Dan Armstrong Yellow HumperVerified

From the post

Adding to Dan Armstrong library, The Yellow Humper bass booster. This layout is using two SPDT switches instead of the original setup. You could get closer to the original with using 2-pole On-Off-On switch, taking the ground to pins 2 & 5, Lo wire to pins 1 & 3, and finally Hi to pin 6 - leaving pin 4 unconnected. (info about the switch corrected 18.10.2019)

It is rather similar to the Purple Peaker, but was designed specifically with bass guitarists in mind. With the Humper, the musician can select a single 7 db peak or hump in the frequency response centered at 100 Hz to give his instrument a very solid bottom range in the" 1 " switch position. If he selects "2" 'he will get the same low end peak plus a 10 db peak at 2000 Hz to enhance his overtones and presence. Like the Purple Peaker, the Yellow Humper improves the signal even in the "Off' switch position due to its low 200 Output Impedance. The Yellow Humper was designed to let any bass. and many keyboards sound more powerful without be­coming rumblv or thumpy. Like the Peaker. it is excel1ent for use in recording. The Humper's input impedance is 100 k Ohms, and its Signal-to-Noise ratio is a very quiet 92 db.

According to discussion, the board works fine, but it is recommended to use a pot for volume at the output. 100K log will probably be ok. (board out to lug 3, new output from lug 2, lug 1 to ground)