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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

Showing 1 response by larryi

larryi
3,765 posts
 

I like low-powered tube amps of all designs--pushpull, SET and OTL--so I am not so wedded to a particular design.  As jasonbourne71 stated, it is the particular design and parts used that matter most.  In particular, the output transformers and interstate transformers (if used) that matter a lot.  

I do have some tube preferences (meaning I've heard a number of good amps made with a particular tube type), but it is not absolute such that I universally prefer something made with that type of tube over others. 

Of the three small triodes mentioned, I tend to most like the 45 as long as it is used with suitable speakers.  I own a parallel 2a3 amp that I used with 99 db/w efficient speakers and a 45 pushpull amp (both have sufficient power for my purposes, but then again, I don't play the system very loudly.  I currently run a pushpull 349 amp (5.5 watts per channel) that I like a lot.  I tend to prefer the 45, 2a3, 300b over the larger transmitting-tube SET amps (211, 845) although these can sound very good.  For pushpull amps, I also like a number of old and new designs that employ 6L6 and KT66 pentodes.  For really exotic tube types, I like the 350B, 349 (pentodes) and the 252 (triode somewhat like a 300b).

For the OP's 96-97 db/w speakers, it might be possible to use the three triodes mentioned (particularly the 300b), as long as the owner is willing to accept some restriction on very high volume listening.  I personally feel that some compromise in that area is worth it.  For a safer bet on compatibility, something in the 40 watt range should be sufficient.  

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