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Published March 15, 2001

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Audio Electronic Supply AE-25 Super Amp

When Marc Mickelson asked me if I'd like to hear the Audio Electronic Supply AE-25 that he'd just finished reviewing for SoundStage!, I immediately answered yes. Already famous/notorious for its combination of low price and high performance, it was the darling of the Internet for a while. People were talking it up.

Dubbed the "Super Amp" by designer Dennis J. Had -- after his wife commented on the "super" sound he was getting out of it -- the AE-25 was available in a number of configurations. And now, six months or so later, it is available in several more. First off, it can be had in kit form ($1000) or pre-assembled ($1200). It can be configured for triode operation or ultralinear, and it can employ a wide range of power tubes -- everything from KT-88s to 5881s, KT-66s, EL34s, and KT-90s.

Since the introduction of the original Super Amp, Had has also designed two step-up models. The Super Amp Signature substitutes a pair of 6BQ5/EL84s for the basic model's 6CG7s as pentode current sources driving a pair of 6922 input tubes. As a result, the Signature puts out an extra 5Wpc for a whopping 30Wpc. The Super Amp DJH is a substantial upgrade from both the standard and the Signature versions. Its output power is 35Wpc in triode mode, utilizing KT-88s, EL34s or KT-90s, although one could also use KT-66s, 6L6s or even 6V6s. These lower-dissipation tubes will yield around 20--25 watts of output power. The DJH model has a larger power transformer, film-and-foil capacitors in the power supply, and a dual negative DC bias supply that incorporates a filter choke. The DC voltage supplied to the two 6922 drivers is dual-regulated for increased stability.

My review sample, however, is the basic, plain, vanilla AE-25 running in triode mode.

Art distils sensation and embodies it with enhanced meaning in memorable form

I asked Had what he had wanted to achieve in designing the AE-25. "Boiled down, I guess I wanted class-A triode sound with some horsepower," he said. "What I really had in mind was creating an amplifier that had single-ended triode midrange beauty and a push-pull amplifier's speaker-driving capability."

That design incorporates four triode/pentode output tubes driven by 6CG7-regulated 6922 input tubes. It runs cathode-bias class-A and employs no global feedback. There are no user adjustments. Biasing, no matter which output tube you choose, is automatic. Parts quality is very good and the build-quality (my review unit was factory constructed) is superb, with point-to-point wiring throughout and first rate fit'n'finish. It may not cost an arm and a leg, but the AE-25 is built to justify -- if not engender -- pride in ownership.

It’s a modest looking unit -- a pebbled black baked-enamel finish covers a low deck-style enclosure mounted on four squishy footers. Three transformers are arrayed in an arc across its rear, the center one proudly "nude," and the eight tubes rise from the front apron in two closed arcs behind a gold-lettered cursive "Super Amp." The front of the apron sports more gold lettering (the AES logo and "AE-25 Push-Pull Stereo Amplifier"), two switches (power and operate/standby) and a green power LED. The rear panel has two sets of solid-metal five-way binding posts, a pair of high-quality RCA inputs (XLRs are a $100 option), a phono-plug test-probe input, fuse holder, and an IEC mains receptacle. With its modest 14 5/8" by 12 1/2" footprint, it feels far heavier than its measured 31 pounds.

Expressing emotion in the form of art...

Hi-fi, as a hobby, has many houses. Your reaction to the AE-25 will depend upon which of them you inhabit. If you believe that the only purpose of an amplifier is to reproduce its input signal perfectly but at a greater amplitude, then it's not the amp for you. If you don't like the very idea of tubes, if you believe that tubes start burning out the day they're installed, this amp is not for you.

However, if you're comfortable holding the two contradictory concepts -- that tubes have a sound and that they reproduce the real experience of music in a very special way -- then the AE-25 is definitely the amp for you. Configured, as it is, to accommodate a wide range of output tubes, the AE-25 could be considered a celebration of tube sound. You can roll your own until you get the sound you want. (And if that very idea gives you the fantods, then the AE-25 is not the amp for you.)

Oh yeah. If you need a lot of power, then -- obviously -- a 15Wpc amplifier is not for you.

But if you think audio can be fun -- even when it's not perfect -- this amp is definitely playing your song. Fun is a word that just flat-out irritates some audiophiles. So is tube magic. But them's the words that come to mind.

Yes, tube magic is essentially a euphemism for euphonic distortion. So what? It meant that the AE-25 sounded sweet and liquid on top pretty much no matter what I fed it and, while I like linear measurements as much as the next guy, I'm not immune to being seduced by sheer beauty either.

Another consistent characteristic was the Super Amp's ability to soundstage. Wow! If your software has any soundstaging information at all, the AE-25 will make the most of it. This means that marginal recordings sound really special and really special recordings, such as Emmylou Harris' Red Dirt Girl [Nonesuch 79616-2], have a sense of space and air and sheer physical presence that borders on the scary.

The degree to which the amp exhibited these characteristics depended to a greater or lesser extent upon the tubes being used. For all around balance, including bass control, I'd go with the stock KT-88s, although as an audiophile weaned on a pair of Marantz 8Bs (I used one channel in each for serious separation), I have a weakness for the soft sensual sound of EL34s, so I logged a lot of hours on them as well. KT-90s made for an interesting change -- more like a current ultralinear amp (i.e., very straightforward) and less classically tube-y. (Which probably makes them the choice for those suspicious of phrases like tube magic).

Although the Super Amp can sound authoritative with the right speaker, you do have to exercise some care that you have the right speakers. Current-hungry designs, such as the Dynaudio Contour 1.3 Mk II, simply didn't get the oomph they require with the AE-25. The Soliloquy 5.0, on the other hand, sang beautifully in concert with the amplifier. That particular combination gave me goosebumps, especially on vocals of any sort, as well as chamber music.

A polite form of self-imposed torture, the concert

The Tallis Scholars' recording of Josquin's L'homme armé masses [Gimmell CDGM 019] sounded particularly yummy through the Soliloquy/AE-25 combination. Missa L'homme armé sexti toni spaces the four vocal ranges widely apart. This performance features an astonishing transparency. The altos float above the other parts as if nudging at the hall's ceiling. In the final Agnus Dei à 6, Josquin placed two joined canons in the upper ranges against a double cantus firmus in the bass -- one part singing it frontward and one backwards. The effect is hypnotic and startlingly modern -- it seems to look as much toward Steve Reich as toward Pope Gregory.

This is dense music with vocal lines lingering and twining amongst themselves. In the hands of lesser artists, it can sound as difficult as it actually is; however, the Tallis Scholars negotiate its trickiness with grace and an obvious love of the source material. Their performance is not just light, but suffused with light and lightness. The Soliloquy/Super Amp combo perfectly unveiled their sense of delight and illumination without even breathing hard.

The Polk RT 3000P, which combines a passive midrange/tweeter cabinet with a powered subwoofer section, also proved to be a fortuitous pairing with the AE-25. The Polk doesn't need a lot of power and -- at least as suggested by its performance with my Musical Fidelity Nu-Vista 300 -- doesn't respond well to a lot of power. But mated to the AE-25, it was something really special. The RT-3000P's dual, powered 8" woofers give it impressive and realistic bass, which mated beautifully with the sweet, controlled sound of its midrange/tweeter section driven by the Super Amp. This made an exploration of big orchestral music particularly thrilling.

But for meaty, beaty, big and bouncy audio thrills, nothing beats Wagner. I started on a morning regimen of the Ring as assayed by Solti et al [London OSA 1309/1508/1509/ 1604], which proved instructive on a variety of levels.

First, I couldn't get enough -- I polished it off in a week. I'd never expected a pace of an opera per day, but I didn't want to stop. The glorious cast and the spectacular playing were addictive, as was the phenomenal soundstaging. The orchestra was so obviously in the pit between the singers and myself, it was uncanny -- and spatial cues within the soundstage were detailed and specific. I thumbed through Culshaw's Ring Resounding while listening and, Sir John would be proud to know, all of the obsession and obsessing over minutia detailed in its pages were gloriously obvious on the record. What a great way to spend a week! (Although it did make for some interesting dreams -- I wonder if Wagner has a particular ability to short-circuit the conscious and head directly to the sub-conscious -- or was it just too much time sitting?)

Take thy beak from out my heart, and take thy form from off my door!

Super? I'll say. When you consider that, in kit form, this amplifier is extremely affordable -- and it doesn't really cost much more assembled -- its build and parts quality are extremely satisfying. And its sound, if you're willing to acknowledge that hi-fi components can have a sound, is seductive. I love it and recommend it highly to anyone searching for something to put the fun back into their audio hobby. It's got that tube magic in spades.

Just keep in mind that it does have a sound -- one I'd characterize as sweet, exciting and intensely satisfying -- and that, at 15Wpc, it requires the right pair of speakers to sound its best. But if you're willing to give it its due, it'll give you its best. And that is very, very good indeed.

...Wes Phillips
wes@onhifi.com

Audio Electronics Supply
111-A Woodwinds Industrial Court
Cary, NC 27511
Phone: (919) 460-6461
Fax: (919) 460-3828

E-mail: info@audioelectronicsupply.com
Website: www.audioelectronicsupply.com

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