Minimus speakers for Boatanchors

Michael Tauson wh7hg.hi at GMAIL.COM
Sun Feb 21 02:26:41 EST 2010

On Sun, Feb 7, 2010 at 8:49 PM, Chris Kepus <ckepus at> wrote:
> I recently gathered up 4 Minimus 77's (basically a Minimus but the case is slightly
> larger - woofers are the same size) at my favorite thrift for use in the ham shack
> and other areas of the garage.

The Minimus 7s have a 4" woofer while the 77s have a 5" which is why
the larger case.  Both use long throw woofers to make up for the lack
of size.  As built, both are decent speakers but can be improved
somewhat with a little effort, mostly with the crossover and surround.

There are several passive crossovers made to upgrade both versions but
there is also at least one site where you can calculate the component
values to build your own.  (I don't have the URLs but Google is your
friend.)  You'll have to open them up to determine the impedance of
the speakers themselves but that's not a large worry.

Fiberglas is commonly used inside the cabs however I dislike it
intensely so have used foam instead in the past ... but that's just
me.  One additional suggestion was to put soft modeling clay inside
metal cabs to deaden the cab itself by adding weight although it
wasn't clear if anything else was included.  This kind of reminds me
of how Audio Research made their speakers back in the good old days.
(Anyone who has lifted them knows what I mean.)

Several possibilties exist for speaker replacement (Again, Google is
your friend.) but there's a return on investment issue that may make
the effort questionable.  There's only so much that can be gotten from
bookshelf speakers in general before the net improvement is
negligable.  This is something I haven't pursued but you may want to.
I do know that ensuring the seal between the speaker mount and the
speakers is intact is important for proper functioning since they
depend on being sealed units - or as sealed as porous cones will

I think may be a good place to start regarding these
speakers.  Some of what I learned came from there.

> The initial receivers that got a Minimus were the 75A-4 and SX-100. The speakers
> sounded real good on CW, SSB, and AM. To my ears, the Minimus sounded just
> as good as the Collins speaker and the Hallicrafters P-23.

No doubt!  They have a wider range since they were designed for music
rather than communications.  I think they look better too but that's
personal opinion and worth pretty much what anyone's opinion is.  :-)

Best regards,

Michael, WH7HG
Hiki Nô!

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