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

Before I do that, I would love to consider several things:

#1 independent wired to the listening room. You might already did it! A great step IMO. If you like to go further, make it two. One for analog, and one for digital.

#2 clean power. EMI/RF problems sometimes are real problems for some people.

#3 room treatment. We, I mean, I listen to the room sounds first, then the other things in the system.

#4 like @audioman58 said. I sometimes like listening some classical, big sound stage, huge dynamic, etc. 300b or those 2w/8w amp really can get them there? I tried the "two years waiting" amp, I like it very much. But, some music want more.

 

 

Try something different like the 211 tube ,or 845   More then enough power and sound very nice 

https://caryaudio.com/products/cad-805rs/

a dedicated line yes awg 10 if possible , and as I did 4 wire one a common ground 

the other ground a isolated ground in its separate path connected to its own grid to ground more monies but worth it you don’t need to isolate the digital after this .

buy a very good Ethernet switch , depending on your budget the   SW8  only $600

or top of the line  innuos $3700. Depending on your dac and quality of your audio system  what you can afford , the AC outlets buy quality Gold over Copper Furutech  or another name brand ,even Pangea $100 AC outlet very good . And on router for sure a 12v minimum 4 amp Linear Power Supply , any gsrbage wall warts need to go $5 junk noise makers , little green computer sells for $299 and never use stock power cords ,at minimum on the LPS power supply a Pangea Sig MK2  for example  I even put a synergistic purple fuse in the LPS as well as the upgraded Ethernet switch , each one  small but important  improvements ,

and Ethernet cables cannot be low end or your streaming will suffer, this too applies to the USB cable. Everything counts , I am still working on upgrades  last 

your dac , to me as the source how much can you spend $$. Myself semi retired have to save for more expensive items , the T+A 200 dac  I still have a few months to go to save , is imo and many others dacs we have compared it to directly in our multi state audio get together for its $7200 price a true bargain it beats anything under $15 k and more and has HQ player built into the platform to give you the ability to find tune this to your audio system ,to make it better still. 

I think the OP is mistakenly ascribing personality to the 45, 2A3 and 300B valves. What matters more is the circuit design and parts used. I have a 45 SET custom-built by Will Vincent (autospec) on an ST70 chassis that turned out beautiful! Plus a Japanese Sanei SA-560A 2A3 SET made with Tango iron. This I won at an eBay auction from a Japanese seller. It is the quality of the whole amplifier - the gestalt - that elevates the performance rather than the specific tube type!

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.