Looking at a COLLINS 75A4 RECEIVER , need advise

Discussion in '"Boat Anchor" & Classic Equipment' started by KB4MNG, Jun 14, 2019.

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  1. KB4MNG

    KB4MNG Ham Member QRZ Page

    One has come up for sale close to where I live, asking price $1035. I've owned various BA receivers through the years and collins in on my bucket list. From the pic, looks very clean and has not been recapped.

    Just not familiar with the Collins line. Is it worth the asking price. How is the performance, are they hard to for the user to align and work on? What would you offer?

    thanks kb4mng
  2. KB4MNG

    KB4MNG Ham Member QRZ Page

  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    Price seems OK. Looks like it has Extra filters ?

    It is hand built and easy to work on.
  4. K5UJ

    K5UJ Ham Member QRZ Page

    That price is way too high these days. That was what folks were asking several years ago. An A-4 like the one in the photo nowadays is usually priced around $400 less than the price you gave.
    KK4NSF, WB2GCR and W7UUU like this.
  5. WA5VGO

    WA5VGO Ham Member QRZ Page

    Looks like a late serial number. Doesn’t really add anything to the performance, but does cause the price to go up. Asking price seems very steep. I’d say $500-600 in that shape. Add $100 each for any additional filters.
  6. N2EY

    N2EY Premium Subscriber QRZ Page

    Why not do some....research?

    The manuals (there are several revisions) are online, for free download. If you are an ARRL member, the product review article is available (April 1955).

    And much more.
    W7UUU likes this.
  7. N2EY

    N2EY Premium Subscriber QRZ Page

    Why not do some....research?

    The manuals (there are several revisions) are online, for free download. If you are an ARRL member, the product review article is available (April 1955).

    And much more.

    If it has not been recapped......the price should reflect that.
    W7UUU likes this.
  8. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    There is really no way to tell the serial number without actually looking.

    The "going price", of 75A-4 receivers, is highly dependent on the serial number with a high serial number receiver often being valued at twice a mid range serial number is valued and even as much as 3-times what a low serial number unit would bring.

    If the serial number is in the 5XXX range, the price is fairly reasonable especially if there is more than 1 filter installed. However, as the serial number range goes lower, so does the value.

    One thing is that the condition of the paint is not all that good and, as such, in any serial number range the value is going to be between $50.00 and $100.00 lower.

    I would have to know the serial number plus see the inside of the receiver before offering any real advice on what it is worth. Also, have all the "black beauty" capacitors been replaces as well as the "deadly capacitors"? If not, then the value is going to be about $100.00 to $150.00 lower because it will cost at least $100.00 to have those parts replaced. If you do the work yourself, then about $25.00 in parts cost.

    Frankly, too many variables to give you an immediate estimate.

    Glen, K9STH

    technical adviser-1a.jpeg
    W1TRY likes this.
  9. KA9JLM

    KA9JLM Ham Member QRZ Page

    The price could also go down if the caps have been replace by a butcher. :eek:

    I would rather have a virgin. Then I know what has been done, And that it was done right.
    W1BR and K9ASE like this.
  10. W1NB

    W1NB XML Subscriber QRZ Page

    I agree with Glen. There are too many unanswered questions to give an accurate valuation. If you’re able to do repairs yourself an unmolested radio is the best way to ensure you’re not buying someone’s butcher job but if you’re not so inclined you’ll want to buy from a known, trusted source. Here are some of the value impacting variables:

    1) modifications to the circuitry. This is common in the front end and can very dramatically effect sensitivity, selectivity and AGC. Confirm the correct tube compliment is being used and look to see if wiring changes and components have been changed. This will usually be obvious at solder points.

    2) What filters does it have? the 75A-4 is a very nice AM receiver but you’ll need the AM filter installed. Similarly, listening to SSB with the AM filter will be pretty rough. Either original Collins or Dave Curry filters should be OK but check operation on all modes for which filters have been installed to ensure they’re all good. And some operators have installed modified R390 wide filters for AM. They work OK but are really wide so operation under busy band conditions can get rough. I recommend staying with the appropriate 6KHz filter for AM, 3.2 KHz for SSB and 800 KHz for CW. The 1.5 KHz, in my opinion, is worthless.

    3) Does it have the 4:1 ratio reduction tuning knob? Without it it’s much harder to smoothly tune, especially narrower bandwidth signals like SSB and CW.

    4) Have the Black Beauty capacitors been changed and DC blocking capacitors added to protect the mechanical filters. The Black Beauties did not pass the test of time. They’ll leak and short, eventually resulting in total failure and, usually, component damage.

    5) Is the audio output transformer original or has it been replaced? Although I’ve not experienced a transformer failure I recall that it’s not uncommon and a NOS or close replacement may be hard to find. I think there has been a tendency by some hams to force fit something which can result in a hack job. I’ve also seen hams replace some of the tubes with Tubesters, especially the audio output tube. That’s not necessarily a bad thing, it does have some benefits, but if you want authenticity you’ll want to stick with vacuum tubes.

    6) Has the cabinet been resprayed with standard paint. The St. James gray has a unique light textured look and feel and, in my opinion, is most desirable to maintain authenticity.

    Keep in mind that 75A-4s are about 70 years old so some replacement parts are getting a bit tough to find. They are, though, a very nice receiver and perform well if they’re in good condition.

    Good luck,

    Scott, W1NB

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