; it is still in use in Texas in a friend’s system.

Okay, so these are really more versatile then I originally thought and I need to keep plugging away with my research!

Ron, what speakers are you running? Approximate room size?