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

Have you considered Lab12 Integre 4 MKII?

Uses 4 KT170s. I love it so much and IMO as good as the much more expensive Jadis I70. Incredibly realistic timbre and bass quality. Vocals sound heavenly. I have one paired with Lab12 Dac1 Reference simply have no more desire to upgrade my DAC and Amp. 

Make sure you get the MKII version that comes with KT170s. The original uses KT150s. I actually tried my MKII with KT150s as well and vastly preferred KT170. KT170 sounds fuller, more holographic, and have slightly softer edge compared to KT150. 

Two of my friends have speakers with similar efficiencies. Coincidently both have 8 wpc.

Listening, very nice except I think they are both under-powered for instantaneous peaks, strong bass

Does someone make a bridgeable version, get two, use as monoblocks, get 16 wpc?   

 

auroravengeance:  The Lab12 looks nice.  I wouldn't know how the sound and dynamics compare with the three tubes I have mentioned.  Would love more input about the KT170's in the context of the others. Looks very nice and good price.

 

@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.