Gonna jump in and attempt to build an effects box that will provide a better match up between the impedance level of my harmonica microphones with the input of any amplifier with the goal of bringing out the best tonal quality of each mic's element--in particular with crystal cartridges such as the Astatic MC151, but with possible improvements with controlled reluctance, controlled magnetic and ceramic versions also.
My buddy, Stephen Schneider is once again helping out the harmonica community by sharing just exactly what this little gizmo will do when it is plugged in between the mic and the amp. Go over to http://www.tedweber.com/ and click on the bulletin boards to get to the harp discussions and follow Professor Schneider's posts, especially the one on the Supro sound clips to hear the box in action. I was aware of just what this box would do from hanging out with him at Harmonica Organization of Texas (HOOT) meetings. He would bringing the box along and plug it into amps brought in by members and that he had never played before and manage to dial in a fatter sound with his mic that just didn't exist without the matcher. I was always amazed at just what a difference it could make. Many harp players have modified their amp's input resistance to achieve the same goal, but this allows for a plug and play with a tweak of a knob.
Now Stephen has provided us all with the schematic of what is called the Jayphat impedance matcher and it can be found by follow his posts over at the Weber harp board. I have started the process by ordering all the parts needed from http://www.mouser.com/ which are:
#512-MPF102-- 12 cents
2-Switchcraft Phone Jacks
10K Audio Potentiometer
Resistors were 1/2 watts & 10 cents each:
2-470 ohm resistors-#660-CF1/2C471J
10 ohm resistor-#660-CF1/2C103J
2-330 ohm resistors-#660-CF1/2C331J
Mallory DC film cap
Xicon Radial Electrolytic
2-Xicon Radial Electrolytics
So, if you want to tackle this little box and want to go through Mouser, then these order numbers should work. Several folks have responded over at the Weber harp board about this project with at least one harpman building it already and offering mod suggestions. I foresee that those posts will be very informative. I haven't received my parts yet, but Mouser is pretty darn fast, so I'll either have to put up or shut up. I post my progress as I go--maybe. I hate to expose my hacking skills and let them hang out for all to see.
P.S.--The good Professor Schneider reminded me that I didn't list isolation washers for the jacks that are needed to combat grounding loop hums and such. I didn't order the washers because I have some on hand from somewhere. I meant to mention that and knew that I needed to get back here and post it. He had sent me parts numbers for the washers a few days ago so here they are: 502-S1028 & 502-s1029--one of each for each jack. I also didn't order a switch, which I should have mention. Tons of choices there. Anyway--
The American Folk Blues Festival Volume 2
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