45 SET amp addiction


Staff member
I admit it, I have a strong addiction to 45 SET amps.

They can be simple and clean along the less-is-more tack, can be relatively hum free even with AC filament heat, and their antique simplicity means even a hacker like me can build one that sounds pretty good. And a 45 SET can sound SO good...

But 1.5w of output – what good is that?

My Altecs apparently eek out 100db with the first watt, which you’d think would make the 45 just fine, but I’ve always found that the 3w from a 2A3 is much more appropriate for my musical tastes, so the 45s usually go back on the shelf, and I live in 2A3 bliss.

But things change, and since a 45 hit is as close as flipping a few switches in my current amp, I keep going back for a fix, and I’m slipping, I’m becoming resigned to the fact that this tube is now ‘the shit’ for me.

Changes. I now use a separate pair of Altec 416As as helper woofers to the 604s; similar tone and speed with the modern shine of digital EQ and a nice SS amp. All the well integrated bass I need, while leaving the 604 mojo as-is and un-compromised in all their full-range analog glory, without the need to squeeze out that low bass.

So the 604s came out of the corners for even better imaging and the SET amp doesn’t need to plumb the deep bass depths anymore. Power is less of an issue and coupling caps, passive components and tubes can be more focused on optimizing the upper bass on up, especially the mid-range, tone, presence and imaging. All the stuff the 45 excels at.

It’s winter, we’re covid locked-down, no on-ice sports for the kids, no business travel, lots of time to relax, pour a dram and just listen for a change. Most of my listening these days is Americana, Blues and jazz, all stuff friendly to the 45, but the 2A3s were sounding pretty nice so I forget about the audio stuff and enjoyed.

On the weekend, I wanted to try some new things with the digital front-end; over-clock and push the player PC running HQplayer to get to PCM 16/44.1 > DSD256, ASDM7EC, poly-sinc-ext2 into the DSD direct DAC. This is purported to play dividends in the imaging, presence and smoothness – again, the stuff where the 45 excels. I was jonesing for a fix, so out with the 2A3s and in with the Tj-45s.



Staff member
I poked around a bit with some FLAC streaming off the internet, hear some Rick Rubin produced Cash which was just stunning, then slide into a tangent towards an old WAV rip I pretty much forgot I had – Jakob Dylan’s Seeing Things.


I don’t know what it is; Rubin’s sparse production, the recording, the digital changes, but damn! When did digital get this good! Dylan is right here in the room playing – big holographic image and depth, the walls are gone, I don’t know that I’ve ever heard a recorded guitar sound this ‘real’ in here before, I’m lost in this for the duration. How did I let this album go sitting on the server un-played for years?! This is SO good.

Then off to rediscover much of what I’ve listened to of late, more Cash, Willie Nelson, Emmylou Harris, Lucinda Williams, Townes Van Zandt, Steve Earle...It’s like a different ride, flying higher than the last one, I love it and I’m not getting off.

Yeah I know, it’s the damn 45s again. :)
now you're speaking my language! "HQplayer to get to PCM 16/44.1 > DSD256, ASDM7EC, poly-sinc-ext2" and a 45 tube... I had a pretty epic evening listening to digital last night. same thing... Old Flacs I hadn't listen to in forever. For me it was Garcia band official releases, and some bootlegs. I think I was able to listen to digital for so many years because I mostly used a 45 tube, it really helps bring out the strengths. And my Dac pumps out a little more volume than my TT. I Have some helper bass too, from a swarm, and have never heard my system so dialed in. Tonight I'm flipping records but happy to have had that experience.


Senior Nobody
Dam...I have resisted the 45 for years telling myself that 2a3 is good enough and more powerful.
Knowing how similar our systems and taste are... well your taunting me. 😐

Punker X

Junior Member
Been living with a Redboy SE 45 amp lusting for 2A3 for a few years now and just kind of wondered how it could get any better. Seem to sound good with any music I throw at them, Unless it is complex at insane volume. Think I'll go shopping for better tubes instead.
I admit it, I have a strong addiction to 45 SET amps. But 1.5w of output – what good is that?

Bill & Punker X, consider a pair of EML 45's. You will not be disappointed and they now have a 5 year warranty. You register the tubes on the EML site. I have the solid plates and they sound like they are putting out more than 1.5 watts. A few of us here bought them from EMISSION LABS (EML)

The owner of TJ Full Music passed away and AFIK EML is the only current new production 45. Allegedly, Psvane purchased the tooling from TJ. I'd like to see another new production 45.


Staff member
Now it's getting bad. :)

Went digging through the old stash and pulled out these Raytheon ST45s which I remembered measured strong and were cheap - you can still find a pair for $150 or so.


A little noise on start up but settled down and were quiet after a little hum-pot adjustment. These are light on their feet, detailed and accurate sounding. Still that big (real big) 45 image bubble, a little less of the old globe's hallucinogenic stuff but great instrument sound, scale, fingers on strings and wood - I need to dig into some Jazz!

Starting with another trip into the way-back corner of my wav rips and tried this; The John Abercrombie Quartet, Wait Till You See Her.


I bought this CD the night I saw John Abercrombie play at Shelly's Manne-Hole in New York. It was a good 10yrs ago and my memory of the evening is a little hazy, but hearing this tonight with these tubes has me right back there listening - SO life-like and full-scale - these really suit this music!
It is my favorite tube as well. I have a Yamamoto 45 amp and I have had others, in terms of sheer correctness mixed with a little magic, nothing beats 45 to my ears. And the Bass...sounds insane but the bass from a 45 tube is intoxicating
Has anyone here worked the curves of the 45 to see what the power out is with the grid V swinging to 0V?

That the 45 is rated for "2W" at 5% H2 distortion, suggests it might actually have some headroom above that before clipping. You might be getting a bit more power than you think, albeit at higher distortion, which if used just for peaks may not be an issue. This is also the case with the 2A3, which at classic operating points I quickly roughed out as 5W at 6% H2 distortion at clipping, though in practice I'd be surprised if that were achieved. I might revisit that one day.


Staff member
Exactly what I'm running right now..
I can see how this tube could be a place to just stop.

After the above Abercrombie CD, I played John Abercrombie’s Structures – an SACD rip. This is an out of print but amazing sounding Chesky release, apparently recorded with Abercrombie (guitar), Eddie Gomez (bass) and Gene Jackson (drums) playing live to a single mic at St. Peter’s Episcopal church in NYC.


Amazing dynamic swings from extreme intimacy with the quiet of brushed drums and subtle guitar tone to wow, that’s a bass; just charging and lighting up that space. This is the ultimate tube for this kind of music, it seems to do everything just right here and the experience of listening to this in a quiet room with the lights out is truly special – this is why I have all this stuff in the basement!

I don’t know, if you have the speakers (admittedly a very tough condition) to let flea power like this shine, it’s hard to imagine doing much better than this $150/pr tube with this music. My treasured WE & EML 300Bs aren’t this good, at least not in any amp I’ve heard them in.

But I know the 245 globes are even better than the Raytheons in some ways and the TJs are a better fit with more music, maybe even making this amp in 45 mode something I can live with long-term. And as Floriduhboy suggests, I have to hear EML 45s, maybe the best of the lot...

I know I’ll come to my senses here, play some Clash, Rush or Pink Floyd and shake off this monkey (I mean come on, they can barely manage 1.5w!) and go back to 2A3, but man, am I enjoying my time in this groove. And to be honest, I’m scared to pull out my favorite vinyl – that will have me in rehab. :)


Staff member
We have a lot in common Bill.... 45's and 604's
We certainly do Charles!

Would love to spend some time listening through your audio collection - so much interesting stuff there that is all right along the same path I ended up on.

In the 45 vein, my experience is limited to my simple WE417A>45 amp with James iron, I'd love to hear different takes on simple 45 circuits. I really liked the Yamamoto 45 I've heard on a few occasions but never got one home.

Looks like you have EMLs too - maybe my next stumble down this rabbit hole - what do you think of them?