re: "magic box"

["G." <gigs@xxxxxxxxxxxxxxx>]

<quote>
Date: Fri, 30 Apr 2004 16:26:12 -0400
From: "Smith, Richard" <rismith@xxxxxxxxxxx>
Subject: "magic box"

I'm interested in the Holmes "HARP COMMANDER", but the price is
absolutely outrageous.  Is there any real reason why it shouldn't cost under
a $100, like a typical guitar stompbox?  Does anyone know where to
find schematics/plans for a similar type box, that one can build oneself?
I've seen a plan for Iron Mike Curtis' "MIKE MOJO" box, but frankly the
plan appears to be incomplete.  The only component shown is the Op-Amp
itself.  A feedback loop is shown, but no resistors or anything.
Oh well, it's worth asking; any help would be appreciated.

Richard J. Smith, R.A.
rismith@xxxxxxxxxxx
</quote>

Each Harp Commander is hand made by Ron Holmes - he's definitely not getting
rich doing this. His price is very reasonable considering what you get for
your money.
He put a lot of thought and research into its design from the case its
installed in to useful features to redundant circuitry to protect it if you
subject it to up to 50volts DC.

It isn't just a class A preamp setup specifically for harmonica (with gain,
bass and hi-cut) which in itself is great - it has an RF filter, a built in
compressor effect, a phase invertor, as well as impedance matching for all
high impedance harmonica microphones, AND two outputs for line signal and
guitar signal which can both be used at the same time making it a very
versatile and useful unit for a number of reasons.  I am delighted with mine
and have no intention or need to buy another tube amp, as the harp commander
fills my tonal needs.   I can pop it in my pocket with a battery pack, and
take a mic and my harps to a gig, plug in and go - scalable to any size
venue so long as you have a decent PA or amp on hand.

I have a customer who's a professional player who uses his Harp Commander
with a Bassman RI and has no trouble with feedback, and for some gigs and
studio recording he leaves the amp at home relying on the Harp Commander
alone.

I don't know of any other device of this size with this much functionality
made specifically for harmonica for the same price.  $279.95
http://tinyurl.com/yuz6q
ACCESSORIES -> COMMANDER

Kinder offer a couple of harmonica specific devices, in addition to their
custom harmonica amplifiers.    http://www.kinder-instruments.com/pg1.html
The Anti-Feedback+ unit for mitigating feedback for US$359, and the
MidBass-Cut unit for US$240.00, they have another device for providing your
mic with additional power to aid its tone.  I don't have any experience with
Kinder's devices - but from the descriptions on Kinder's site it would
appear you can get everything these two units offer from one Harp Commander.

Mike's MOJO unit is an impedance matching device, that is all - he put it up
because he enjoys sharing his knowledge, and was regularly answering
questions about matching impedance, so he put it up, and offers to make one
for you for a nominal fee - matching impedance alone can solve a bunch of
problems harp players complain about.
Have you given Mike a chance to explain his schematic?  Have you tried
asking him?

There are a few cheap Tube Preamps on the market for around US$100 give or
take US$50 - They're mostly designed for guitar or vocal mics.  Behringer's
is very inexpensive for around US$60 new.  One harmonica player has touted
its usefulness.
But they're just tube preamps with a few dials - and with these you get what
you pay for.

I spent a few months filtering through people's reviews and experiences with
various units, and decided in the end I was better off buying a second harp
commander.
They don't suit everybody's taste, but I'm very happy with both of mine, no
regrets.

YMMV.
- -- G.