Recapping a pair of EICO HF-22
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Last week I put them on the bench. I bought them around a year ago.
One with the tubes, one without.
To keep the look I need to find the electrolytics, 1" 2x20uF 450V twistlocks. I'd prefer 500V ones.
The existing caps today are all 1-3/4" which won't fit in the existing pattern.
One option is to go to Hayseed Hamfest I was pounted to at Audiokarma. They make custom sizes.
Another is to leave the caps in place and use new ones underneath.
Yet another is to restuff the the cans.
And the last one is to reform the caps. I could go for it, especially when I yanked one and saw the two halves being 24uF and 26uF which is quite good: if successfully reformed, it could work just fine.
But then the cap from the other amp measured at 80uF with each half being 40uF. Which, with somewhat mangled base tells me that 1) the cap had been restuffed in the past, 2) it exceeds the 5U4 tube rating for capacitance though probably would work fine.
The two other caps (same type and value) seem factory soldered so probably original.
Decisions, decisions.
One has black tubular caps, the other has two replaced with orange drops.
Death caps are just that, death caps, need to be changed for Y-rated.
From the sch one could see that the centertap of the output stage is fed with the voltage filtered by the caps right off of the rectifier. No chokes or resistors. Despite that, the amp is very quiet and sounds great, which I had a chance to confirm today at a co-worker's place, same guy on whose behalf I p!aced the ad in "For Sale." He's just retired, as of yesterday, and I came to visit him today, and he had them all warmed up for me. He runs them with G-807 in the pushpulls, instead of 6L6.
His place reminds me of Terry's only the basement is not as ... busy
Well....I hope the iron is good, I'd sure love to eschew the pleasure of rewinding them transformers, or paying someone to do it for me.
https://www.google.com/url?sa=t&source=w...hIyiCzomc7
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Mike;
I don't know much about the EICO HF-22s but I had a friend whom owned a pair of HF-20s, he used them to power a pair of higher end Technics speakers and they sounded very nice.
They did have one drawback however, the power transformers got rather warm after about 20 minutes of use, I don't know if this was because they used a barely adequate transformer just to keep the retail price down or if it was due to some leakage in the filter or bypass caps, whilst they worked they were unrestored. I believe that restuffing might be your best option with the filter cans, some radial lead Nichicons or other Jap brand caps should fit nicely inside even if you have to stack them vertically. If you don't care then go the under chassis terminal strip route or just cut the cans open and slap them back together with aluminum tape, but I think a clean cut with an internal piece to couple the sections together looks good, and is not too obvious. From what I can recall of the HF-20 it used an ultra linear sort of setup where the output transformer had a pair of extra windings to employ some inverse feedback to the input of the preamp tube/s, that may help explain the lack of hum with the pi filter setup, of course they were also using fairly big value filter caps.
Regards
Arran
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Arran,
Yes all HFs are ultralinears. 22 and 35 models are the same, using the same transformers with 22 using 6L6 and 35 using EL34 tubes.
HF-22 is widely considered an EICO marvel as somehow this amp sounds super nice despite being very simplistic; many think that the output transformer is the reason.
Some folks mod these itroducing a choke in the filter.
I intend to leave the amp original.
I was surprised to find out the amp uses less current out of the 5U4 than the 690 radio, so the ripple rating of the Panasonic caps I use for my radios is well in excess of the required one.
The stock caps to my taste are underrated in the WV departmet, being 450V for the 435V B+ shown in the sch. I use 500V 22uF 450mA caps, so two in parallel to make the required 40uF will provide ample 900mA for the 200mA estimated ripple.
I feel lazy doing restuff but maybe I will.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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I would encourage you to find some old 1 inch twist-lock electrolytics with two positive terminals, and restuff them yourself. After you've done a few, it becomes easier.
I used Hayseed Hamfest caps in my Fisher TA-600, but every one of my Fisher tube tuners have electrolytic cans which I restuffed myself. I've done it often enough now that I am considering restuffing my own for my 500-S, 500-B and 400 receivers rather than investing in the Hayseeds.
And nothing against Hayseed Hamfest; they are of excellent quality. I may very well go ahead and use them in my 500-S because it is quite possibly the Fisher receiver with the shortest production time and is likely second only to the 1800 receiver as for rarity and I feel that it, like my TA-600, deserves the best.
--
Ron Ramirez
Ferdinand IN
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Ron
The caps I have seem original so I have extracted them and will be cutting them open tomorrow (I have a bandsaw at work that I use to cut my lytics).
Mike
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Parts from Mouser came Friday.
Capacitors and tips for my soldering iron.
Have finished recapping yesterday.
I went ahead with restuffing the twistlocks. The high ripple Panasonic 22uF caps went inside. One of the twist tabs on each cap got soldered to the chassis. Now that I have chisel tip it got easier.
I used Sprague Atom TVA series for low-voltage axial feedback electrolytic caps.
I used Vishay Röderstein film caps for the film caps that needed to be replaced. Which is all except 0.1uF interstage DC blockers, which I fond were just fine.
I also replaced the 0.033uF Death Capswith X2/Y2 safety type.
Had to replace 220K resistors, were way out of spec, the rest seems very good.
Now to the tubes.
I will need full set of tubes for one amp and some for the other. However since tubes, at least the output, need to be somewhat mached, I think I'll go with full two sets. (One set had no tubes).
I had 5881 in one of them, but one is bad.
Also need the shields for EF86, both are missing.
And the last one: where could I get the RCA jacks, the panel mount type with two-screw mount? Mine are oxidized, I'd like to replace them.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Yesterday I received the tubes from Jim McShane.
I thought of buying vintage US tubes but he advocated Tung Sol new Issue (Russian made) , and since his prices for matched 6L6GC are even better than in Tube Depot, I ordered two full sets of tubes (I had partial set for one as one of the two 5881 was bad, plus both EF84 missing), I thought I should make the two as uniform as possible.
Today powered them up with a small 5W 8ohm speaker for a load, used my ipod as the source. They both work fine.
One needs the plug with shorts, I ordered one.
Both could use newer RCA jacks but this type is not to be found anywhere, so at this point it is Deoxit.
Tomorrow will try to put them to my Cornwall Klipsches.
Its getting close to setting up a full stereo in the billiard place.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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The AudioKarma guys speak very highly of the Russian Tung-Sol reissues. I have not yet tried them but I'm thinking of putting a set of T-S 7591s into my Fisher 500-B when I get around to restoring it.
I do not know offhand where you might find the RCA jacks you seek.
--
Ron Ramirez
Ferdinand IN
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I highly recommend Jim if you need these or anything else for HiFi. Very easy to deal with, to xtremely responsive - emails answered within less than 5 minutes, very reasonable prices, and what he says he does.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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I found (serendipitously) a source of the NOS RCA jacks that are used on my Eicos, and might be used on some other equipment from 60-s.
I tried it before to no avail.
Here they are:
https://www.ebay.com/itm/10pcs-RARE-MARA...1438.l2649
The guy also sells them by a couple.
I bought a bunch (negotiated a price down a bit).
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 04-10-2018, 07:40 AM by morzh.)
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I remember those.
The seller's prices are ridiculously high, but if one cannot find these anywhere else, then the seller has the buyers over a barrel and he knows it.
--
Ron Ramirez
Ferdinand IN
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I nocked it down to $2/piece and free shipping, and bought 20 pieces.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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I have a number of used ones kicking around that I extracted out of junk chassis, and out of various radios where someone decided to add a phono jack to equipment that was never intended to have them, such as any radio built prior to 1938. RCA jacks are still in production, but I don't know whether the old style ones with a phenolic insulator are, there are some really inexpensive ones available but the mounting is different, they are the kind that are secured by drilling a 3/8'' hold in the chassis, and are fitted with a large nut and washer like a potentiometer.
Regards
Arran
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Arran
That is exactly the problem: I looked through catalogs, Mouser etc, this type is no longer being made.
eBay also turned nothing. Until I found this looking for something entirely different.
I had to sandpaper my Eicos' jacks, inside and out - they were badly oxidized and were making scratchy sounds when plugged into. So I think this is a good thing I found these.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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Well, here's the stereo.
Obviously it is no lobger just about the HF-22s, as I had to add aa source and a preamp. So I did. Will try to test tomorrow; I know the CD works (bought a used Marantz, same as the one I bought new, only it is 1K less). I hope the Mac (yes it is a C22) works, at least it was promised.
There. I hope I won't go for the 3rd one, it ain't cheap.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 04-29-2018, 06:43 PM by morzh.)
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