Famous Direct Heated Triodes (DHT's) and the Unknown

Monsieurs Slagle and Jackson

Although the legend of the DHT tubes like the 300B, 2A3 and 45 got me into low powered amplifiers these Holy Grail tubes did not continue to hold my attention after a decade or so. It did however open the door to appreciating other low power, direct heated tubes. After hoarding a stock of NOS tubes while trying new production versions, which were often unreliable, it was time to look further. Before powering up a fleet of collectable tubes was the question: "Is it worth a thermal cycle on the tubes for a quick listen?" This is not the way. The enjoyment of music is the pursuit not materialistic and possessive concerns. After years of foraging in the mire for the same truffles everybody wants it became clear that the mind set of NOS tube acquisition was more about curation, trophy collection and possibly fetish than performance. Fact is tubes do not need to be expensive to sound good. Yay, I blaspheme.

Across the industry DHT landmark tubes like the 300B not only dominate - they rule consumers and often do so poorly. The majority of products are cashing in on the publicized trend leaving the consumer slowly to discover, sometimes over years, that the products they purchased, be it amps or tubes, are not at all what they hoped. The US military abandoned tons of vintage PA gear in the wake of post WWII occupation. Intelligent, sensitive ears salvaged and discovered the treats therein and created the seeds of legend with these discoveries. Yet this does not mean there are not others of equal or greater sublimity, in fact it should excite the curious to know what else is out there. Western Electric can sound good but it can also suck. Yay, I blaspheme! Klangfilm, Seimens, EMT and Russian, etc... artifacts are pretty sweet as well. The Eurodyne is probably the finest small venue vintage speaker there is. Yay, I say even better than the 753c or 757a. GASP! Yay, I blaspheme thrice! May lightning strike me if it is not true!

The WE300B can be an excellent sounding tube but they have no monopoly on special sound and to make amps, and replica tubes of them, poorly undermines the expectations that have been set by their mythology. This unfortunately is the market trend. Marketing, as we know, is all about mythology.

It reminds me of motorcycles in the 80s. The Japanese were not yet making decent handling bikes and so the Europeans were the ones to have. The American BMW ads of the time had the slogan: "The Legendary Motorcycles of Bavaria". After I got tired of grinding cylinder heads on BMWs I got into the relatively unknown Italian bikes. After waiting for a buddy a mile or two past an off camber chicane I returned to find him struggling with his BMW in the mud. Once we got it back on the tarmac he said panting: "That is the last time I try to follow a hot Italian bike on a German Myth. We both smiled. Going fast through corners has little to do with ad copy in magazines.

Mercury vapor baby - its hard to beat.

The iconic labels of 300B, 2A3, 45, etc are just popular labels for what a good DHT can sound like. If this is true what then lies beyond the scope of an audio reviewer's limited vocabulary? If they are indeed closer to the divine glow of tubes and share their wisdom across the alter for us to be blessed with must they not disclose the tenets from which they mount their ideology? If another divine glow is found and they do not recognize it does it then not exist? Must we suffer excommunication in order to explore it? What other glows could their be? Ahem, well this is the question but first: "What is wrong with the average big name tube amp out there?"

The 300B is not an easy tube to get working economically and so many implement it with inadequate voltage swing and/or inadequate current and resulting issues - sucky slew rates. etc... Chop it and dice it how you want, unless there is a pentode in there its a three stage program. (a step up transformer input driven by a low impedance line stage is a stage, its just in a different chassis). It is better to have a well engineered and tastefully voiced amplifier with an unknown tube rather than the average 300B amp out there. Blasphemy #1. The output tubes makes less difference harmonically than the driver tube. Blasphemy #2. The circuit design itself has more to do with the sound than any of the parts and tubes are just parts. Blasphemy #3 Yay, I blaspheme thrice, twice! Clouds darken and high voltages range to find a way to rapture me back to the herd - unless it is true - and then there is nothing in front but freedom and fresh air.

The first crack in the mythical facade began when I heard an amplifier which was not anywhere near the divine glow and did not pay any tribute to it at all. It had none of the elements the lore decreed. It used two 25¢ UF4007 rectifiers in full wave with a π filter. It was indirectly heated, it used a common, high gain but wimpy mini tube driver (12AX7, 12AY7 or 5751) with its two sections paralleled cleverly to give it some grunt yet with nothing but a resistor as a plate load, the output tube was a pentode (6CA7, 6L6, 350B, EL-34, or KY-66) run in ultra linear mode. Worst of all - it intentionally used feedback and even had a selector knob for adding this profane corruption! The real problem with it was that it sounded good. Real, serious good. Thus did the candle's flame waver and the shadows on the cave's wall flutter and fail. Light could be seen from the mouth of the cave and soon after the sky and sunlight for the first time. It was not all about the output tube! The amplifier did have unusual implementations which helped it to be what it was but these can be discussed another time on request.

The creator of this amplifier was Dennis Boyle. He lived in an old movie theater full of vintage gear collected over his lifetime. He had been a successful industrial designer before he discovered one day that one audio device could sound different from another after which he lost everything and fell into habitation with aisles of industrial shelving full of carefully collected vintage audio gear. In this closed stack of a humanities museum he lived a solitary life.

Mercury vapor with a damper diode.

Old movie theaters are spooky. They are built for darkness, temporary illusion and the pleasure this provides. They harbor pigeons who leave it everywhere, coo and come flapping out of places least expected. The smell of their guano is sour and makes for headaches. Harvesting vintage gear from these places was like spelunking. It was dark, dirty work which had a bad feeling about it. I would never visit these places without the promise of cheap or free vintage gear and so it was only after Dennis moved out of his abandoned theater and into a metal warehouse, which could hold all of his plunder, that I began to visit him. There was a little mono system which played FM radio through a Scott tube tuner. It was the only system I ever saw him use and it was always quietly playing. He never showed it off or asked anyone to listen to it. It just sat in a stack, speaker, tuner, amp, on the floor against a wall in the warehouse. Dust covered shelves held gear piled beyond reach row after row. After collecting all of this treasure in junk yards, craig' list, military salvage, and endless internet searches, after decades of study and pursuing the rare and precious flotsam and jetsam in pursuit of magical audio properties this modern day tube shaman, self confined hermit monk of audio listened to nothing else. This amp he called the Ace.

I spent some time there on and off over years becoming fond of Ramble, the Timber Wolf. In greeting he would put his snout between my legs and lift me off the ground, easily. It was just an affectionate nudge on his part which instantly lifted my feet off the ground. The first time he greeted me thus I wound up on my hands and knees. Dennis just commented that Ramble did not take to people like that often. Point being that the sound of that amp went into my comparator database unconsciously. Over time I became less happy with most 300B amps I heard. When I hosted a demonstration of the Axiom 300B amplifier brought out from Florida to Texas. This was Dennis' and Bob Hoekstra's (Nascar Engine designer) all out pursuit of a 300B amp done right. It made abundantly clear the tube itself was never to blame for comprised performance but these amps were huge and stupid heavy. They required two men to carry each mono block. With gobs of custom iron, three tier stacked supplies, ten tubes per channel and metal Deco styling from Dennis they looked like something out of Metropolis. (A modern day version of a 300B done right might be Ale's foray into the fray which became quite an amplifier. Ale's 300B)

The Axiom had 20 tubes to ignite for a stereo listen, the Ace had 4. They had things in common however, they were both alive, muscular, ultra clear and still had the inner lifelike clarity that is was what tubes are all about and few deliver. The similarity in sound demanded attention. One was easily an everyman's amp while the other a statement piece and yet they both broke, without even noticing, many of the decrees, laws and tenets of magazine audio. My conclusion? Tubes are not the problem, it is the commercialism which surrounds them. The 300B and its kin are like Merlot - it can be good but usually it is not. Nothing wrong with the grape but its commercial appeal created commercialized production and its sea of mediocrity. Want something better than Merlot? Learn about other grapes and wines.

It is to this venue I extend an invitation. Let us enjoy a little freedom and fresh air away from the marketplace, the ad men's hypnotic distortion field and amplifiers built into MDF cabinets with vinyl veneer to make them look like wood while costing more than a car. If you have not figured it out by now there is no hot, admiring house wife ready to hang on your every word just because you bought the shiny thing in the advertisement. MDF is dust - toxic dust. Let's make real stuff out of real materials with real design work. This means opening the design criteria well beyond the 300Bs of the world and using our ears to determine the value of music. It is after all our ears we are trying to please is its not? This is the way.

An all DHT amp with tubes not so heavily publicized.