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What To Do with an EB-63?

Discussion in 'Amateur Radio Amplifiers' started by AD6KA, Apr 13, 2012.

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  1. AD6KA

    AD6KA Ham Member QRZ Page

    Quite a few years ago I built an EB-63 SS amp (~140w)
    from CCI (2 X MRF 454). The intention was to use it
    with various CW, PSK and SSB QRP rigs. I built the
    K5OOR "100 watt Low Pass Filter Board" kit, but really,
    those inductors are just too small, too close together,
    and get wayyy too hot. It's really not for 100w use.
    But there are other LPF boards and circuits out there
    for me to research.

    But much more importantly, I have since learned from reading these
    amp blog boards that the EB-63 is not linear, has no real
    bias control circuitry except a big clamping diode, operates
    strictly Class C and has horrible IMD performance. (I have
    learned a lot from reading the "gurus" on these boards.)

    So...what am I to do, if anything, with this amplifier?
    IS THERE a way to build in proper bias control, or should
    I just say "Lesson learned, oh well", throw in the towel,
    and use the parts for a better amplifier design?
    Just operate Class C CW? (With the proper LPFs of course).
    Would the IMB be acceptable at lower power, say 50w?
    (I have no equipment that could test this)
    I'd never sell it to a non-ham or CB'er, and probably not
    even to a ham who doesn't plan on fixing the IMD issue.

    Suggestions? Ideas for a good bias control circuit to add?
    Or chock it up to lesson learned and start over?
    TNX ES 73, Ken AD6KA

    EB63-A.jpg EB63-B.jpg
  2. AC4LJ

    AC4LJ XML Subscriber QRZ Page

    Ken, I have been bitten by the bug to build a solid state amplifier. Choices seem limited, but I have been looking at the amp described in Motorola's AN 762. This appears to be the same amp as the eb63 with improved bias control. The problem I now find is availbility of parts .... This may be taking the thread off topic, but may show you an option. 73 Tony AC4LJ
  3. AD6KA

    AD6KA Ham Member QRZ Page

    Thanks Robert:

    Yes, it looks like the AN-762 is what I should have bought
    in the first place!
    :mad: Since a friend with a machine shop made,
    drilled, and tapped a nice heat sink and sheet metal "Fan Air
    Flow Director", it sure would be nice if the AN-762 PC board
    lined up with, the mounting holes on the EB-63. (Or at least
    left me room to drill and tap new holes).

    Oh, and an FYI to those thinking of buying an EB-63:

    What CCI is now shiping is the EB-63A. You do NOT get
    what you see in the photo or description on the CCI EB-63 web page

    They charge you for a large DPDT open frame relay, but you get a
    small $3 PC board mount relay. Also the board layout and schematic
    are slightly different, and the traces on the board much, much narrower.

    I don't have one of these "EB-63A's" but have seen good photos.
    I wonder what OTHER changes CCI has made to their products
    that they are not revealing on their website.

    Oh well, live and learn. I just wish There was a good "bias fix"
    for this amp without having to rebuild the entire amp.......
    but as the old saying goes "If wishes were horses, beggars would ride!".

    tnx agn es 73, Ken AD6KA
  4. W9GB

    W9GB Ham Member QRZ Page

    Last edited: Apr 13, 2012
  5. AC4LJ

    AC4LJ XML Subscriber QRZ Page

    Greeting all .... FoxDelta is sold out of these "kits" with no plan to re stock. CCI is apparently no longer in business. Where's a feller to go? any ideas Tony AC4LJ
  6. W9GB

    W9GB Ham Member QRZ Page

    TONY --

    I would HIGHLY suggest you check your facts, before stating the business status
    of an amateur radio dealer.
    Your statement about Communication Concepts, Inc. (CCI) is INCORRECT.
    I just got off the telephone with CCI, and they were not happy reading your statement on QRZ.

    Communication Concepts, Inc. (CCI) IS OPEN for business.

    For further information or to place an order please contact CCI via the following methods.
    Telephone: 937-426-8600
    Fax: 937-429-3811

    Communication Concepts, Inc.
    508 Millstone Dr.
    Beavercreek, OH. 45434-5840

    The ARRL Handbooks and Motorola Application Notes have Helge Granberg's work and PC board layouts. However, these designs and components are ~ 30 years old.

    Newer RF transistors (LDMOS) have been introduced by Freescale (an old Motorola division), but boards, and kits are not yet available or offered.

    IF you desire solid-state, the Elecraft KPA-500 Kit provides an excellent solution for $2,000 USD

    For cheaper, you are left with repairing (restoring, or scrounging) older tube and solid-state designs.
    Last edited: Apr 13, 2012
  7. K1ZJH

    K1ZJH Ham Member QRZ Page

    Quote: I'd never sell it to a non-ham or CB'er, and probably not
    even to a ham who doesn't plan on fixing the IMD issue.

    What do you want for that board? I might be interested in attempting to save it.

    Pete k1zjh (amateur extra and FCC 1st class radio)
  8. KO6WB

    KO6WB Premium Subscriber QRZ Page

    If the amplifier is truly running in class C you can operate it on more modes than just CW. You can run RTTY and Data and of course FM. Any mode that has 100% duty cycle is okay on a class C amplifier.
    The modifications to bring an EB-63 to full linear operation isn't that much of a change. Do as Greg has suggested and use the bias network out of the ARRL Handbook. You can make it on a small seperate board and just tie it into the base circuit of the EB-63.
  9. AC4LJ

    AC4LJ XML Subscriber QRZ Page

    World... I aploigize to CCI and all on the forum. CCI is intact and doing well. I just ordered (over the phone) the AN 762 amplifier kit. The problem was internet involved. Thanks for bringing this to my attention, W9GB, All is well now Tony AC4LJ
  10. AD6KA

    AD6KA Ham Member QRZ Page

    Thanks for all the great advise guys!
    Sounds like a plan, if I can pull it off without toasting those 454's.
    I dunno Peter, lemme do some bias circuit research advised by
    the other helpful fellows. The one in the photos is perfectly
    laid out to easily drop into an enclosure with another project.

    However I have an even older EB-63 already mounted in a decent enclosure
    with a breezy squirrel cage fan and a 25A circuit breaker switch.
    I might let that one go more easily. Haven't checked it out it in years but
    it should work FB. (It too is without LPF's).

    But I will keep your email in case or when, I decide to let it go.
    73, Ken AD6KA
  11. W9GB

    W9GB Ham Member QRZ Page


    A small Radio Shack perf board should handle regulator and parts for EB63 bias supply.

    When Helge designed the original Motorola AN-762 board, he used the "round can" (TO-100) package
    LM-723H regulator which was very common in early 1970s -- especially for 1960s transistor designers!

    The Dual In-Line (DIP) was the "computer" and 7400 style package -- that LM-723 package became the de facto standard regulator for US designed linear power supplies (Astron, others).
    Tony --

    Here is your Inspiration Link (CCI AN-762, MRF-454 140 watt board) by G3TSO

    Mike Grierson, G3TSO has homebuilt much of his equipment.
    He has won the Ostermeyer Trophy TWICE, awarded for Radio Communication Technical Article.
    Last edited: Apr 14, 2012
  12. AD6KA

    AD6KA Ham Member QRZ Page

    Thanks Tony:
    That is a very sweet amp that G3TSO has built around the AN-762 board.
    I also like the LPF Network all on one board.
    wish I could find even the PC Board for that project....

    Easy for you to say.:D I am MUCH more of a kit builder (Board Stuffer)
    than a Homebrewer and would need an Elmer or close guidance for
    a project like that. Hell, I don't even own a drill press to make the
    enclosure openings properly (If I need large or odd shaped ones).
    .I usually end up going to a vocational school or high school
    Metal Shop class and having them do the work for donations or pizzas!

    The $64,000 questions is.....
    Do I have the technical chops to make the conversion from an EB-63?
    (Uh,frankly I don't think so) Or should I buy most of the
    AN-762 parts that I need and strip the rest from the EB-63?
    Seems a shame to tear up a working amp, but ya gotta do what ya gotta do.

    Or I guess I could unload some stuff hanging around the shack
    gathering dust and buy & build the AN-762, hopefully with a G3TSO
    bias mod... while looking for a good LPF network board with relays.

    I have read several posts (forget where) that CLAIM that the CCI
    individual band LPF filters don't perform all that well, and
    are alo difficult to design a switching arrangement around.
    (NOTE: I READ THIS, I do NOT know if it is true or not, OK?) :cool:

    Well, you've all given me a lot to think about....thanks.
    Would operating the EB-63 at greatly reduced power level,
    say 50 or 60 watts out, improve or DEGRADE the IMD performance?

    TNX AGN ES 73, Ken AD6KA/5R8GQ
  13. KO6WB

    KO6WB Premium Subscriber QRZ Page

    Operating the EB-63 at a reduced power level and with a slightly higher voltage will reduce the IMD somewhat. I'm not sure this will work at the 50W level. The bias applied to the transistors will still have the same problem until you replace the bias circuit.
    Now, homebrewing can be challenging but it is also rewarding. What you should do is build the 723 based circuit as outlined and before you install it, run it through a testing run. If everything responds as it should then you did make it correctly and it can be installed. The cost of the parts isn't much so you have very little to lose.
    Hope this helps
  14. W9GB

    W9GB Ham Member QRZ Page

  15. AD6KA

    AD6KA Ham Member QRZ Page

    I've built and own that K5OOR "100w" LPF board.
    There is no way that board should be rated for 100 watts unless
    you make 15 second transmissions with 30 second intervals.
    The board is 2.25" X 4.5" and has 14 toroidal inductors, 33 caps
    and 12 relays all scrunched together. The thing gets incredibly hot,
    (touching an inductor will literally burn your finger) even when running at
    50 watts lower power and for short duration.

    Customer support:
    I checked input SWR on all bands and found it almost 3:1 on 80m.
    When I wrote K5OOR and asked for some troubleshooting
    tips to fix this situation he just replied "That's Impossible!".
    Makes me wonder why he is putting out VERSION FOUR of his "HF Packer Amp". :rolleyes:

    It works OK at 50 watts on all bands but 75/80.
    It's sitting in my junk box if anyone wants to make an offer......
    73, Ken AD6KA
  16. W9GB

    W9GB Ham Member QRZ Page


    The OM6BPF Six band pass filter is an interesting product, supposedly rated for 200 watts RF.

    It would be an interesting conversation with OM Power, since that is HALF of a solid-state
    HF amplifier (contains the band switching interface for automatic operation with many HF radios).

  17. AD6KA

    AD6KA Ham Member QRZ Page

    Thanks for the excellent tip Greg!
    It looks like exactly what I need.
    (Though I will still have to install a proper bias circuit for IMD problems)
    I'm just waiting for a price w/shipping quote from the manufacturer.
    73, Ken AD6KA

    Attached Files:

  18. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    What IMD problems?

    The EB-63 is biased for linear operation by design. The Motorola Bulletin clearly displays IMD performance and even plots it vs. frequency and output power.

    IM3 at 100W is -38 dBc; at 150W is -29 dBc
    IM5 at 100W is -45 dBc; at 150W is -40 dBc

    Have you looked at the spectral displays and graphical plots in this:

    It's as clean as the PA section of the 100W HF transceivers on the market.
  19. WA6MHZ

    WA6MHZ Premium Subscriber QRZ Page

    I am hoping someone will have a 100W 80-10 PA kit at Dayton for an affordable price. Have never heard of a EB-63. I need some BOOTS for my Yaseu FT-817 to turn it into a REAL radio!
  20. AD6KA

    AD6KA Ham Member QRZ Page

    Thanks for the info Steve. I had not seen those
    graphs and numbers before.
    I built the thing several years ago, then read a thread
    on Eham where quite a few people trashed it and said that it was
    not suitable for use on the ham bands, that it was basically
    a CB amp.
    Thanks for proving me wrong, this is very encouraging!

    By the way Steve, Steve, did you ever get my emails I sent to your listed addy re my AL-80A?? (Discussion from another thread..)

    Thanks es 73, Ken AD6KA
    kenp (at)

    PS: YIKES! Just got an mail from the manufacturer that
    this LPF network mentioned previously costs $870 USD shipped to USA.
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