Eric Daw's "Magic Harp Box" harmonica mic attenuator microphone pad pedal

Eric Daw’s  "MAGIC HARP BOX"  Harmonica Microphone Attenuator

 Feedback is the bane of all harmonica players who play through amplifiers.  This box allows you to use your amplifier to its full potential and get more volume with less feedback. It works with any harmonica mic and any regular guitar-style tube amplifier (not for an amp already modded or optimized for harp mic use.)  This device allows you to crank your amp up higher than you otherwise normally would be able to. This ensures that your amp is working hard, and delivering as much tone and sound as possible. You may also notice that the tone controls on your amp are more sensitive when using this attenuator.
 This is not a volume control, it is what is known as an "H" pad attenuator. This helps match the impedance of a typical harp mic to the impedance of a typical tube guitar amplifier. Guitar amplifiers were never intended to have a microphone plugged into the input, and the impedence mismatch that results is to blame for the howling feedback experienced when tried.  An “H” pad consists of five resistors made in the shape of an “H” laying on its side with the values calculated to achieve a specific attenuation of signal while maintaining proper impedance.  The middle resistor in the "H" pad in this instance is a potentiometer to give you some variance as you go from amp to amp and mic to mic. There is no battery, it is passive. It's handwired, with quality components, and built to last.
 With your amplifier on and turned up to the volume you want, set the knob on the Magic Box to zero, and gradually bring it up to the volume you need. If it feeds back, turn the knob on the box down a few notches. Even if the knob on the magic box is up all the way, the signal is still being attenuated. The beauty of this box is that it is fully adjustable with the attenuation knob, so that it can be optimized for any amp/mic combo. You will notice that different amp and mic combos will need different settings to achieve the best tone and volume. This allows you to bring your harps and mic somewhere and basically be assured that if you have to use a supplied amplifier, you can get a good tone and greatly reduce feedback problems.

What people are saying about the "Magic Harp Box"

"I have used the Magic Harp Box on many gigs, and it has become a dependable part of my on-stage setup. It allows me to achieve great tone and whatever volume the situation calls for—all without feedback.”
 -Kim Field, legendary harp player, band leader, and author of the book, “Harmonicas, Harps, And Heavy Breathers”

"It does help reduce feedback, and in providing some feedback control, it doesn't degrade the tone at a given volume setting of the amp, which is great. The advantage of being able to use your device on any amp is very valuable."
 -Brian Lee of "Brian Lee and the Orbiters" - pro harp player and recipient of the Washing Blues Society's 2019 "Best of the Blues" Award for Best Traditional Blues Act
  
"Highly impressed, not only did it reduce any feedback but what I love the most about your "Magic Harp Box" is the sound it gave me. Really pushed the sound to where it was breaking up the amp real good and sounded cool."
 -Dave Prez - harmonica virtuoso

“The attenuator works well. I sat in a 10’ X 10’ room, inches from my amp, turned on at full volume and there was no feedback. I noticed no loss of tone whatsoever!”
 -Daniel “Crash” Kowall - harmonica virtuoso

"This is a great pedal. I was concerned that it wouldn’t work with my hot hand made harmonica mics … I was wrong. Played through an Orange Crush 12. I loved it, my band loved it, and you’ll love it too. Thanks Eric Daw!"
-Dennis Hof

"Did some experimenting with your ‘Magic Harp Box.’ I was able to play at higher volumes without feedback compared to using the amp without the Box. This would be a really helpful device to get the best out of a surprise backline amp with which you’ve had no experience.” -David Littleford