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My HF-81 the good and the bad


NOSValves

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I came home from work early today to find my HF-81 was waiting at my Door Cool.gif .

Well I wanted a project and it looks like I have one. The wiring inside is a mess !! In fact I'm scared to even turn it on LOL !!

Tested all the tubes. All the 6BQ5's but one are shot. No big deal. They weren't Original they were Tong Sols.

The 12AX7's all test great and for some crazy reason there are 5 !! all EICO Mullards.

The 12AU7 there was only one was a Tung Sol and it tested good.

The EZ81's Tested great and they are EICO Mullards.

So my luck didn't hold out !! I have a basket case on my hands. But I'm not complaining at all. The tubes alone are worth more than I paid. Besides I wanted something to work on anyways Smile.gif .

This project I think is going to be a complete rebuild/restore the wiring, the case, it all needs attention. So this is going to be put off for a while till I go thru all my other stuff and get it all up to snuff and learn a little more about what I'm doing.

HF81_1.JPG

HF81_2.JPG

HF81_3.JPG

HF81_4.JPG

HF81_5.JPG

Well there's the story. I'm not regretting this purchase at all. Just thought I'd show you all my project before I start fixing it. Of coarse Mobile and MDeneen will be called on many times to help me when I get started on it.

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First of all, I have seen FAR FAR worse EICOs than that! Remember, some loon at home likely wired this 35-40 years ago and to be honest, that unit looks DAMN clean inside despite the apparent helter-skelter wire scramble. Really, it is a very clean example for what you paid. Dont be put off by the squirrel nest wire brigade. Yes, it could have been done better but as I said, I've seen worse.

The transformers look in good shape with no wax coming out on bottom. I would say you got a great deal.

As for testing the 12AX7/12AU7, remember it is hard to get accurate readings on these minipin tubes sometimes. Sometimes they will read lower than than measure, even on good testers.

Make sure you get a matching 12AU7. By the way, it did have the tube covers right?

I would say you got a good deal there - dont be so down about it.

kh

This message has been edited by mobile homeless on 03-06-2002 at 02:36 PM

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Mobile

Rest assured I don't feel bad about the deal at allSmile.gif. I expected it to be a mess at the price I paid. Oh and yes I received the 4 tube shields. The unit is complete. The guy says it works but I'm not going to fire it up with that wiring the way it is and right now I have too many projects to finish. With my Scott 222C mods and 299 restore and my LT-110b Tuner to restore. I'm swamped with my new hobby. I don't want to dive into the HF-81 when I'm in the middle of the others. I will give it my all when the others are done.

What I'm wondering is how it ended up with 5 EICO/Mullard 12AX7 tubes. I test my tubes on my like brand new put in a time capsule EICO 667 tester. For leaks, shorts and balance. Here's how they scored.

HF81_6.JPG

HF81_7.JPG

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Fire the damn thing up!!! How can you not be curious?

See below:

eico_inside_large.jpg

This is the wiring on the BETTER sounding EICO! YEs, I have done some thing with it since then, but this is the way it was when I bought it and it sounded DAMN good. See that review I wrote? That was with THIS wiring without a single exception. Yes, yours is a bit more at odds, but for the love of Pete, fire the beast up! Live a little! Of course, a Variac is a nice thing to have...but what the hell!

kh

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Mobile

There is no way I'm firing this thing up it doesn't even have the fuse socket wired in no protection what so ever. If something shorted bam! I could lose the tranny who knows what. I'm going to fix the wiring before I chance that. I believe someone modded the wiring bigtime anyways. Most of the soldering looks as good as the factory did on my Scotties but other parts look like a child did it. I'm waiting I just can't chance it burning something up or worse knocking me on my A$$ with a jolt.

Craig

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looks clean to me.

the power supply caps don't even look squishy.

Nice clean trannys, not burnt looking.

Would a guy just go by section by section, to straighten out the wiring mess?

Gee NOS, your picking up on this hobby quick!

I think you scored!

Now I really have to research Eico gear, Trust me.

Good Luck!

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Mike

Honestly I do this with hobbies all the time I drive my wife nuts she can't figure out what I'll get into next. I usually get involved with something like a madman until I've mastered the art and then I just stay in the hobby casually. I just have a lust to learn !!!!!

Craig

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I'm sure some clairvoyant armchair expert looking at the pretty color photos can tell you if trannies are good or not

I just was complimenting the guy, because the underside of the unit doesn't look dirty or burnt, from his 'pretty pictures'.

WTFDIK!! Sheesh!

I just hope this wasn't a insult, and directed at me.

THANX!

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mdeneen,

Good post. I found it inspiring. It makes so much sense to not even mess with that existing wiring when all you need is a schematic and the original instructions, which I am sure are easily obtained. With the thing stripped back down, you can really clean it up and then, like you say, carefully replace the parts and then do a thorough and tight solder job that you can be confident about. Maybe if it was definitely known to have been a reliable unit just prior to purchase or a time-capsuled factory wired unit, then I could see carefully powering it up. Think how dumb you would feel if you powered the thing up, it goes Kabloohey, makes smoke, fire, and funky smells, and then you have to think about rebuilding what you may have rendered even closer to worthless. Caution here seems a better way to protect the investment, however much a bargain it was.

Just my two senators worth. I too may be going down a similar educational path with this hobby, it is good to have your experience so generously shared around here.

-smoked and mirrored

-

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What would we do without mdeneen? Christ, I know I'd be lost.

Enjoy the ride and experience. You will be the first of my knowledge to do this with the EICO HF-81, at least to that extent. Power to you. Most poor souls suffer with the original amp with some parts replaced. A damn more than a few are foolishly happy, risking life, limb, family, and surely getting imperfect sound. Damn foolish people on the East Coast.

kh

This message has been edited by mobile homeless on 03-06-2002 at 10:48 PM

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Kelly,

With this unit now considered to be such a sought after gem ( almost a holy grail, thank you) and prices on eBay at the moment going to the $300+ range for a halfway good one, it seems like a little caution is in order, especially considering that the fusing was tampered with, and some of that soldering under there looks a bit imprecise and messy. I remember back in ham radio days, some guys would build a trasmitter from a kit, and it would not work properly right from the start because they were careless. Then they sometimes had a big frustrating job trying to locate their "mistakes". When all else failed, they would bring it to a professional shop and thus loose some of the budget edge they had going by doing a DIY kit in the first place. I think there is a happy medium between you and mdeneen.

<...and her name is Madame Lyssa....she has a neon sign you can see from the highway>

no, I remember you have at least one LP with Jerry Mulligan.......

hey, some of that Shorty Rogers stuff on Atlantic was pretty cool.

-bebopped and rebopped

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I've been so busy messing with my 222C I missed all this fun.....Darn.

Really guys I bought this unit with the thought that I would just use it as a learning tool. You can't buy kits like these anymore and I'll end up with much better parts than most if not any HF81 has out there but this will take time. I'm not even going to start it for some time.

First I'm going to finish my Scott 222C. It is going to get all kinds of mods before MDeneen and I are done. I want to make sure that it has a chance against a full mod HF-81. The 81 will never have the looks of the Scott that's for sure it just doesn't have the cool quality Scott look even with the greatest paint job. The knobs and face plate on my Scott just look 60s quality at its best.

I haven't even done a serious mod to the Scott yet and it sounds real good to my ears. So I think the 81 has a big hill to climb before it can take the main spot in my music listening.

Craig

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I'd jump on it, but I just worked out a deal with Jazman for his Eico HF-12 Mono Amps.

I have seen wiring of the inside of Leaks before, Mike.

Wiring in right angles, caps lined up in a row on Phenolic Boards with solder lugs.

Serious attention to detail.

Why don't they do this anymore?

Is it some lost art? I guess so.

I haven't seen wiring on Quads.

Would the A.G. Tannenbaum ***/OP Manual for the HF-12 be worth using?

Or should I find better?

Would there be wiring directions, to wire these units in the proper manner?

Yup, It's my first, but I am in no rush, whatsoever.

And your point is taken on looking at pics, you can't tell what's up with a Component until it's in your face.

You do come up with the clean Dynaco links, though.

And cut Holsten a little slack, he's a good guy!

He's on our side.(It's your choice, however.)

Thanx!

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