Eico HF-81 again: Holy Cow!!!!

Vintage Asylum

Classic gear from yesteryear; vintage audio standing the test of time.

Thanks to all who replied to my questions about restoring my Eico HF-81 below.
I replaced all filter caps with standard grade Mallory TC series caps. I replaced the .1 coupling caps (only four of them) with Angela (Jensen) paper/oil caps. Almost all of the original resistors read within 10% or better, so the only ones I changed were the 2W power supply resistors. Cathode bypass electrolytics were replaced with what I had at hand (Spragues for the 25mFds, Nichikon for the 10mFds, Mallories for the 47mFds). Cleaned up the pots and sockets and fired her up.
My jaw hit the floor. What an unbelievably great sounding amp this ugly little piece is. I'm running it into a pair of Spendor BC-1s.
I also own and like a Scott 222 and 299, as well as a Fisher X-100, all of which have a similar tube compliment. They can't touch the Eico with a ten foot pole! Then I compared it to what I thought would be the next step up in quality, a Dynaco PAS3/ST70 combo with Triode board. The Eico slaughtered it so bad, it was sad.
What in the world makes this thing sound so good? The output transformers are tiny compared to other EL84 amps, yet the Eico has more defined bottom end than the others combined. Huh?
Maybe my ear isn't refined enough to recognize "true" high end sound, maybe you veterans here will tell me the Eico is "euphonic", "colors the sound", whatever. For sheer listening pleasure, I haven't heard better, period.
A couple of problems:
the chasis was covered in wax that had obviously run out of the power transformer. Is that common? The transformer works, the voltages are spot on, but it gets very hot to the touch. If that's its normal operating temperature, I'm not surprised the wax ran out. There is no hum through the speakers, but when you touch the transformer, you can feel it vibrate noticeably.
The controls feel very flimsy and inaccurate. I hate the fact that the Treble control for one channel functions as the On/Off switch. The rotary switches are very oxidized an worn out feeling (this unit has seen lots of use)
Im thinking of diconnecting everything including the tone controls. I'm only listening to phono, and occasionally CD, so I envision a stripped down Hot Rod version with a real On/Off switch and a quality volume control, and a quality Phono/CD selector switch, nothin else.
Have any of you guys ever tried this? What will it do to the sound?
I imagine disconnection the tone stacks would raise the gain significantly. How would I compensate for this, if necessary?
I want to add that if this were a really nice, original unit I wouldn't do a thing to change it. This is a classic, for sure. Mine, however, is worn out and rusty. But what a sound.
Sorry about the long post. Can you tell I'm excited about this thing?
epador

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Topic - Eico HF-81 again: Holy Cow!!!! - epador 10:23:38 03/31/02 (6)

Re: Eico HF-81 again: Holy Cow!!!! - hurdy_gurdyman 06:46:26 04/3/02 (0)

OK, OK, but... - JohnR 02:55:15 04/2/02 (0)

Re: Eico HF-81 again: Holy Cow!!!! - REL4 17:55:08 03/31/02 (0)

Re: Eico HF-81 again: Holy Cow!!!! - tbabb 13:29:43 03/31/02 (2)

Re: Eico HF-81 again: Holy Cow!!!! - harryz 20:39:39 04/1/02 (0)

Re: Eico HF-81 again: Holy Cow!!!! - epador 16:39:25 03/31/02 (0)

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