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

@gregjacob I have not heard the tubes you mentioned, but I compared the Lab12 against some really good SS amps in 5 digits range like Esoteric Class A, Gryphon 300, Vitus Integrated and Aavik I-280.

I would say it has similar sound and refinement as Aavik I-280. Everything just sounds coherent and correct. It leans towards bright tonality with just a touch of warmth. With KT150s it sounds more aggressive and less warm, perhaps better for rock and metal, but I preferred KT170s for vocals by a mile. 

 

elliottbnewcombjr:  That would probably be the best way to go. However, I do know there are quite a few 300B mono blocks, but I've not seen a single example of the 45 and PX25 doing the same.  Those tubes get such high marks, it would seem like a good path, but I'm not an engineer.  The tube amp systems that run in the tens of thousands never employ them... There must be a reason.  I do know that some of these run hot, but that's speculation.

This thread has gone away from the low power SET which the OP asked about.  His speakers will be fine with 2 wpc or even 1.8 which is the normal output from a 45 SET.

I'm driving my 96dB speakers with 2 wpc and while I listen at moderate volumes, I watch movies at theatre level and I'm driving the fron speakers during movies with the 2 wpc amp.

Many of the suggestions in this thread are the push/pull design that he is trying to get away from in the Primaluna.  These higher power tube amps are needed for those people trying to use tube amps with the currently ubiquitous 88-92 dB sensitive speakers.

Jerry

Does it really matter though if the tube amp is low power SET or push/pull design as long it sounds good? I would keep an open mind. There are excellent push/pull design just as there are excellent SET design. If budget is not an issue, I would have recommended that the Silbatone SET amps to be considered. They are wonderful as well. I stand by my recommendation of Lab12 Integre 4 MKII, it really equals high-end amps in the $20000+ range. There are also other options like Leben CS-600 and Audio Note Cobra, but I think the Lab12 is the best in its class already.