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Eico AF-4 stereo SET EL84 amp

The volume at the multiplex dosen't change because the multiplex adapter needs a fixed level input to pick up the 19khz signal(like tape out).I had the same tuner and amp,The AF4's power jack scared me that someone would plug a speaker in it!I am not aware of any accessory that would plug into it.I circled it in red magic marker to remind myself.
 
The AF4's power jack scared me that someone would plug a speaker in it

That freaked me out too when I saw that. I covered mine in blue tape

Still, nothing out the audio mono output
 
Thanks for the manual Scott. I will check it out, open a thread and see if I cant get the audio out working. I can always take it in for an alignment

edit: The 6C4 was bad and would not heat. I got a new one and changed several resistors. Works now
 
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If your reception is good, and the multiplexer decodes stereo properly,the alignment should be good.if you cannot decode stereo,the alignment,or multiplexer could be the problem.
 
Back to the amp

Since I had a problem with the volume pot not tracking well at low volume on the amp, I decided to swap the tone 1M pot with the volume 1M pot and that really made a difference.

Now the tone will normally stay right in the sweet spot of the bad vol pot and the vol pot now tracks much better and quite acceptable

The amp is like perfect now.

I think I'll do the tuner/amp case swap to put the best case on the amp.
 
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Super Nice rebuild! I bet those cases are the same as the HF-12's. I like the vintage look and they sound really nice.
 
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DSC02254.jpg DSC02255.jpg DSC02256.jpg DSC02257.jpg I finally got around to painting the Eico amp case

I took the metal case off and stripped the old paint off and painted the amp case and both screens so that they would match

I also polished the faceplate and then sprayed it with clear coat

Turned out pretty nice

These are really done now
 
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Did anyone ever find a real correct Eico schematic for these that they could post. I'd like to study the circuit a little more. Thanks, jay
 
Is the schematic in the manual incorrect in some fundamental way, Jay?
I have a copy of the manual (pretty sure it's in the public domain).
 
mhardy6647 said:
Is the schematic in the manual incorrect in some fundamental way, Jay?
I have a copy of the manual (pretty sure it's in the public domain).
Click to expand...

No, the manual schematic is the one I'm wanting. I'd like to have a copy of the whole manual. There's a nice readable schematic floating around that's not Eico and I think it has a mistake or two.

Anyone ever mod one of these? I don't want to butcher the clean one that's going in the Eico collection, but I'm having a hard time getting past "cut only" tone controls.:thumbsdn: Also, I wonder why Eico designated it AF instead of HF? I think they sound awfully HiFi to me. Maybe it was power output, or how distortion numbers rose with power output? IIRC up around real world listening hertz the distortion was `~1% or less. Maybe I'm wrong that HF stood for HiFi?



Oops, over-post, but that is exactly what I needed, you're my hero once again Mark.
 
It's on the EICO group... gimme a minute... (rustle, rustle)

EICO considered it (and I am not making this up!) almost hifi.

The cut-only tone control was a deliberate decision on EICO's part -- they figured that a 4 wpc amp didn't really have the wherewithal for boost and cut type controls, so they went with quick 'n' dirty (and cheap) cut-only tone. These were really cheap components of their day (or any other day... except nowadays, when they fetch astonishing sums).
 
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I should clean mine up someday -- not to mention give it a refreshing...
I know I've mentioned this before (probably in this very thread!); the one I have has been in my family since new. My late father got it in a grab bag (!) from his parts distributor back in the '60s and gave it, and an HFT-90, to his sister (she, also, now deceased) in Greensboro, NC. Some years back, she kindly gave it back to me.

DSC_9823 by mhardy6647, on Flickr

(there they sit, along with an HF-85 from eBAY -- first thing I ever bought on eBAY, in fact)

I am an EICO nutcase, having been bathed in EICO-produced sound essentially from in utero on through adolescence.
 
That's a great looking amp, there's something about those Eico's that sound great.
I don't have tour model but the HF-81 and the all really good sounding amps enjoy
yours

Tube
 
I have the manual on PDF. Shoot me a PM and I'll sent it as an attachement

My EICO AF-4 has been pretty quiet lately

The big mystery is why do they ooze from the control plastics? The knobs always seem oxidized
 
I'm an Eico nut too. Started with Fisher, switched to Sherwood, and ended up with Eico, go figure. :dunno: What's the deal with the B+ plug on back that looks exactly like a speaker plug? I wonder how many speakers got electrocuted by these?


Has anyone around here ever hot rodded one of these? I would want it to look stock, I'm just talking circuit improvements that can't be easily seen.:music:
 
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