Re: Treble bleed mod for actives?
When designing pickups at Fishman, we're measuring things through a variety of different loads. There are a lot of things interacting that have to be unpacked before I can answer the different points here, sorry if it's long. First, everyone here is right when saying treble content of an active pickup with low output impedance isn't really affected by the volume control. There are other things that can be affected, like a general sense of presence and dynamics, but that's as much dependent on the first thing your guitar's signal hits, as it is the pickup design. So I'll leave that out of the discussion.
With passive pickups, the volume flattens the resonant peak as you turn it down, shifting it such that you lose treble long before you lose bass. The treble frequencies are the first to die on a standard passive volume control. We put the treble bleed in to leak some treble back into the signal as we're turning the volume down. The trouble is, the treble we bleed back in can't possibly mimic the sound of the pickup at full volume, because it's doing nothing to mimic the resonant peak and fall off. It's indiscriminately leaking treble content, more like the way a treble shelving EQ or a High Pass Filter would look on a scope. Many players still like it because they get the treble boosted while the output falls, thus the more sparkly "Clean" sound through a distorted amp. Everything we do with a HPF on a guitar is to massage and manipulate the effect to match the pickup, the player's expectation, the way they use it, their gear, etc. There is no magic bullet where you can have a spreadsheet tell you which capacitor and whether or not to use a supporting resistor, what value, etc.
If you try to put a HPF on an active pickup, since the volume knob isn't killing treble frequencies, you'll just be left with a pure treble boost (or bass cut) when you turn the volume down, which you very well might like! I would not like it personally, but I don't often play the kind of gigs where I have the guitar into a one-channel mid-gain amp, and have to control everything with the volume knob. AlexR is not correct, the capacitor value would not be the same. Its dependent on the impedance loads.
Now we get to active pickups and pot values. Since the pot resistance is primarily controlling amplitude, not altering resonant peaks or shunting treble, then the pot value has less of an effect on the tone but more on the volume. In Jeremy's case, its possible that too much EMG is, just too much EMG
The tone changes a little, but the volume pot taper changes too. It's awkward. All the volume is bunched up in one end of the travel.
Here's the interesting part: Since its dependent on the output impedance of the pickups, there are times when it makes more of a difference. EMG's traditional pickups have (I believe) a 10k output resistor. Whether you use a Vol/Tone, vs only a Volume, or no controls at all, the output changes. In the case of the X series however, (I believe) they use a 2k output resistor. This means the volume remains more constant regardless of whether you had 1, 2, or more potentiometers in the circuit. The Fishman Fluence have a 2k output resistor as well. So its more consistent. In A/B tests, however, you have to make sure you have the same number of pots in the signal path or you could be fooled into thinking one was louder than the other.
This could explain why some people use stock 250 or 500k pots with EMG's and are perfectly happy with the results, and for others it's terrible. It's all about the gain structure.
