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Best Tube Amp for High Sensitivity Speakers: 45, PX25, or 300B?

I am looking to change / upgrade my tube amp.  I have a good, all-purpose Primaluna EVO 400.  It employs the EL34's and has a nice sound, especially in the ultralinear mode. Other components:  streaming from Innuos Zenith MKIII to Lampizator Atlantic DAC.  Everything playing through Daedalus floorstanding speakers with a 96-97dB sensitivity. Currently, my office / listening room is on the small side: 12'L x 16'W x 8' H, but I'm building a new listening room on our farm where I will later upgrade some components to fit a larger room.  Now, here are the tube amp options I am looking at:

Audion Silver Night PX25  8 Watts.  Very popular among some, touting a slightly more balanced, dynamic sound over the 300B.

Swissonor 45 SE  or  Tektron TK One 2A3 / 45 i   The 45 is the low wattage (2.5W) but sweet tone alternative. Considered by many to be one of the most musical out there. Of course, its low power makes it more restrictive, only efficient with high-sensitivity speakers and in more small-to-moderately-sized rooms.  It might be great in my current office but would have to work harder in a larger one later.

300B Integrated Amp, Make / Model not yet determined.  8-10 watts.  Of course, the 300B is making a big comeback and has wonderful characteristics, especially in the midrange and especially with certain genres of music such as acoustic, vocals, jazz, etc.  I heard one opinion from someone with a history of work in sound production, "The 300B is great if you just want to listen to a female vocalist with a guitar." One take on it.

Adherents of the PX25 and 45 tend to regard the 300B as a nice-but-limited cousin. I honestly have no experience with any of these three tubes.  I moved from SS to tube with the PrimaLuna, a well-built amp that I have increasingly felt carries some limitations that other tubes--more focused specifically on higher sensitivity speakers--would open up the sound in the lower frequencies and some tone qualities all around.

Any opinions would be welcome.

 

gregjacob
elliottbnewcombjr
5,116 posts
 

gregjacob OP

It is a great thread, so much info from others.

I needed 16 ohm taps, so I had limited choices. I have extremely efficient horns/15" woofers, historically happy with 30 wpc, so I never thought about more than 45wpc.

I never considered it when I bought my Cayin A88T, but it may be a good idea, whatever category you go for, to go for a bridgeable model, keeping the option for another in the future.

let us know what you end up choosing.

 

ltmandella's avatar
ltmandella
115 posts
 

There is a 300B based OTL amp available in kit form.  If you don't want to build it, announce on the manufacturer's forum that you would like someone to build it for you.  You will have to compensate the builder but it is the best 300B amp money can buy.

medium_grade
77 posts
 

Personally, I love my Elekit 8600 300B amp. Even if you get someone to build it for you, the price is fantastic and you won't have to wait nearly as long as you will for a new Decware amp 🤮

nrthomas2
32 posts
 

I love my Yamamoto 2A3. Hand crafted beauty with soul. Plenty of power with my 96dB speakers. There are 45 and 300B options as well.

markusthenaimnut's avatar
markusthenaimnut
353 posts
 

Great question - great idea for a thread.

I previously used a vintage (Cary Audio/Dennis Had designed) AES SE-1 300B stereo amp, from the ’90s. It sounded great and I loved it with my 93dB sensitive/efficent/whatever JBL studio monitors.

Then I had a chance to compare it to a pair of Alan Eaton 45 monoblocks, that put out somewhere around 1.5 watts. The Alan Eatons were better - deeper bass, clearer, lovely treble, richer tone, more beautiful sound. Note - this is in my room, with my listening preferences. I typically listen in the near field below 75dB, so I am just using a fraction of a watt. The Alan Eatons are simply coasting.

A couple months ago I also picked up a pair of Altec A7 Magnificents. ~96dB.

I learned about these amps on the Glow in the Dark audio website. I love that website for the photos, the writing, the descriptions of the various amps and tubes.

Also, as I have previously done, I humbling suggest you download a simple app for your smartphone so you can check what volume you normally listen at. I use decibel X-Pro. It was not expensive and works great. I use it frequently. No, it is not the best SPL meter in the world but it will tell you what you need to know.

Personally I think the 45 tube is where it’s at and these simple, simple circuits with minimal parts count and highly efficient speakers.

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