The EICO HF-81 is one of the all time best integrated tube amplifiers made, competing with far more costly amps!

 
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EICO HF-81:
Vintage Route


Shocked...

I guess that was the word that best described my reaction upon first powering up this old beast in my system...

By Kelly Holsten


Befuddlement


How could this unassuming little integrated tube amp from 1959 make my painstakingly assembled cast of modern separates sound like they were emitting a sonic connect-o-dot drawing of the musical event? OK, perhaps I am exaggerating a bit, but I would be lying if I didn't admit this amplifier could embarrass many well known sub-$2000 solid state amps (as well as more than a few tube compatriots).

The Preamble


Yes, like every loon, I had scoured the net for access to affordable tube gear. Although, I had a wonderful modified Cary SLP-70 tube preamp that I had been running with solid state (Mosfet B&K M200 Monoblocks) and various EL-34 push-pull ultralinear options, I really wanted to get an SE or full triode tube amp, or at least something with some finer pedigree; I had never really recovered from the exposure to the insanely musical single-ended CAD 300se 8 watt monoblocks I heard in 1990. To this day, it still remains the best "in store" equipment setup I have ever heard (actually an understatement; it remains one of the most musical, real sounding amps I have ever heard. Period).

I was looking into kits for various SE designs such as the AES SE-1 kit, the Wright Sound WLA-3.5, and I even cast a few longing glances at the Welborne Labs 2A3 designs(see footnote ). Of course, I was deluding myself. Unfortunately, when it came right down to it, I had less then $150 to spend on a $2000 idea...

At this stage, it looked like the vintage route might be an interesting alternative if I wanted something of fine quality. Amps from Dynaco, Fisher, Scott, EICO, Heathkit, and LEAK were floating around on the Internet in various states of (dis)repair.. For some reason, the EICO gear kept jumping out at me, burrowing into my skull; indeed, it was the little triode input, Williamson HF-81 PP integrated that managed to worm its way into my subconscious. I realized there was only one place left, a place where one must drop all pretense of taste, common sense, and reason. That's right, EBAY.


Reality Sets In

Ebay is the only place where one can bid and vie for ownership with the likes of NinjaMan, TOOBBALL, TraderVic, and JazzFool; to say this is a bit disconcerting and a cause for alarm is perhaps overstating it. I had already made the Ebay dive with the heavy first purchase of $480 for a little used Rega Planet. Regardless, seven days later I have an amp, an integrated one at that. But this is not just any integrated, it's the famed EICO HF-81, considered, online at least, to be an excellent underground classic, outperforming some of the other more well-known kits and classics.

I was lucky enough to have the seller only within a few hours of my home, so instead of adding on the shipping, I decided to add on the drive; besides, the owner actually had a little used shop called the Stereo Exchange, filled with other tube gear. How could I refuse?

The owner, Mike, turned out to be a great guy. The amp turned out to be a rust bucket! I was rather crestfallen. My wife appeared a bit gruntled by the whole situation and began eyeing a shiny, chrome, Cary Audio SLA-70 that appeared to be modified. I loved the look of the Cary and had wrestled with this amp back in its day; yes, it was a fine EL-34 amp, especially this one as it had the upgraded output transformers, triode switching, and oil filled coupling caps. It also had an $850 price tag. Besides, I had been this route and the vintage bug was clawing at me more than ever (or was it just sucking blood?)

But for some reason, I just couldn't shake the lowly EICO sitting there. Ole Mike was even nice enough to absolve me from any feeling that I "had" to buy it if I didn't want it. Ole Mike. Well, I at least wanted to give the poor beast a shot as I had read and looked into buying it for quite awhile now. I dragged the amp over to a rather bedraggled pair of Klipsch Heresy speakers and a cheap Denon CD player. I was not prepared for much; the speakers were a whopping six inches apart with the Denon sitting directly on top of them...not much hope here on any front. After placing the EICO on the Denon and hooking up the sorriest pair of off-white lamp cord speaker wire I have ever seen, plus a garden variety pair of interconnects, I hit play...

It was one of the K2 20 bit recordings featuring Ben Webster and Gerry Mulligan...

LORD!

It seemed as if Ben was trying to blow his horn right out of those nasty beat up Klipsch boxes! I was amazed at the naturalness of the sax! That breathy sound of Webster's sax was extremely life like. Several of the patrons stopped what they were doing and stood up, unable to continue without giving it the respect of their attention. Look, there was little soundstage or stereo separation/imaging since these speakers were sitting side by side, but the tonal quality was all there and more. This little unit had some serious magic. Even ole Mike was a bit taken aback.

I pretty much decided then and there, I had to have this amp...


Home is where the EICO is...

When I first plugged this vintage beast into my girlfriend's system it looked quite a bit different then what you see here. Every panel was removed revealing perhaps the most homely chassis you have ever seen! The nude EICO HF-81 looked for all the World like a elementary school electronics project gone awry. All the panels were getting a going over (documented in pt II). Well, the lowly EICO might have looked rather homely, but homely had nothing to do with the sound coming from this vintage Williamson integrated; I literally could not BELIEVE the sound! If I thought it was good at the shop, then I would have to magnify that impression ten-fold once inserted in this properly set up system with a Rega Planet as source, Transparent wire and some surprising Polk RT5 monitors on sand-filled 24" stands (the Polk RT5 is a big surprise as well - The raves about this one are correct - great little speaker used for $150 or so..who would have ever thought.....Polk?)

...continued  Pt II: The Truth about Nevr-Dull


* FOOTNOTE: Ironically enough, I did end up with the Welborne Labs 2A3 Moondog Monoblocks

If you have any questions or comments concerning the EICO HF-81, please drop me an email:

Send to:
eico_hf81@earthlink.net

 

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EICO HF-81 Specifications
    

integrated amp
@14 watts RMS
all tube
twin tube rectifiers
triode wired to output section
williamson circuit


tubes
12AX7(4)
12AU7(2)
EL-84(4)
EZ81(2 Rectifier)

summary

This damn thing does not sound anthing like it should; it's just too good! I have not heard this much bloom, soundstage, naturalness, and soul from anything less than $1200... maybe more! The big name drones need to study up...Can $100 really buy this much soul?


Hover below and right click;
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Right Click and SAVE TARGET to Download 258K Schematic


PRICING

The main source for the EICO HF-81 was the lowly flea market and occsasional yard sale. This is where the "steals" took place. This is ALSO before people started realizing how GREAT this amp is; now the main source is Ebay, where you will find them turning up every now and then. There was a rumor that some loon in the tube land of the Far East was buying up cheap EICO 81s and selling them for three times the price!

Well, you can still find them on Ebay for a deal, but these are less than steller appearance units. They were prone to some rust on the transformers with a bit of discoloration and pitting of the chassis as well. Finding one in 9/10 condition is not too common anymore. Also, units with Mullards and a better tube selection go for much higher as these tubes are definite plus!

Untested w/out tubes: $100-150
Normal Range: $150-375
($375 for perfect w/ great tubes)

kh


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See EICO HF-81 Tube ID and Hookup diagrams
HF-81 Tube Layout and hookup





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