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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.

128x128pseudonym
atmasphere's avatar
atmasphere
11,621 posts
 

Technically capacitors give wider bandwidth but transformer put the same driver tube in more linear mode with less distortions.

This statement is incorrect. You can operate any tube using coupling capacitors just as linearly as using an interstage transformer.

OTOH the trick with transformer coupling is making sure that the input and output impedances match the transformer properly to maximize bandwidth and yet prevent distortion due to the process of what is known as 'ringing' (which is when the output has an insufficient load).

@charles1dad The issue with direct-coupling (Loftin-White) is that you can have signals that are below the LF bandwidth of the output transformer; this can cause saturation (distortion) of the transformer. You also need higher operating voltages to pull this off. If you choose your coupling caps carefully, you can reduce the LF saturation problem and of course the power supply voltage does not have to be so high. 

charles1dad's avatar
charles1dad
10,235 posts
 

@atmasphere 

I don't think so- for teh last 65 years audiophiles have been hearing this problem despite the measurement camp touting its all 'expectation bias'; IMO/IME the measurement guys that think this don't have the engineering knowledge to understand why its happening. This in particular with solid state since its inception

This is an astute observation. It has been my contention for quite some time that those with thorough engineering and science backgrounds are open minded and do not dismiss what listeners say they hear. Of course engineers and scientists use and rely heavily upon measurements. Yet they willingly concede measurements can’t (Yet) account for all that humans detect while listening.

 

It seems to me that those who have a lesser level of formal technical education/training are the self declared “objectivists “ who cling so tightly to only what can be test bench measured. Thus a narrow and rigid manner with regard to audio issues. To assert that anything that can’t be proven by current measurements standards is simply expectation bias is lame and foolish.

With human beings it seems that the more you actually know, you then are more aware of what you don’t know. This realization keeps one humble and enriches further curiosity and exploration. This is the antithesis of the know it all arrogance of  the staunch objectivist.

Charles

ffzz
26 posts
 

Even in the case of capacitor coupling, loading the driver tube with a choke instead of a resistor will sound better - more dynamic and immediate sounding. No escape from good irons!

SET amps are simple, yet there are many circuit design and part choices that affect sound.

atmasphere's avatar
atmasphere
11,621 posts
 

It has been my contention for quite some time that those with thorough engineering and science backgrounds are open minded and do not dismiss what listeners say they hear. Of course engineers and scientists use and rely heavily upon measurements. Yet they willingly concede measurements can’t (Yet) account for all that humans detect while listening.

@charles1dad back in the 1980s the bit in your last sentence was true. But since the newer analyzer tools have become available, no longer. I’ve noticed though that such has little impact since people doing measurements often don’t do enough or the right ones; manufacturers don’t always publish them and finally, there’s not enough education in the field to be able to interpret what the measurements imply.

But if the stars align then you can accurately predict how a circuit will sound, based entirely on the measurements.

Even in the case of capacitor coupling, loading the driver tube with a choke instead of a resistor will sound better - more dynamic and immediate sounding. No escape from good irons!

SET amps are simple, yet there are many circuit design and part choices that affect sound.

To the first sentence, I’ve not found that to be the case, although with any kind of inductive coupling good iron is essential! Choke coupling is mostly an excuse to use an expensive inductor when a good resistor will do as well with wider bandwidth. Put another way, if more time was spent optimizing the operating point of the tube and less on fancy inductors that wind up (if you see what I did there) being mostly for show and tell, the circuit would exhibit the same positive attributes.

Any circuit that is zero feedback will be affected by nearly everything in it since there is nothing to reject distortion, phase shift and the like. To this end, to avoid phase shift you need really wide bandwidth. To avoid distortion, you need good quality parts, each part of the circuit optimized for the operating point of the active device (since this issue applies to solid state circuits with zero feedback as well) and proper layout to avoid stability problems and noise pickup.

veerossi
145 posts
 
@calloway. I’ve been sitting on the fence for a while about the WE tubes.
I’m also using the ACME matched top shelf 300B and 805’s in my Line Magnetic LM805ia. I’ve been reading about these WE 300B tubes for a long time. In your opinion: Is the ACME to WE tube upgrade worth the $cost? Was it a: "I should have done this a long time ago" or "Meh, they're a little better than the ACME's"?
 

 

 
calloway

867 posts

My SET monoblocks use 300B as the driver tubes. I have used Psvane ACME 300B and the new WE 300 B tubes. the WE tubes are better but you have to let them burn in for about 300 hrs before they reach their best.I use 845 tubes as my output tubes and use Psvane ACME 845s their also

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