freefrog
Well-known member
Sequel of my last post this morning.
To put it in a simplistic way: a low inductance choke in a Q filter circuit wired to scoop the mids = a higher pitched resonant peak + a narrow mid dip + a loss of output level in the frequencies above the mid dip while the bass range stays unchanged.
It's a great circuit if we want pseudo acoustic tones from a high power Bill Lawrence L500. So great that I've a Q filter for such sounds in my own guitar with L500's...
But it's not the solution for a tight bass range + scooped mids IME/IMHO.
For that, IMHO/IME, the best tool would be a HIGH inductance choke like those found in vintage Gibson Varitones... and paired to a Varitone style wiring.
Here is a 5spice sim of the responses due to these two kinds of circuits, with a same P.A.F. style pickup (8k, 4H):
To be continued if time permits... Until a possible next post, let's just say that the "Varitone style wiring" above relies on a 7.5H inductor in series with a 100nF cap. The schematic to follow is just a simplified version of the Gibson Varitone, in which the rotary switch + RC package would be replaced by a single pot + a single capacitor (+ a 100k resistor in series with the pickup before this network, in order to obtain the response pictured above).
Depiction of a Varitone circuit with a high L choke, as it was still mounted in the Gibson Blueshawk recently (see p.6, the response of this circuit being pictured page 4):
https://blueguitar.net/new/schem/_gtr/blueshawk_circuitry.pdf
FWIW. I've passed a considerable amount of time on Q filters, Varitones and other passive circuits.
To put it in a simplistic way: a low inductance choke in a Q filter circuit wired to scoop the mids = a higher pitched resonant peak + a narrow mid dip + a loss of output level in the frequencies above the mid dip while the bass range stays unchanged.
It's a great circuit if we want pseudo acoustic tones from a high power Bill Lawrence L500. So great that I've a Q filter for such sounds in my own guitar with L500's...
But it's not the solution for a tight bass range + scooped mids IME/IMHO.
For that, IMHO/IME, the best tool would be a HIGH inductance choke like those found in vintage Gibson Varitones... and paired to a Varitone style wiring.
Here is a 5spice sim of the responses due to these two kinds of circuits, with a same P.A.F. style pickup (8k, 4H):
To be continued if time permits... Until a possible next post, let's just say that the "Varitone style wiring" above relies on a 7.5H inductor in series with a 100nF cap. The schematic to follow is just a simplified version of the Gibson Varitone, in which the rotary switch + RC package would be replaced by a single pot + a single capacitor (+ a 100k resistor in series with the pickup before this network, in order to obtain the response pictured above).
Depiction of a Varitone circuit with a high L choke, as it was still mounted in the Gibson Blueshawk recently (see p.6, the response of this circuit being pictured page 4):
https://blueguitar.net/new/schem/_gtr/blueshawk_circuitry.pdf
FWIW. I've passed a considerable amount of time on Q filters, Varitones and other passive circuits.
