Need some advice on what to do with a pristine eico hf81

[Majkl]

Let me start by declaring my ignorance and I think luck. I heard about the eico HF81 but I didn't know very much about it and have never had any tube amps or equipment of this age before. I ran across a gentlemen who had one and said it was in pristine condition.

I'm thinking how pristine condition can this thing be in? I mean its from 1958 or so. Anyhow I went out on a limb and picked it up from him for $400 which I thought was a little high but not out of the ballpark.

His uncle had passed away 2 years ago and had been an electrical engineer by trade and was the original owner of this eico. He had stoped using it in the early 1970s and it sat there unused on a bookshelf until now.

Talk about a time capsule. I have been reading on these forums about the restoration work that is done to these amps and they are talking about replacing this and that and the various non original parts in their amps that they are swapping out because they feel that x y or z is a better match or provides better performance and so on.

So here is my question. What if the eico was 100% stock and original and outside of dust needed nothing. Was assembled by an electrical engineer and all the soldering is done right and precise and everything is clean with no visible rust or degradation at all. Maybe a couple of contacts have a tiny bit of corrosion. If you were not intending on keeping it would you clean out the dust and call it a day. Would you leave the dust as it is and how they do with "barn finds" and cars and pass them along in their original condition as found in the barn dust and all. Restore and replace parts or leave in all the original parts.

I don't know what applies in this case since a lot of the restorations I seemed to see started with an amp that needed polishing and repainting and had some parts that were non original already and so on. I am inclined to think that one that basically looks like it just rolled off of the production line and well assembled by a professional shouldn't be messed with.

Any advice or help would be appreciated. I want to pass this on to someone who loves this kind of amp and when I do that I want to make sure I did the right thing with it and did not detract from it in any way. Its quite spectacular like a little time capsule. Hardly a scratch on it all the colors are vibrant the front shinny and beautiful. I have attached pictures so someone more knowlegable than I can make a better assessment.

Thanks for your help.

Mike

 

[silversport]

I would not leave the dust on and in it...I would want all of the tube sockets cleaned and the unit DeOxit'ed...better still...I would want someone who knows what they are doing to go over it before ever plugging it in and trying it out...

My 1959 HF-81 was built by an engineer and in very nice condition...when I bought it, it was still being used by the previous owner and but for some new Tubes, it was fine for about a year when it showed that it needed some attention...

I sent mine to Craig at www.NOSValves.com (and I HIGHLY recommend him and he is on this Forum) to be gone over...it has been running fine in my rotation (but for some cleaning and DeOxit) since 2006 or thereabouts...

mine sounds wonderful and pairs very well with all sorts of Heritage Klipsch speakers...

Good luck with yours...

Bill

 

[Majkl]

Bill,

Thanks for the advise. I went ahead and cleaned it all up and went ahead a fired it up. After a little digging through the documentation to figure out how to hook everything up since nothing on the back is labeled I was able to give it a listen.

It works perfectly outside of some scratching sounds when you rotate the volume dial. Probably needs some contact cleaner but otherwise awesome. I see the fascination with the tube sound now it is really nice. I had it hooked up to a set of Wharfdale Modus 1.6 I had sitting around in my office and it drove them without issue and at respectable volume levels. I wasn't expecting much for the little bit of wattage the amp puts out but it caught me off guard with how well it drove these speakers which are not small.

Now all that's left if for me to find a new home for this beauty. With one this clean and original I don't imagine that will be too difficult.

Thanks again for your reply and advice.

I just picked up a pair of Eminent Technology LFT8 speakers so I am going to go play with those now....

Mike

 

[FB night]

Hi, I have worked on a few of these, they are great sounding amps. If your intention is to resell, just blow the dust off and take very good pictures. In my opinion, only restore it or have it restored if you are planning on keeping it. If restored to sell, new parts put in the amp, as well as the work done to restore it, will fall under hard scrutiny by others as they ponder how much the sound may have changed from the original, or if the person who restored it actually knew anything about restoration. Changing resistor and capacitor types in the amp will change the sound, and best left to the next owner. The best way to start one of these vintage amps is with a variac variable voltage device, slowly, and not exceed the specified voltage rating of 115 - 117 volts, whatever is designated on the back plate. Something like this, will sell for more if you can confirm that it is putting out sound from both channels, and so the transformers could be called good, but know that there is a risk involved also in doing this. Most of what I keep, I dont even put power to, until it is at least partially restored. But if I did, I would have slowly brought it up to about 100 volts, listened for sound,watched for any signs of trouble, and backed out of it and shut it off. It needs serviced. What you paid is not too much for that condition, IMHO.

 

[Mossback]

I own 2 Eico HF 81's and have rebuilt several others for friends successfully. They can be rebuilt with modern parts into a wonderful sounding little guy. I love them.
FB night is correct do as he suggests. One thing don't use it. The electrolytic caps in it are well beyond their shelf life using it would be pushing your luck.

 

[Shadowdog]

Really nice amp!

I second not using it until you replace the PS & Bias supply caps as you can ruin a transformer when those ticking time bombs let go as they have a limited life span. The PS transformer runs pretty hot as it is and caps going bad will easily kill it,

The coupling caps should be replaced on a tube amp , but that one uses disk caps that do last, but may not be sonically the best. There is a lot of debate on replacing them if you research that!

You could repair it easily yourself so it's reliable and just enjoy it! Just take many detailed pictures & replace one cap at a time & then test it! I found tubes less fatiguing and have similar HF-12's. I also like tube amps for the fact that they are repairable & it can be easily done on many!