I do not think that it is a mater of the output tube. Yes, the 300B is crappy tube but it is too easy to blame the under-performing tube. I would say that in the situation that Scott is experiencing the problem is not with his amplifier but in the ideological place that his amplifier ocupates in context of his installation and with the assessment techniques he uses in his reasoning-causing audio judgments.
What I mean is the Scott (or most of the people who believe that they “do audio” at that mater) asked pretty much the question about nothing and the question that has no relation to practical audio. The fact the Scott used the words that audio people can understand (horns, SET, cables elevators, etc…) does not necessary make his understanding of his own question. I do not knock to the Scott’s door but let look what the conversation was all about. Scott completely voluntary accepted an amplifier that somebody told him was a SET amplifier. With the same success someone would tell him that it was an amplifier that user the cold fusion…. How the hell the DRD-300B’s sound similar to what SET should sound I do not know. I also do not know where Scott found those “wonderful nuance, subtley, harmonic richness, and tonality” into the sound of THAT SET. What motivated Scott to use that Welborne Labs DRD-300B only god knows, probably he found it in garbage; he should put it back there… Now let rephrase the Scott’s qestion:
“The past 6 - 8 months I have been living with very efficient speakers (~ 109dB/m/w) driven by an amplifier that I have no idea how it performs. The amps use 300B output tubes for about 7 wpc. On paper, this should be a match made in heaven. In fact, the combination is capable of many things that my idiots-friends form AA taught me it would. It is really pleasing, especially on simple or crappy. Except for one thing – I do not know what it is but let me I call it dynamic. I am not referring to loudness. It can deliver more undistorted volume than I care to listen to. I'm referring to other set of properties that my friend form Audiogon told me about. If you go to the symphony, or live blues, than you know what I am talking about. Next week I'm taking delivery of a 90wpc PP amp, to audition in place of my current cold fusion amplifier. I need an amp that can maintain the purity of tone and harmonic texture that I head the SET might have, while delivering more corrupted voltage into my big and heavy bass drivers that with higher voltage applied to them discontinue to be a direct radiators and become horns.”
Well, the problem is certainly not with Scott but with the general mental approach of audiophiles to their playback. Would Scott be a DIY person (the moronic people that I really cant stand) or buying ready-to-go-audio he never identified for himself the fact the he was using a fundamentally fatly amplifier. So, where the “SET qualities” come to the Scott live: from his own experience or from his repeating the rumors of others? The only advise I can give to Scott, or to anything else at this mater would be forget what he believe he “know” about the amplifiers and do not even to talk about amsp with anybody. Listen an amp and decide for yourself what the amp does wrong. Then, ONLY THEN, after identifying what was wrong, make any move or conclusion. However, this time the conclusion would be about Scott’s own observations but not about the picking and embracing the idiotic rumors of the Morons which whom he is accustomed to socialize in audio.
As I said in “My Playback Rules” section of my site there are very few properly performing SETs out there. SET with all it’s appearing simplicity is the most complicated amplifier if the proper objectives are in aim. The dam industry and the foolish DIYers brew SETs but they do not get the purpose of making an amplifier is not to arrange the electronic parts in a orderly fashion and is not to apply the dead topological concepts - doing this one can accomplish a properly operating but not performing amp. The purpose of making an amplifier is to get out of it the proper Sound. Most of those people out there do not manufacture Sound but juts products and the result of own egos. When you talk with them they talk about this the advances in different topologies but the would never show or even imply Sound that indicate that they looked for it. All those “electricianing” produce brainless equipment - which if 99.9999% of all audio out there.
Yes, there are very few interesting tube that work successfully in SET configurations, there are very few interesting sounding drivers (the most important), there are fundamental disability of SETs working in full range (here is why SET should be multiamped) and there are many other complication with SETs. Still the biggest problems are not with the SET’s mentioned or not mentioned difficulties but with the people who use/make them. As I am very convinced that in a hands of a person who casers and understand how a playback should Sound even a 300B amp would sound appropriately. Unfortunately the majority of the SETs out there do not sound as their designer/builders even tried to get anything out them other then a correct plate voltage… So, what would be the conclusion of using a dead SET: to get a 90W mastodon?
Yeh, you’re right!
So far the Scott’s frustration do not sound different for me then a situation when he went to a fast food restaurant and was server with kept without frizzier 4 month old burger. Then Scott is eating the burger and begins to spread the pitching about the benefits of vegetarianism…
Still, the problem is not that Scott (and others) needs to change his current SET to the real one. What Scott needs to change is his ways how the audio problems should be approached, interpreted and resoled. Without it Scott will next month engaged in a new round of “inspiring audio frustrations…”
Romy the Cat
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche