EICO HF-81 integrated amplifier
The EICO HF-81 is simply a fantastic-sounding amplifier that, properly restored, can sound better than most any single-ended triode (SET) amp of similar power.
Strong words, I know, from this audio loon. But I am amazed at the level of performance this old stuff has. We know that recordings from the 1950s and '60s can sound spectacular. If the electronics gear back then could get so much into the recording, it makes sense that it can get it out on playback just as well.
The HF-81 has a cult following on the Internet. I got 1060 Google hits for "EICO HF-81," and the first one listed was Kelly Holsten's site. Holsten was so impressed with his HF-81 that he built this website to tell the world about how shockingly good it sounds. Holsten noted every step of his restoration, with trials and errors and parts substitutions galore. I don't recommend you do this unless you're willing to invest lots of time in learning the process and have the money to set up a fully equipped bench with repair manuals (the 1956 TT4 RCA Transmitting Tube Manual, etc.) and tons of parts.
But what drove Holsten to do this? What's the fuss really about?
The EICO HF-81
EICO, or the Electronics Instrument Company, sprang to life in 1945 as a manufacturer of test instruments in Brooklyn, New York, and later moved to Long Island City. They began producing home audio components in the mid to late 1950s, as high-quality sound reproduction morphed from movie theaters into home radio into standalone sound systems designed to simulate live musicians performing in your living room.
Remember that episode of The Dick Van Dyke Show in which Jerry, the dentist who lived next door, was raving about his hi-fi? Dick was completely envious, and Laura thought both of them were nuts. The point is, in the 1960s hi-fi was a national phenomenon, and companies that already had the electronics know-how—such as EICO—were keen to enter this developing market.
The HF-81 was introduced in 1959 and marked the beginning of the stereo era. It's a low-powered amplifier by today's standards, but in its time, its 14Wpc mated well with the horn speakers of the late 1950s and early '60s. The HF-81 has two push-pull Williamson amplifier circuits and a stereo control center on a single chassis. Its design is based on the venerable 6BQ5/EL84 output tube, made famous by the British invasion and folks like George Harrison, who plugged his Gretsch Country Gentleman guitar into a Vox AC-30 amp using four EL84s. We were swept away by the music and the sound, and the world changed. That clear, punchy, driving guitar signature we now know so well was due to the linearity and clarity of the 6BQ5, which has become my favorite readily available output tube.
The HF-81 offers a full suite of controls, including Bass, Treble, Volume, and a clunky balance pot labeled Focus. The Focus pot is problematic—turn it all the way to the left or right and the other channel still bleeds through, and the sweeper contacts have not stood the test of time and must be cleaned or, better yet, rebuilt. These problems can be fully solved by yanking the pot and replacing it with a RadioShack job. The second control quirk is just stupid engineering: The HF-81's On/Off switch is also its treble control. Each time you turn off the HF-81, you lose your high-frequency setting. When I found a "neutral" setting, I marked the faceplate. The HF-81 is hard-core vintage.
The HF-81's low-level inputs are for tape head, magnetic phono cartridge, and microphone. In 1959, you had the option of outputting your open-reel tape heads directly to the preamplifier. The high-level inputs are Aux A and B, FM, AM, and FM Multiplex.
The versatile HF-81 could be used to convert a mono to a stereo system. Throwing a switch on the EICO allowed the HF-81 to drive its own amplifiers from one preamp section and an external mono amplifier from the other. The HF-81 also has a switch on the top of its chassis that can bridge the two amps to give 28W of mono output power. By today's minimalist standards, the HF-81 is a multitrick pony.
The most demanding loudspeaker I used to audition the EICO was the mbl 116 Radialstrahler. I was amazed the HF-81 could drive the mbls—it clipped relatively quickly but it sure sounded wonderful. While mbls are very insensitive, they offer a relatively flat impedance modulus that minimizes frequency aberrations when used with poorly damped (higher output impedance) tube amplifiers. The 116 is also the least fatiguing and most revealing loudspeaker I've ever heard in my home, and is my current reference (footnote 1). Plus, it looks cool and is a great visual contrast to vintage gear. In addition to the 82dB-sensitivity mbls, I used two different pairs of Bozak Concert Grands and Classic Audio's 97dB-sensitivity Studio Standard IIs for more concert-like listening levels. This gave me a broad range of speakers and, most important, impedance loads to present to the HF-81. (The speaker/amp interface is more important than the individual speaker or amp.) Cables were provided by Crystal Cable, TARA Labs, Kimber Kable, Nordost and Acoustic Research.
I placed my HF-81 on three Stillpoints (footnote 2) vibration-control cones, on a 2"-thick maple butcher block which was Tiptoed to the floor. I first heard the Stillpoints demonstrated at the 2005 Rocky Mountain Audio Fest, and was impressed with their patented ceramic-ball-and-Delrin-cup decoupling technology, which dissipates energy as vibrations pass through the ball and cup, thus reducing bass boom. The cones promise a lighter, airier sound when used under source components, amplifiers, and loudspeakers. More sets are on the way; I'll test them under other components for efficacy and synergy. The effects of the Stillpoints on the EICO HF-81 weren't subtle; there were substantial improvements in clarity and detail retrieval. I'm no big tweak freak, so this is a major recommendation; check them out.
Back in the 1960s, the EICO HF-81 was rated "excellent" by Saturday Review and "outstanding in quality and extremely versatile" by Hi-Fi Music at Home. Hirsch-Houck Labs, testing for High Fidelity, said it was a good value on its own merits, and a better one when price was considered.
First-time listeners will be taken aback by the inordinate amount of detail and frequency extension of this late-'50s design. To hear the punch and explosive impact of the HF-81, spin the overlooked Miles Davis masterpiece, A Tribute to Jack Johnson (remastered CD, Columbia/Legacy CK 93599). These sessions, recorded between February 18 and June 4, 1970, were an organically moving and evolving trip of jazz legends: Steve Grossman on saxophone, John McLaughlin on guitar, Herbie Hancock on organ, Michael Henderson on bass, and Billy Cobham on drums. On the opening track, "Right Off," McLaughlin's guitar explodes into the left channel. The EICO perfectly captured this brutal transient attack with aplomb, and as fast and as sharp as any Spectral amp. When Miles enters in center stage with a short blat, the EICO placed his horn smack dab between my speakers and slightly to the rear, in a reach-out-and-touch-it space all its own.
The HF-81 fed it all back to me—I heard the synergy, felt the music—just the way a single-ended amp delivers. It was amazing—and to ice the cake, the HF-81 didn't soften the bass or roll off the top. It was as if I'd taken a Krell, a Spectral, and an Ongaku amp, put them all in that transporter pod in The Fly, then thrown the switch and opened the second pod and, presto—the HF-81. The first day I heard one, I was up till the wee hours of the morning, losing my audio virginity.
The HF-81 excelled at capturing the space between the instruments. I'm not quite sure how to describe expertise in this, so I'll let a recording speak for me. "Roses," from Catie Curtis' excellent A Crash Course in Roses (CD, Rykodisc RCD 10478), can bring tears to your eyes if your system is up to the task. The song tells the story of moving from Ireland to America, against beautiful background soundscapes and atmospheres. The HF-81 retrieved this detail on a par with my Komuro 212, a 60Wpc SET amp that is a handmade masterpiece and for me, redefines the art of audio reproduction.
The little EICO could also capture delicacy and fragility within the size and scope of a large-scale performance—just like a high-powered amp. The Hen, from Respighi's The Birds, performed by Antal Dorati and the London Symphony Orchestra and recorded by Wilma Cozart and C. Robert Fine (CD, Mercury Living Presence 432 007-2), showcased the HF-81's ability to follow the melody as it dances from the strings to the flute to the oboe and back. Vintage amps are thought to be soft and blurry. Not the HF-81.
On Bob James' big-band masterpiece, Grand Piano Canyon (CD, Warner Bros. 26256-2), the HF-81 exploded with dynamic range equal to today's designs. James' piano was rendered perfectly against the bass line, with no smearing. Each instrument's harmonics were intact, blending together to form the correct tone that gives the listener the illusion of real individual instruments playing live together in the room. The HF-81's 14Wpc seemed more like 60Wpc—until it reached its clipping point, which was at about the same point as an 845 SET amp.
The EICO HF-81 performs best when mated to speakers that are easy or moderately easy to drive, and is readily available on eBay for $300–$800. Toss in a full restoration, and for well under $2000, the HF-81 can beat the pants off many amps and shame the SETs at their own game. I unconditionally recommend that you find an EICO HF-81, restore it, and hear for yourself what the fuss is all about.
Footnote 1: I'm now choosing among the 116, 111, and 101, to see which one will be my big "I made it through midlife crisis" audio purchase.
Footnote 2: See the Stillpoints website for information and dealer locations.