MM Harpman Docs

Thank you for buying the MM Harpman Pedal!  It is an anti-feedback device and an active tone control specially designed to improve harp tone in amps. 

Guitar amps are often very bad harp amps.  Usually they have too much gain in their preamp circuits – causing screaming feedback – and not enough range in their tone controls – causing harsh tone. 

The Volume and Gain controls on the MM Harpman help you to take control of the amp by reducing the input level to the amp.  This allows you to turn your amp up higher to get that nice tube distortion and breakup before feedback.

The Bass and Treble controls on the MM Harpman are extensions of the tone controls on a guitar amp.  You can apply more high cut and more low boost to smooth out and fatten up your tone.


Power Source

You can power the pedal with a 9 volt battery or with a 9V power adapter.  I strongly recommend you use an adapter.  This pedal works pretty hard and the battery can run down after a few hours.  Remember, the LED is not a battery indicator; it is an on-off indicator.  The battery may have enough power to make the LED glow but not enough to drive the pedal.  When the battery is low the pedal will stop performing.  That is when you need to install a fresh battery.  For me, the 9V adapter is just a lot less hassle.

If you do use a battery, please remember to click the pedal off and remove BOTH cables from the pedal when you are finished playing.  This will preserve battery life.

We have 9V 2000mA power adapters for sale on our website for only $10.  They are very high quality and are powerful enough to drive your entire pedal board.

Hooking it Up

Plug your microphone cable into the “IN” jack on the right side of the pedal.  If your mic cable has an XLR connection you may need an inline impedance-matching transformer to convert your signal to high impedance.  No worries, it sounds a lot more complicated than it is.  Google it.  I use the Audix T-50K when I want to try a low impedance microphone.  Use a regular instrument cable to connect from the OUT jack on the pedal to the input jack on your amp.

If you use multiple FX pedals, make the MM Harpman the last in your pedal chain.
Setting Up the MM Harpman Pedal With a Guitar Amp:

1- Switch off the amp and pedal.  Plug your mic cable into the pedal and a cable from the pedal into the amp.

2- On the Amp – Set Bass on max, Treble on min, and Middle (if it has it) on 4.  (The typical harp setup on a guitar amp.)

3- On the Amp – Switch off any FAT button or Drive channel.  Set the volume on the amp to one third.

4- On the Pedal – Set the Bass on max, Treble on min, Volume and Gain on min.

5- Switch on the amp and pedal. 

6- On the Pedal – Increase the Volume while playing until you get a strong sound through the amp.  If the amp starts feeding back, reduce the Volume on the pedal until it stops.  If necessary, adjust the volume on both the amp and the pedal to achieve the biggest possible sound before feedback.

7- On the Pedal – Increase the Treble to get more cut and definition to the tone.   Use your ears.

8- On the Pedal – Reduce the Bass to eliminate muddy sound if any.  Use your ears.

9- On the Pedal – if possible, increase the Gain until the amp feeds back, then back it off a little.

This all sounds a little complicated at first, but it becomes simple after you do it a few times.  In only a minute or so your tone will be fatter with a lot less feedback. 

All players are different, as are all mics, amps, and rooms.  What works in one setting may need some tweaking in another.  Be prepared to occasionally fine-tune the pedal and amp.  Again, use your ears.  It’s easy.  This photo shows a typical setting, used in the video with the Fender Frontman 25 amp.


The MM Harpman Pedal  is warranted for one year to be free from defects in materials and workmanship.  This is a limited warranty that is void in the case of abuse or modification.  If you have an issue with the pedal, contacts us at
-Rick Davis
Memphis Blues Amps
51 Coffeen Avenue Suite 101-275
Sheridan, WY  82801

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