August 2006

New Adventures In High Efficiency
Article By Scott Faller

  No doubt you are wondering what the heck this is all about. Well, let me tell you a story. Don't worry, it's short and do my best to stay on topic.

A long time ago in a far away land in a far away land, Lee de Forest, while dancing around the patent for the Fleming Valve (amongst others), demonstrated what was considered the first amplifier (see appendix 1 below). Lee, while showing his rudimentary amplifier to American Telephone and Telegraph, unknowingly helped to usher in the dawn of the Electronics Age. By 1920, the great monopoly (RCA) began mass producing electron tubes in part by planning for the introduction of 'radio' to the American public. At nearly the same time, early recording pioneers like Edison were running a parallel path. By developing a reliable means of playing recorded music, they captured the world's attention with the Victrola and the early shellac records.

Countless refinements have been made over the last century in reproduced music. Our goal as hardcore audiophiles is to achieve playback quality that comes as close as possible to faithfully reproduce the original performance. Herein lays the issue that will likely never be resolved. Which means of source recording, amplification and acoustic transducers will most faithfully reproduce a recorded event? 

While the objectivists (mainly) look at specifications and rely on flat frequency response to decide their audible fate, subjectivists like me, rely on our ears to tell us what sounds more 'real'. We subjectivists could care less how a product measures. Our only concern is that piano sounds like a piano, a woman's voice sounds like a woman's voice and so on. This reproduction must include the correct harmonic overtones for without, music will sound dull, dry, lifeless and artificial. If you are reading into that statement, you can see exactly where I'm headed. I use vacuum tubes for amplification. But it gets even worse than that. I use single ended triodes and high efficiency speakers. I abandoned high power solid state gear and low efficiency speakers a number of years ago. I've even turned my back on high powered push pull tube amps even though there are plenty of good stories to tell there too.

See, after playing with loads of high powered amps and low efficiency speaker setups, I always found myself longing for something different. My musical needs were never fully met. Sure, I've had some pretty decent sounding rigs over the years but none of them could match the accuracy of my single ended, high efficiency set up. For me it's all about the timbre and dynamics of the sound. If you can't get that right, you may as well be listening to a Bose system.

I've made it a point to always let you know what my reference system is in all of my articles. I feel that's really important. It's the only way that you can judge for yourself if you think my articles might actually be useful in some minor context. One of the other reasons is to help champion what I feel is (simply put) the best sound on the planet, single ended triodes and high efficiency speakers.

If you've read my works before, you know I do SET's and single drivers a little different. Rather than letting my Lowther PM2A's in the Medallion cabinets try to run full range, I play off their absolute best strengths, from (about) 100Hz and up. Below that 100Hz cutoff, I use a pair of vintage 15-inch Goodman woofers. I guess most people would call them subwoofers today but they are really just plain old woofers. These things sit at just over 103dB/W/m efficient. I've got my pair stuffed in the corner in nearly 5 cubic foot boxes that are aperiodic loaded. When all is said and done, these ultra cool woofers go all the way down to the mid to high 20's. The optimal issue here is that the Goodman's paper cones are super stiff and ultra-light. That means the timbre of the music produced by these woofers matches that of the Lowther PM2A's (nearly) perfectly.

The crossover from the Goodman's to the Lowthers is seamless. You can't audibly tell where the woofer stops and the Lowthers start. This is absolutely crucial to faithful reproduction of music. Too many times I've heard speakers that use passive crossovers that try to match incompatible drivers (timbre-wise). As you play music that runs through the crossover region, you can audibly hear the timbre of the instrument change. I've even heard this on some of the world's most expensive speakers, the Dynaudio Evidence Master speakers. Once you know what to listen for, you grow to despise passive crossovers not just for their lossey attributes but for the way they can destroy timbre and literally suck the life giving dynamics from my music.

This is one of the main reasons I use an active crossover. I've been bi and tri amping since the 70's. I was doing this before I fully understood speaker and crossover design. I only knew it sounded better so that's what I did. Over the years I've owned some pretty cool active crossovers. Now I'm down to a pair, my Pioneer SF-850 and my Audio Research (tubed) EC-3. Both of which I've restored (and modified).

So, just what the heck does all of this have to do with anything? Well, I guess more than anything, I'm just stating my biases. I want to be clear and concise about it so that when you grace me by reading what I've written, you know exactly where I'm coming from. Since I fell off the single-ended and Hi-E wagon some time back, it seems like the logical thing to do. To give you an idea how bad I've been bitten by the SET and Hi-E bug, I just tore down a damned fine sounding high powered tube system because I never listen to it anymore. The other reason for writing this is to introduce a new series of articles I plan on writing. Obviously they are named New Adventures in High Efficiency. In this series of articles I will focus solely on low and lower powered amplification and high efficiency speakers.

Ultimately, I'd like to be the tipping point for those of you on the edge who are teetering. Low power and Hi-E can sound significantly better than the traditional high power route so many take. Granted, high efficiency can be a bit tricky at times but when it's implemented correctly, it can't be beat. But that's just my opinion. More and more tube friendly, high efficiency speakers are hitting the market (think high Guassian strength rather than just efficiency points). Though still lagging compared to the usual array of monkey coffins, the past five years have shown nice strides by many different companies and DIYers.

So if you are a manufacturer of low powered amps or high efficiency speakers, you can likely expect a call from me.

(1) History informs us that Lee de Forest, though considered and named The Father of Radio, actually stole the "spade detector" design from the Fessenden Labs in 1903. de Forest further refined the concept and eventually promoted his very basic amplifier and the idea of multi-point broadcasting to AT&T in 1911 who promptly bought the patent rights.

References and a little light reading:
a. http://inventors.about.com/od/uvstartinventions/a/Vacuum_tube.htm
b. http://www.radio-electronics.com/info/radio_history/valve/hov.php
c. http://history.acusd.edu/gen/recording/radio.html