Eico HF-22's total reassembly.

Discussion in 'Eico Place' started by marloubow, Nov 17, 2011.

  1. marloubow

    marloubow Best Day Ever Subscriber

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    Sold!!!...to the Gentleman from Connecticut...I'm sure you'll be very happy. :yes:
     

     

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  2. chinacave

    chinacave Its Like a Jungle Sometimes; It makes me Wonder Subscriber

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    What he said.
     
  3. skypilot_one

    skypilot_one New Member

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    Shoreline, CT
    I have a working all original pair w/ cages. I need to check the voltages to see where they stand but the amps still sound fine.
     

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    Last edited: Jan 23, 2012
  4. marloubow

    marloubow Best Day Ever Subscriber

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    Update,

    I got the 2 watt resistors installed, as well as the "death cap" and the AC rewired...thanks again Dave.

    The matched quad of Russian 6P3S-E's (the box lists them as 6n3cE's?)
    and a matched pair of EH5U4GB's came yesterday. I didn't notice a huge difference, but will hold off listening judgements till I have them in a setup more appropriate than the "testing" setup their in at present. However, to say the least...I'm very pleased!

    Amp A has only the very slightest hum. Can only hear it if I put my ear up to the grill. I thought it was one of the 5U4's...have to chase it down.
    Amp B is dead silent.


    I've got it in my head to bi-amp my AR3a's. The Fisher 800c for the low end duties and use it's center channel taps to feed the Eico's for running the upper end. I'll let you know.


    One things for sure, the new tubes sure evened out the numbers.


    Old Numbers

    Amp A. Before current limiter / 118.8. After current limiter / 116.1

    Amp B. Before current limiter / 118.8. After current limiter / 116.2

    Amp A
    V3 pin 3 / 414
    .....pin 4 / 417
    .....pin 8 / 36.2

    V4 pin 3 / 410
    .....pin 4 / 415
    .....pin 8 / 36.2

    Amp B
    V3 pin 3 / 401
    .....pin 4 / 405
    .....pin 8 / 36.3

    V4 pin 3 / 400
    .....pin 4 / 405
    .....pin 8 / 36.3

    Amp A. AC across pins 2 & 7 - 6.28V

    Amp B. AC across pins 2 & 7 - 6.28V


    New Numbers

    Amp A. Before current limiter / 119.6. After current limiter / 117.0

    Amp B. Before current limiter / 119.6. After current limiter / 117.0

    Amp A
    V3 pin 3 / 419
    .....pin 4 / 423
    .....pin 8 / 36.7

    V4 pin 3 / 418
    .....pin 4 / 423
    .....pin 8 / 36.7

    Amp B
    V3 pin 3 / 420
    .....pin 4 / 423
    .....pin 8 / 36.9

    V4 pin 3 / 419
    .....pin 4 / 423
    .....pin 8 / 37.0

    Amp A. AC across pins 2 & 7 - 6.36V

    Amp B. AC across pins 2 & 7 - 6.36V

    Thanks
    martin
     
    Last edited: Jan 22, 2012
  5. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

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    Martin -- Again the readings look great! If the hum in one unit concerns you, here are some things you can try:

    1. Remove the input cables and short the inputs to ground with a shorting plug. This will help identify if the hum being generated externally or internally. If the hum goes away, then it is originating in an external unit (i.e. preamp) -- or is the result of a ground loop that can sometimes occur when two mono units are used in stereo installations if multiple ground paths exist.

    2. Identify if the hum is 60 Hz (traditional hum as heard from an open ground for example) or 120 Hz (one octave higher) in nature. If it is 120 Hz hum, that is always power supply generated. This can be caused by poor grounds on the electrolytic filter caps, bad electrolytic caps, or (often) a mismatched pair of output tubes. Check all ground connections in the power supply, and for the latter thought, swap the output tubes between the two units to see if the hum follows the tubes. If it does, you've identified the source of the problem.

    3. If it is 60 Hz in nature, check the lead placement of the heater wiring for the EF86 input tube (pins 4&5). These leads should be tightly twisted and routed away from any of the grid terminal wiring (where the input jack connects to) to minimize any hum being induced into the signal chain at that point.

    These thoughts will help give you a start if the hum is serious enough to chase down. Otherwise, enjoy, and good luck with them. Your work is an inspiration to all of us!

    Dave
     
  6. skypilot_one

    skypilot_one New Member

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    I'll second that. From your rotisserie to paint, rebuilding and troubleshooting you do a fantastic job!
     

     

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  7. marloubow

    marloubow Best Day Ever Subscriber

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    Thanks Skypilot_one,
    I'm keeping an eye out for a tube pre that will compliment them...just maybe not so much work. Oh, what the hell...it was fun!

    Any pre's out there that need a lot of TLC?

    Dave,
    Will look into your suggestions soon. My current pre (Yamaha C-70) that I'm using with the Eico's at present has always had sporadic channel issues.
    Thanks for the nod as well.

    martin
     
  8. MX117.MC7150

    MX117.MC7150 Listener Subscriber

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    If you haven't hit the pots and switches in the C-70 with some Deoxit ProGold in the past couple of years you may find that doing so will solve your sporadic issues. If you don't wish to tackle solid-state, AK member Avionic up in Iowa or EchoWars in KC are both fairly local to you.
     
  9. skypilot_one

    skypilot_one New Member

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    Location:
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    So, how do they sound?
     
  10. marloubow

    marloubow Best Day Ever Subscriber

    Messages:
    782
    Location:
    Enid, Oklahoma
    Eico HF-22's...revisited

    Hey all!
    Sorry that I left this thread just kind of hanging.

    Skypilot_one asked..."so, how do they sound?"

    Well, at the time I was waiting on a pair of 5U4GB's to come in (hoping they would help with the hum issues that I was experiencing) before I posted any listenig impressions.
    At the same time, I discovered that my C-70 had a tone relay that went south, also a big restore (Grommes/Seeburg) job got dumped in my lap as well as a pair of Yamaha NS-690 the needed a lot of help, and retrofitting a RCA 67V1 console.

    So now that all that stuff is either restored or repaired, and the new tubes are in...on to the Eico’s.

    The first thing looked for was the hum…it was totally gone, except for the slightest hint at max volume, and that was with my ear up against the grill. Cool…very cool!

    I figured the critical link in the chain would be the speakers, seeing the Eico’s spec a power output of 22 watts / 44 peak per channel.

    Source is a Denon DVD 2200.

    Preamp is a Yamaha C-70 (did try a Kenwood Basic C2, but came back to the C-70).

    So after about 20 min to let the Eico’s warm a bit, I started in on some speaker swapping.

    First were some JBL 4410A’s and they sounded pretty good, but they sound much better with my Fisher 800c.

    Next were some home grown, home designed MTTM’s…nah, that’s not a match.

    Next were a pair of recently acquired and refoamed Infinity RS-3000’s. Now that’s more like it. The bottom end was lacking a bit, so I hooked a little homegrown 8” powered sub to the C-70, just to flesh out lows and that did the trick.

    After fiddling with the C-70’s parametric tone control for a bit (sorry guys…I’m a fusser) I started running a variety of my favorite music thru the system.

    “So, how does it sound?”

    After all the work I put into these amps, my hopes and expectations were fairly high. I’m happy to say I’m not disappointed…quite pleased as a matter of fact.

    The first thing I noticed was how wide open the sound is, really good separation, with each instrument distinct and accurate.

    The high end cymbals are clear and not in the least bit harsh. The vocals smooth, articulate and out front when their supposed be. Strings have good clean decay.

    As I mentioned before the low end lacks, but I’ll chalk that up to the speakers themselves. I’ve no doubt the Eicho’s would really shine with the right speakers. I’ll just have to keep looking for that perfect synergy. At the moment I quite content with the present setup, knowing, that they can still sound better.

    Anyone out there with recommendations on what might pair well with these Eico’s?

    Thanks for all the help along the way.

    Martin
     
  11. drtool

    drtool It might get loud In Houston Subscriber

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    Hi Martin, Top Notch Job :rockon:. I deal with paint and you really brought those Eico back to stunning condition. Great job. I have a pair of 22's my self and one is up and running . If you get a chance to pair up the Eico's with Old School Kilpsch ( I run La Scallas ). Or any good horn system I think you will have an enjoyable experience to try out.

    I also heard some Focals, with a set of fully restored HF22" and that set-up was very sweet too.
     

     

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  12. DGSTUDIO

    DGSTUDIO New Member

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    I recently acquired an HF-22 and HF-20 in not so good condition, rusty and missing tubes. Assuming the transformers are good, I'm thinking of rebuilding them into new home built chassis. Probably aluminum plates with wood sides. With the HF-20 being an intergrated amp, I could not make a matched pair of them without a rebuild. I thought I would try to get the HF-22 working, then swap in the transformers from the HF-20 before committing to building the pair. I could use some help with upgrades. I'm getting a lot from this thread so far. Any warnings about building new cases?
     
  13. drtool

    drtool It might get loud In Houston Subscriber

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    DG You should have the same OPT's on the 20 and 22. Hope so, that is how the two left the factory. (32004) stamped on top. I believe you can use the "tape in" on the 20. So in affect, you have 2 HF22's.
     
  14. DGSTUDIO

    DGSTUDIO New Member

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    Both the power and output transformers are the same. The HF-20 uses 12AX7s and 12AU7s instead of EF86 and 6SN7s. I don't know how much difference it makes, but I want them to be clones. I will rebuild the front end to be the same as the HF-22. Maybe I should make them both the same as the HF-20? Everyone has their priorities and aesthetics means as much as sound quality to me. I want them to look and sound exactly the same.

    I'm considering solid state rectifiers and I will probably see how quiet it is before I add chokes. Maybe add a pi network power supply with a resistor between caps before trying a choke. I'm not much of a design engineer. I've been an electronic hobbyist for over 40 years, mostly solid state. I've been reading up on biasing and feedback.
     

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