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The Collins 75A-4 Thread.

Discussion in 'Amplitude Modulation' started by N6YW, May 16, 2017.

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  1. N6YW

    N6YW Ham Member Volunteer Moderator QRZ Page

    Carl...
    That was a great contribution in a hands on manner, through experience tempered with enough detail to warrant
    further discussion.

    The vintage original camp scoffs so much about keeping things stock, you know the one's... the "Collins Cork Sniffers"
    and I get that, I really do. Car collectors, especially Concours types wrote the book on such things, but then you
    cant' drive a car on the original 50 year old battery, tires, belts & hoses etc. The same applies to the A-4, and if
    you want to actually use the thing, or better yet, keep it to use for years, then it makes sense to modify the radio
    to work well instead of marginally acceptable. A stock Porche 911S will never keep pace with highly modified
    versions on the course, and so the story goes. I get that too.

    There is also the aspect that one must consider: The time invested in making the radio worthy of using.
    That is also another part of the hobby many of us enjoy, which involves the learning and doing process of making
    it a better more useful tool (toy) to enjoy... without too many expletives, Sound familiar?
    Obviously, not all of us have access to lab grade equipment and the experience in using said equipment to the
    degree where we can make profound decisions that result in the radio you described Carl. That is achievable
    for some but for many just a speck on the horizon.

    For me, I like a challenge and with the meager set of lab gear I own, am capable of slogging through such a project
    while allowing time for certain details to sink in and make sense before I measure twice and cut once.
    I really could care less about the vintage thing except for cosmetics, I/E no holes drilled in the face or badly
    thought out locations for circuit improvements. There are two other realities that exist in the vintage gear market
    that should be acknowledged when considering selling an A-4, Originality and performance.
    A Howard Mills restored piece can bring kilobuck returns, while a highly modified, high performance beast
    may not. But then, buyer motivation is the X-factor and that's where the truth lies every time.

    I wouldn't pay 2500 dollars for a HM radio because it would be a show piece that becomes a worry wart.
    Screw that. Give me a rat rod that barks the rubber in all 4 gears and makes the chicks turn their heads.
    I would love to have Rob Sherwood join this conversation. That would be interesting.
    More next week after I return from LA.

    Onward!
     
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  2. KM1H

    KM1H Ham Member QRZ Page

    AF6LJ likes this.
  3. KM1H

    KM1H Ham Member QRZ Page

    I wouldnt want a HM A4 either. It is too over restored and reminds me of all the trailer queens at car shows
    It was never a superb radio in any category except stability and dial accuracy. It is not a rare radio such as the SX-88 which IMO is far better looking and sounds great on AM. Id compare it to a 55 T Bird as both had a high price, limited market, and sales

    Current average prices on Fleabay are about the same or even less than a decent HRO-60, SP-600, etc. The A4 was a quickly marketed interim radio that had enough sales that it will never be called "rare". The companion KWS-1 was a poorly thought out product also and sold poorly while Hallicrafters HT-37 and various 32's sold like hotcakes, plus CE-100 & 200V's, to A4 owners.

    I never had a rat rod but below was my last street rod. A 26T on 28A rails, fenders and boards. A 2 1/2" dropped axle, supercharged 276" flathead, beefed C4 and a Ford 8" posi with Strange axles. Not chopped or channeled as there is little room inside even for a clutch pedal. Not a family car which was usually a 50's custom or later muscle car. Excuse the hokey bullet hole decals, the body as found had plenty real ones!

    26T4.jpg


    Vicky8.jpg

    I still have this

    68 Impala1.jpg
     
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  4. AF6LJ

    AF6LJ Ham Member QRZ Page

    I'm in love with your Black Beauty.
     
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  5. N6YW

    N6YW Ham Member Volunteer Moderator QRZ Page

    Speaking of "Black Beauty" of which all of them will be removed from the A-4 upon my return from
    LA this weekend. As to choice of replacements for the molded mica capacitors, does it really matter
    if I choose Silver Mica or Ceramic? Tolerance and voltage rating aside, is there a reason to make this
    choice significant?
    Beautiful cars Carl and thanks for sharing!
     
  6. AF6LJ

    AF6LJ Ham Member QRZ Page

    I would choose silver mica they are more stable.
     
  7. KM1H

    KM1H Ham Member QRZ Page

    Thanks for the comments Billy, Ive been a gearhead and a ham since I was a teenager.

    The 500V silver micas at Mouser and other respected national distributors is fine. The micas have a much higher Q for critical RF circuits

    I also had to rebuild the PTO about 25 years ago as the end points were way beyond the Cal knob and it was getting flakey/warbly due to bad caps inside. There are excellent on line write ups these days.
     
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  8. N2EY

    N2EY XML Subscriber QRZ Page

    In theory, no.

    In practice - I'd go with the silver micas where possible. Tolerance and voltage rating do matter. And - how much is really saved by using ceramic?

    ---

    I agree with you about keeping an old radio "stock". It really comes down to that one question: Do you want something to use, or something to look at?

    I'd add this: "How visible/reversible is a mod?"

    73 de Jim, N2EY
     
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    Both.

    Something to Smell too.
     
  10. N2EY

    N2EY XML Subscriber QRZ Page



    Sure - but sometimes you can't have both. Some parts just don't last forever.

    To a certain extent. There are good and bad smells from old radios......try to avoid the bad....
     

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