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Eico HF-22's total reassembly.

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

  1. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Thanks guys...my ignorance is showing.
    Yes, the resistors indicated are all listed as 1 watt, which is what I installed. I will order 2 watters if that is best. R10 on the Eico parts list gives a value of 28.75K. Either value OK?

    Replacing these resistor are for long term and shouldn't keep me from proceeding with testing and actual use here at the beginning...correct?

    martin
     

     

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  2. edlipman

    edlipman Active Member

    Messages:
    216
    Location:
    Mt Pleasant SC
    Your wiring looks good with the use of spaghetti tubing on most of the component leads , but not on the leads for the CL 90 and the orange drop death cap.
    As seen the orange drop lead goes under the power cord at the fuse
    holder , if this gets pressed down a bit the lead will touch the chassis. The CL leads also need spaghetti tubing as it looks like a potential shorted AC line if the two leads touch.
    There is also a naked lead that appears to go over one of the power transformer bolts , this lead should have tubing too.
    Hope this helps
    Ed
     
  3. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    9,678
    Location:
    Ball Ground, GA
    Martin -- The 1 watt units will certainly work, but will be stressed over time as mentioned. Replace with 2 watt units at your leisure for worry free long term performance.

    The original value specified for R10 in the earliest kits was 27K. However, from a theoretical standpoint, the value for R10 required for best AC balance from the phase inverter stage is 28.75K. As Eico's audio kits grew in production, they were able to have exact value resistors produced, and so updated later kits with the more exact value. As an alternative, you could use a 33K 2 watt resistor with a 220K .5 watt resistor in parallel with it for R10. This combination will produce a value of 28.70K, which is within .25% of the target value of 28.75K.

    Dave
     
  4. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Ed,
    You're right, those areas do need to be addressed. I've had to rearrange that area a couple of times and hadn't settled on the final resting spots till just yesterday. I'm still trying to devise some sort of support for those "loose"terminations. In the photo's the leads look closer than they really are.

    Dave,
    I'll order some two watt replacements. Glad to know they won't hold up progress till I get a final parts order together.

    martin
     
  5. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Dave,
    Could you show me the math on how you achieved the 28.7K by running those 2 resistors in parallel?
    For the 18K, I have a choice of 15K or 20K.

    martin
     
  6. MX117.MC7150

    MX117.MC7150 Listener Subscriber

    Messages:
    5,261
    Location:
    Jersey Shore
    Beautiful work. Hope my project turns out as nice.
     

     

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  7. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    9,678
    Location:
    Ball Ground, GA
    Martin -- the well established formula for determining the value of two resistors in parallel (dissimilar or otherwise) is: R(total)= (R1 X R2) / (R1 + R2)

    where R(total) is the result of the paralleled resistors, and R1 and R2 are the individual resistors.

    Therefore, applying the formula to the question at hand:

    (33K x 220K) / (33K + 220K) = 28.6957K which I rounded to 28.70K in my response.

    For ease of calculation, simply omit the thousands (K), and add it back in in the final answer since that is the level the resistors represent. Therefore:

    (33 x 220) / (33 + 220) = 28.6957 Since the resistors are all in thousands, so is the final answer as well.

    Hope that helps!

    Dave
     
  8. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Well boys,
    We're grooving in mono and all looks good.:music:

    Sony Discman summed to mono going in and a single KLH Model 17 on the back side. Hey...they were handy. :D

    Been playing about 30 min now.

    The 6L6's have that nice little cherry on top. :thmbsp:

    Power transformer is only a tad above room temp and OPT is cool to the touch.

    The low end seams to be getting better by the minute as the caps start their burn in. :thmbsp:

    Mid's and high end are smooth and easy on the ears. :thmbsp:

    It all sounds very clean and clear...not a lick of hum! :thmbsp:

    We can get into the fine tuning later.

    Very, very, very cool!

    Martin
     
  9. Dandy

    Dandy Super Member

    Messages:
    4,494
    Location:
    North West, UK
    Congratulations! This Mullard 5-20 design is a great sounding design--and yours looks cool too.

    Take your time with the second one.
     
    Last edited: Dec 30, 2011
  10. MX117.MC7150

    MX117.MC7150 Listener Subscriber

    Messages:
    5,261
    Location:
    Jersey Shore
    How about a pic of the 'finished' amp. More eye-candy. :thmbsp:
     
  11. audiodon

    audiodon Addicted Member

    Messages:
    9,294
    Location:
    Arlington, MA
    Martin,
    Glad you're hearing it. That's good news.
     

     

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  12. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Dandy,
    I'm trying to heed your sage advise and take my time, but I'm feeling excited and anxious for "stereo".
    The first amp was like taking a vacation. Taking in the scenery and the joy of reaching your destination safely. The second amp feels like the return home. All the while telling everyone, "stopping?...we're not stopping, we're driving straight thru...you'll just have to hold it!" :D
    I'll try not to fall asleep at the wheel.

    Glenn...you'll just have to wait till we're seeing in "stereo" as well. :thmbsp:

    Don...thanks for the nod.:thmbsp:
    I really like the documenting you're doing over in the fisher forum. The work you're doing on the SDS boards and the cleaning / care of the Fisher's is needed.

    I picked up a couple of toggle switches that I'm considering using on the Eico's...seeing that the holes are already there. I like them because they are nickel plated, short stemmed and unobtrusive. However they make a horrible hollow clank when moving the stem from one position to the other. Clank...clank...clank! :thumbsdn: Like the sound a door closing on a cheaply made car...hollow and sad. :nono:
    So either I find a way to deaden the sound or just plug the holes with some electrical service caps and switch the units on and off with a quality power strip.
    Any suggestions?

    thanks
    martin
     
  13. MX117.MC7150

    MX117.MC7150 Listener Subscriber

    Messages:
    5,261
    Location:
    Jersey Shore
    If the switches have the threads available (most do) you could try a rubber or plastic washer on both sides of the sheet-metal when installing. May dampen the noise. Or, try a different switch. At $2, each, you could try several.
     
  14. marloubow

    marloubow Best Day Ever

    Messages:
    767
    Location:
    Enid, Oklahoma
    Gentlemen...1+1 = stereo!
    I just finished the second amp earlier this evening and even though it's only paired up with a sony discman and a pair of homebrew speakers, I must say, these Eico's sound very nice.

    Before I forget, want to thank Reece over at videokarma for shooting me a couple of matching octal sockets for these units and Tom Bavis for digging me up a couple of tube shields. Don't look quite the same, do they Tom? :D

    I still have questions about the validity of these tubes...quite the mixed bag.

    Also about biasing on these amps.

    But for now, some pictures.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  15. Dandy

    Dandy Super Member

    Messages:
    4,494
    Location:
    North West, UK
    If they sound as good as they look, fantastic! I think the toggle switches would be okay, maybe dampened as suggested.

    Alternatively, you could use the holes to install a little pilot light for each one, drawing bulb power from the 6.3V filament heater wiring. I find that it is useful to 'see' if they are on or off, esp in daylight.
     
  16. bhamham

    bhamham AK Subscriber Subscriber

    Messages:
    1,994
    Location:
    Austin
    Awesome! Well done, Martin :thmbsp:
     

     

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  17. dcgillespie

    dcgillespie Fisher SA-100 Clone Subscriber

    Messages:
    9,678
    Location:
    Ball Ground, GA
    They really do set a standard for a complete rebuild! Superbly done!

    Dave
     
  18. Mid-Fi

    Mid-Fi AK Subscriber Subscriber

    Messages:
    1,149
    Location:
    Joplin
    Something is wrong here, I just read this thread and actually understood about 1/2 of it. Would have been hopeless a year ago.

    Wonderful job Martin! The assembly jig floored me not to mention how you saved the lettering. I have a EICO I want to build a chassis for and rebuild but don't have your focus. I can take take a lesson from you and finish other projects before starting another.

    Thanks to all for sharing.
     
  19. 131east23

    131east23 ...near Frank's Pizza!

    Messages:
    3,500
    Location:
    Oregon
    Those are so beautiful!
     
  20. shelby1420

    shelby1420 Enjoying the music.....

    Messages:
    4,301
    Location:
    Oromocto, NB
    Stunning Martin!!!!
     

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