Is the Eico HF 81 really that good?

Amhifi, I think its pretty darn cool that your Eico is associated one way or another with Neil Young. You truly do have a very special piece of gear.

I'm not sure if it's bad etiquette to comment on a thread that has been sleeping for over 5 years but having recently acquired an HF-81 which I am currently restoring I thought I should share some of my experiences. A little background: I have been in the industry for several decades, have worked on and restored many amps and have designed components while working for Mark Levinson (the man), Speakerlab, Antique Sound and others. I believe I have a knack for getting real musicality out of a circuit design and likewise I try to do the same when I restore old gear. The Eico came to me in nearly original condition and quite well preserved. I replaced the electrolytics first and foremost using Elna Cerafine and a JJ multisection cap for which I had to modify the opening on the chassis. I also replaced all tubes with new production JJ and Mullard. I used Cornell Dubilier as DC coupling caps to the output pentodes and Mundorf Supreme in the first two stages. Next phase will be to carefully replace some of the Allen Bradly resistors that have drifted a bit beyond acceptable limits but boy does this thing sound good. As mentioned before the magic is in the output transformers and of course the circuit which is interesting to say the least. I have left the tone circuit intact but bypassed the balance or "focus". Here's an interesting fact I don't hear much about- these OT's are wound for 16 and 32 ohm outputs. In my mind this may be part of what makes the magic as the secondary impedance is rather high- much higher than in other output transformers. The price of these units has gone through the roof but I have to say so far it's worth it. For a tweaker like me it's a great project. Nice to read some insights here.

Nice write-up, Pokee. Not quite an 81 but I have 2 pairs of HF35s. 35watt mono amps. One is a Stu Remmington rebuild with chokes and fixed bias. They are glorious.

The sole reason why I am a long time Agon member, musicophile and gear nerd is because, beginning early in 1967, I moved to Brookline, MA, and my new and best friend's dad had an Eico HF81 fed with a Dual table powering AR 2s. Over the next couple of years I heard on that system, in a large living room, for the first time, just-released Hendrix, Beatles, Tull, Airplane, Stones, Janis, Who, Zep, Taylor and others. That system filled and energized that room and I will never forget it.

If the Eico HF81 had anything to do with, yeah, it's a good one.

Nice job pokee great read