Post by antigua on Mar 23, 2018 23:10:09 GMT -5
This isn't exactly pickup specific, but if there's one thing that is made clear from pickup analysis, it's that the pickup is really a part of the overall resonant circuit formed between the guitar, the guitar cable, and whatever else in between the pickups and the first signal buffer.
One of the issues of passive guitar pickups is that the guitar cable's capacitance combines with the resonant peak of the pickups. Passive guitar pickups can become dark if the guitar cable is overly long, or of poor quality, causing a higher capacitance per foot of guitar cable. One of the advantages of a buffered effect pedal is it terminates the resonance circuit between the pickups and guitar cable, where as a true bypass pedal caries it out that much further.
This issue has led to, among other things, the necessity of active pickups like EMG, on board pre amps or the "zero cap cable" zerocapcable.com/?page_id=231 (a cable with a pre-amp built in).
So aside from all that, there is a very nifty wireless unit from Line 6 called the G10 Relay, which is awesome because you don't need no freakin belt pack, the transmitter is small enough to integrate with the male 1/4" jack line6.com/relay/g10 :
So this prompts (but does not "beg) the question: how much capacitance combines with the pickups when you used this tiny dongle? How does it compare to a guitar cable?
Using an SSL-1 as a test subject, with an inductance of 2.54H (as measured at 100Hz with an LCR meter), I created bode plots with a) no cable b) with the Relay G10, c) with a 470pF test load:
This plot shows the impedance of the SSL-1 under these three difference circumstances. The peaks are where the inductance, and capacitance of the pickup and the guitar cable (or test load or wireless unit) combine to create a maximum impedance, and then beyond the peak the capacitance causes the impedance to drop away.
Therefore, knowing the peak frequency and the inductance allows the net capacitance to be determined, and it works out to be this:
No load: dV: 17.4dB f: 9.06kHz Capacitance: 111pF
Through Relay G10: dV: 11.5dB f: 6.43kHz Capacitance: 231pF
With 470pF & 200k ohms: dV: 7.2dB f: 3.94kHz Capacitance: 632pF
A typical guitar cable produces about 40pF per foot, so a 10 ft. guitar cable produces about 400pF capacitance overall. As a test load, I use 470pF since this is a standard capacitor value that comes close enough for approximation purposes.
It can be seen that the Relay G10 add only 120pF of capacitance to the SSL-1 (this difference between 111pF and 231pF). Relative to a guitar cable, that's very very low capacitance. It's equivalent to using a three foot patch cable.
The resonant peak of most Strat pickups with 470pF loads is in the area of 4kHz. With a load of only 120pF, the peak will be closer to 7kHz. The resonant peak of PAFs, like a 57 Classic, is closer to 2.5kHz with a 470pF load. With only 120pF added capacitance, that peak would be pushed up to around 5kHz. This essentially pushes the resonant peak past the frequency range that most guitar speakers operate the most efficiently within, which means the treble become flat, or more clear sounding, without a resonant "hump" that often comes across as a nasal tone, or a "honk".
Long story short, if you find appeal in low capacitance, or "zero cap" guitar cables, or if you like active pickups for their open and airy top end, you might appreciate the Relay G10 wireless unit for its tonal benefits.
Conversely, if this is a quality you dislike about the Relay G10 (or other wireless units), you can restore a high C tonality by putting a 240pF (or more, or less) across the input of the guitar in order to lower the resonant peak, as you would with a typical guitar cable.
As an aside, it can also be seen that the Relay G10 has a slightly lower peak amplitude than the no-load peak. The "no load" peak actually has a 1meg input impedance, so it appears the the Relay G10 has a slightly lower input impedance than this. This shouldn't have too noticeable of an impact on the tone, as the volume and tone controls in the guitar load the pickup down to a far greater degree, which is simulated with a 200k ohm resistor in the test load (the red line).
One of the issues of passive guitar pickups is that the guitar cable's capacitance combines with the resonant peak of the pickups. Passive guitar pickups can become dark if the guitar cable is overly long, or of poor quality, causing a higher capacitance per foot of guitar cable. One of the advantages of a buffered effect pedal is it terminates the resonance circuit between the pickups and guitar cable, where as a true bypass pedal caries it out that much further.
This issue has led to, among other things, the necessity of active pickups like EMG, on board pre amps or the "zero cap cable" zerocapcable.com/?page_id=231 (a cable with a pre-amp built in).
So aside from all that, there is a very nifty wireless unit from Line 6 called the G10 Relay, which is awesome because you don't need no freakin belt pack, the transmitter is small enough to integrate with the male 1/4" jack line6.com/relay/g10 :
So this prompts (but does not "beg) the question: how much capacitance combines with the pickups when you used this tiny dongle? How does it compare to a guitar cable?
Using an SSL-1 as a test subject, with an inductance of 2.54H (as measured at 100Hz with an LCR meter), I created bode plots with a) no cable b) with the Relay G10, c) with a 470pF test load:
This plot shows the impedance of the SSL-1 under these three difference circumstances. The peaks are where the inductance, and capacitance of the pickup and the guitar cable (or test load or wireless unit) combine to create a maximum impedance, and then beyond the peak the capacitance causes the impedance to drop away.
Therefore, knowing the peak frequency and the inductance allows the net capacitance to be determined, and it works out to be this:
No load: dV: 17.4dB f: 9.06kHz Capacitance: 111pF
Through Relay G10: dV: 11.5dB f: 6.43kHz Capacitance: 231pF
With 470pF & 200k ohms: dV: 7.2dB f: 3.94kHz Capacitance: 632pF
A typical guitar cable produces about 40pF per foot, so a 10 ft. guitar cable produces about 400pF capacitance overall. As a test load, I use 470pF since this is a standard capacitor value that comes close enough for approximation purposes.
It can be seen that the Relay G10 add only 120pF of capacitance to the SSL-1 (this difference between 111pF and 231pF). Relative to a guitar cable, that's very very low capacitance. It's equivalent to using a three foot patch cable.
The resonant peak of most Strat pickups with 470pF loads is in the area of 4kHz. With a load of only 120pF, the peak will be closer to 7kHz. The resonant peak of PAFs, like a 57 Classic, is closer to 2.5kHz with a 470pF load. With only 120pF added capacitance, that peak would be pushed up to around 5kHz. This essentially pushes the resonant peak past the frequency range that most guitar speakers operate the most efficiently within, which means the treble become flat, or more clear sounding, without a resonant "hump" that often comes across as a nasal tone, or a "honk".
Long story short, if you find appeal in low capacitance, or "zero cap" guitar cables, or if you like active pickups for their open and airy top end, you might appreciate the Relay G10 wireless unit for its tonal benefits.
Conversely, if this is a quality you dislike about the Relay G10 (or other wireless units), you can restore a high C tonality by putting a 240pF (or more, or less) across the input of the guitar in order to lower the resonant peak, as you would with a typical guitar cable.
As an aside, it can also be seen that the Relay G10 has a slightly lower peak amplitude than the no-load peak. The "no load" peak actually has a 1meg input impedance, so it appears the the Relay G10 has a slightly lower input impedance than this. This shouldn't have too noticeable of an impact on the tone, as the volume and tone controls in the guitar load the pickup down to a far greater degree, which is simulated with a 200k ohm resistor in the test load (the red line).
