Please share your thoughts on how it goes!
In the interest of some clarity, to what I was talking about. (I was working off memory, but knew I had a solid avenue to proceed.)
I went to the source @ Stellartone:
Thanks for your question. This is a very interesting subject (to me) so please excuse this verbose reply!
Volume - Blend - ToneStyler / 2 Pickup Bass
"100% + 100%" in the center detent.
However, there is no "80%-20%" mix at the extremes of rotation...
It's always "100%-0%". If the pot is wired normally, with each deck grounded, one pickup will reach zero volume at either end of rotation - while the other pickup stays at 100% volume, from the center detent to the end of rotation.
MONO BLEND POTS, which is the type under review, are built with linear taper on 1/2 of rotation of each deck. The other half is not made of a carbon resistive strip, but is instead made of solid copper foil. So, there is zero change in loudness across 1/2 of rotation of each deck, followed by a 100% - 0% linear change in volume on the opposite 1/2 of rotation.
There is a lot of misinformation on the internet regarding "blend pots", "pan pots" and "balance pots". All of these devices are not "the same but with different names". They do not perform the same tasks! I'll suggest that widespread confusion about the differences between these three types of dual-deck pots has caused the majority of published misinformation.
Please be confident that installing a Bourns MONO BLEND POT is the
right solution to controlling a pair of passive pickups in a guitar or bass! When set to either extreme of rotation, and in the center detent, a MONO BLEND POT will duplicate the function of a Switchcraft 3-way toggle switch: solo neck PUP at 100% volume... BOTH PUPS at equal 100% volumes... and solo bridge PUP at 100% volume. Only when set to any intermediate position between maximum and center will you hear an uneven blend. The important factor is that the blend will ALWAYS connect one pickup at 100% volume... with the other pickup blended in any loudness between 100% and 0%.
In other words, it's totally impossible to dial in a 80% + 20% mix. However, if the goal was simply to achieve a 4:1 loudness ratio, that would be accomplished by setting the knob slightly off-center, to produce THIS RATIO:
100% + 25%
The beauty part of using a MONO BLEND POT? Since at least one pickup is constantly connected to the master volume pot's input lug at 100% volume, this means there is NEVER any resistance between one pickup and a master tone pot, such as a ToneStyler wired to the blend pot's output / master volume pot's input. The absence of any resistance creates the perfect tonal connection between the tone control and the louder pickup; this will be heard at all blend levels and all master volume levels.
CONVERSELY... if a STEREO PAN POT was mistakenly installed in a bass, the ToneStyler would not work at full strength in the center "both pickups" detent, because that pot is
not designed to produce zero ohms to both channels in the center. Pan pots are designed for an entirely different task: maintaining constant loudness in a mixing board channel, as the source is "panned" from maximum left, to center of field, to maximum right. If the pot produced zero ohms to both left & right speakers in the center notch, the source would become
twice as loud when panned to the center, since both speakers would be receiving the same full-volume signal.
The STEREO PAN POT solves this engineer's dilemma by never reaching zero ohms on both channels at once, when set to the center. For example, one common type of pan pot used in mixing boards only reaches 70.7% loudness on both channels simultaneously in the center detent... because 70.7% loudness + 70.7% loudness = 100% loudness... that's the same 100% loudness heard, if panned fully left or right. As a result, the engineer can literally "walk" the musician's mono sound source from the far left speaker... to the "center" between the speakers... to the far right speaker in the stereo sound field... without ANY CHANGE in loudness. It's quite clever!
However, this is the exact opposite of what's called for in a bass. Instead of one signal being sent to two speakers, you have two signals sent to one speaker. If a pan pot was used in error, the center "both pickups" loudness would be considerably lower than either soloed pickup. So, to produce the desired equal loudness no matter how the two pickups are combined, you need a MONO BLEND POT. Only the tone should change as the two pickups are blended!
I hope this answer is informative, and not too confusing! Let us know if you have any questions during your upcoming tech session? Have a great week -
Best regards,
Don Campbell