Ah, immediately spotted the Eico!
Reminds me of my lovely refurbished Eico HF81 that I sadly sold a while back. Boy I loved that amp!
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@MattHooper - ahh, "Matt", "Matt", "Matt"... you have triggered me!
I am a long, long, long time fan of things EICO. Literally grew up with the stuff.
The AF-4 (SE EL84, a budget product*) seen in the photo I posted has been in my family for its whole life (i.e., much of
my life), having belonged to one of my aunts (now deceased), who passed it along to me ca. 2007.
The HF-81 is a nice integrated amplifier. Your HF-81 looks like Kelly Holsten's! He was an early member of the Klipsch forums who talked up these fairly modest PP EL84 stereo amps. He was a fairly early website design guy, and his nice looking HF-81 page
started the rush (and price run-up) of these - let's be honest
- rather
homely-looking little amplifiers. They do clean up rather nicely, though, and his good photos of his nicely rehabbed amp were bait for the emerging
tubes 'n' horns market in the '90s.
The price spike in the HF-81's coffin (so to speak
) was a retro-review of a restored on in
Stereophile in 2006. The price of these fairly skyrocketed thereafter, and is still pretty high for a 12-ish wpc amplifier of modest construction values.
Good iron in the HF-81, though, which is probably (arguably) the amp's secret sauce.
If you spotted an EICO HF-81 at the local Goodwill, you'd think nothing of this plain-Jane integrated amplifier in its nondescript gray case. But if you kept on walking, you would have passed up one of the best-kept audio secrets of all time. The HF-81 hails from hi-fi's pioneer days, before...
www.stereophile.com
The one that Peter Brueninger reviewed had been restored by a then-revered
EICO-whisperer called Sam Kim.
@John Atkinson dutifully put the restored (retro-modded?) HF-81 through its paces.
In some respects, its objective performance is pretty good. In others... well...
But the fact remains that it is a reliable amplifier seven decades later with relatively minor attention, and
almost all** of its important bits are still readily available. Can't beat that with a stick!
One of my first significant eBAY purchases was a pretty nice HF-81 which I rehabbed myself. Mine's an early version, with OPT taps all of the way to
32 ohms(?!) -- it is roughly the same age as me. The
only issue with mine (other than its decidedly drab,
as-is cosmetics***) is a little bit of audible hum. So it goes for those of us with 100 dB-ish sensitive loudspeakers! One mW of signal at the loudspeaker is good for 70 dB SPL at 1 meter, you know?
Gary Kaufman
https://the-planet.org/, who has one that's dead silent, and I spent a Saturday afternoon tracking it down -- but never did. As my father pointed out to me many years ago, though, one of the problems with troubleshooting
somebody else's assembled kit is that it may have
never worked properly due to more or less subtle issues related to assembly. Sometimes, sadly, the best recourse is to strip the chassis and patiently re-assemble!
However, see my footnote*** below.
One known weak spot, especially in the cheaper EICO kits, was the use of barely adequate power transformers. This, coupled with typically higher mains voltage in the US in the modern era, puts the PTs at some risk. Heyboer in Michigan made the power transformer for the HF-81 (and possibly the OPTs as well?). They're still around, and, at least 15 or 20 years ago, were
more than happy to build a beefed-up variant of the
original PT by request for a very reasonable price. I had 'em do one for me many years ago, which I have in stock for replacement if (when) needed.
source:
https://www.audiosciencereview.com/...ow-wattage-amp-tube.40665/page-6#post-1437954 (and compared to which my current ramblings are distressingly redundant)
_________________
* The "AF" model designation designates its non-hifi level of performance, in fact! The hifi amps have designations starting with "HF".
** The tone controls and (if memory serves -- sorry, I am too lazy to check
) RIAA networks are the infamous Centralab "PEC" modules. Generally, these are OK and fit for purpose, but replicating their innards with discrete components is, as mathematicians are wont to observe,
straightforward.
*** I am, as I have noted many times, nothing if not
danged lazy.
