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The 300B World

Disclosure:  I am not new to Aric Audio, but I am new to the 300B.

 

I took delivery of my Aric Audio 300B PSET a couple of months ago. Since then, every listening hour has been different than it would have been were I new to both. I want to know who is responsible for what I'm hearing. So, the overriding question every observation is passed through is simply "Was that the 300B or was that the 'Aric Audio Heft'?" Over the years I have purchased a number of different amps and preamps from Aric and have come to identify certain characteristics that can be expected from all of his builds. That's why I keep going back. Examples include the "dead black" background, the solid signal strength delivered by his preamps, the ease with which the soundstage can be mapped, and the raw power resulting from the overbuilt approach he takes in his design work: "The Aric Audio Heft." Knowing what I would get from any Aric Audio amp is instrumental in being able to appreciate the magic of the "show off tube." 

 

I've heard it said that people who go to the 300B never really come back and I've been intrigued by that ever since. It invites critical listening across the broadest spectrum of music one can tolerate. It's here that observations are bagged and tagged, the first being the kind of music I listen to matters much less because I find myself listening differently and hearing so much more. One of my favorites is the leading edge of the lower frequencies and the way every beat reminds me that I'm listening to a 300B. The way I would characterize the sound profile would be to say it's as if the veil has finally been lifted and the distance between the performance and my listening chair closed. You know it immediately even if you can't quite define it yet and it commands your attention.

 

For some reason I'm surprised by how closely the tonal qualities of SET and PSET modes align. Somehow, I thought there would be more of a "sonic cost" for that extra power. I'm still cautious here though because the quad of tubes I'm using for PSET mode are not topflight tubes. So, the final analysis will have to wait until I can level the playing field. In SET mode I'm listening to a pair of Gold Lions, which I consider to be at least among the heavyweights. The question I'm presently grappling with is which tubes come next? I've done my due diligence researching the various offerings and think it will be a quad of Emission Labs XLS 300Bs. Any input around your experience with 300B tubes I would welcome. Yes, I have my wish list that starts with the Western Electrics (which I'm sure I'll own one day) but the guidance I'm seeking here is the step between now and then. What would be a suitable tube to take an already remarkable experience to a whole new level? Conversely, are there tubes that I should simply stay away from? My thanks to all. Happy listening.

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atmasphere's avatar
atmasphere
11,856 posts
 

Stereophile recently reviewed Klipsch La Scalas and measured B-weighted sensitivity of 101/2.83V/m.  The impedance dropped briefly to 4 ohms at 70 Hz, 335 Hz, and at length above 10k Hz.  Would a 300B amp be capable of driving these speakers?

@tomcy6 Yes. I recommend the 8 Ohm tap. You'll need a sub to be convincing (IMO) since the speaker rolls off sharply  below 50Hz.

So what makes 300b so special?

Nothing, other than it was one of the first power tubes used for SETs when they made a comeback in the early 1990s (back then it it was them or the 211...). By the late 1990s, the 2A3 had eclipsed the 300b, which in turn by the mid 2000s was replaced by the type 45.

But there really isn't any difference in the performance/sound of these tubes other than output power. The reason the smaller tubes sound better is the smaller output transformers, usually due to wider bandwidth.

In any case you need a speaker with enough efficiency to take advantage of that power. The Klipsch La Scala has a good functional minimum for use with a 300b at 101dB in most rooms. Unless you are in a small listening environment, speakers with less efficiency will cause the amp to make too much power (and distortion) to really appreciate what its about.

charles1dad's avatar
charles1dad
10,250 posts
 

@emergingsoul

So what makes 300b so special?

It is strictly a matter of perspective and sonic objectives. I believe that a talented and experienced amplifier designer/builder is capable of producing excellent sound quality with virtually any output tube.
 

It’s immensely subjective as to preference of individual listeners. I’ve heard excellent sound from numerous varieties of tube amplifiers.

Yet, for my taste, desires and goals the 300b is a superb choice. This assumes a serious implementation and build effort. If this criteria is met, the sonic and musical production can be genuinely great. Tone, timbre, harmonic overtone preservation, musical flow and pace can all be superbly rendered.

It has the capability to provide an exceptionally emotionally involving performance that is all inclusive and immersive. I can only attest to my direct listening experience. This is what the 300b has unfailingly done for me. A magnificent tube to utilize if handled by highly gifted hands.

Charles

larryi
4,054 posts
 

I find that there are differences in the sound of 300b, 2a3 and 45 tubes based on hearing many different amps employing these tubes.  In particular, I've heard amps built by one builder that employs similar designs using these tubes, including the same output transformers (pushpull amp using vintage transformers).  To me, the 2a3 has the clearest, most detailed, sound, and is leaner sounding than the other two.  The 300b is lush sounding and has a bump up in the upper bass and lower midrange (which I sort of like), but, it is a touch "mushy" sounding (lacking in clarity) and is dynamically soft and polite compared to the other two.  I like the 45 for its tight bass, reasonably warm but still clear sound and decent dynamics.  It is sort of the momma bear in the Goldilocks story.  All three can sound great and can sort of flip this generalization, depending on the specific implementation.  The 300b does offer a bit more power.

I own a pushpull 45 amp and a PSET 2a3 amp.  In my current setup, my only use of any of these three types is quite whacky--I use two 300b tubes as rectifiers in the power supply of my phono stage.  The amp in my system is pushpull and utilizes Western Electric 349 output tubes (If you think 300b's are expensive, try finding even used 349 tubes and see what they cost).

atmasphere's avatar
atmasphere
11,856 posts
 

I find that there are differences in the sound of 300b, 2a3 and 45 tubes based on hearing many different amps employing these tubes. 

@larryi 

I think you'll find that the differences you hear have more to do with who designed and built the output transformers than anything else. How well the tube works with the transformer; how well the driver circuit and voltage amplifier circuits work all affect the sound. So it seems unlikely that anyone might be able to describe the sound of the different tubes given those variables!

johnk's avatar
johnk
1,975 posts
 

A large difference in the power output of those SET tubes 45 about 1.5 watts, 2a3 about 2-3 watts, 300b about 8 watts. This you will hear if running high eff loudspeakers but transformers and overall design matter much in SET.  I tend to use 300b but have owned almost all types.

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