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I just purchased the Lace Alumitone Humbuckers set (black).
Here are the technical details for those interested.
Each magnet is: 1 3/32" long; 7/32" wide and 1/8" thick ceramic.
The metal frame of the pickup shell is also the two primary humbucking windings and it is also 1/8" thick. The magnets are glued to a plastic shelf which is also glued to the underside of the alumium shell. The magnets sit about even with the top of the alumium shell. There is very little string pull.
There is a transformer core that wraps around the alumium coil and core on one side. The other side seems notched to accomodate another similar transformer coil and core which would allow 4-wire traditional pickup coil switching. The transformer coil has two wires that are independent of the ground which allows series switching and phase reversal. The ground is connected to copper tape which is bonded to the aluninum shell under the center strip. This is the ground strip from which I obtained my capacitance measurements (below).
Each magnet is polarized North and South as it faces the strings.
The strings only pass over one magnet so the sound is rather "single-coilish" but is brighter as the DC resistance is lower but the inductance is rather high for these resistance values. Here are the critical measured values on my set:
Pickup 1: 3.40K ohm at 10.70H with 32pf coil lead to ground capacitance, 8.3 kHZ resonance (pickups alone, out of the circuit).
Pickup 2: 3.42K ohm at 13.24H with 24pf coil lead to ground capacitance, 8.7kHZ resonance (pickups alone, out of the circuit).
According to Jeff Lace these pickups were designed for 250K pot values for volume and tone, with either .02uF or .05uF tone caps (.05uF is the preferred value according to Jeff). I loaded one of these pickups down to about 150K ohms before I could hear the highs being noticeably cut.
These pickups sound a lot like active pickups with a low turns count of thicker wire using active electronics to restore the gain lost by the fewer wire turns.
My plan is to add an EMG BQC concentric bass and treble stacked control and the mid sweep and boost/cut concentric control to see how I can taylor the sound. The input impedance of this BQC module is 200K according to EMG and my examination of the input circuit component values.
These pickups are very quiet, even when sitting right in front of my computer. This key feature would indicate that they can be activly tone shaped without adding too much additional noise.
One interesting qualatative observation is that the Alumitones seem to have the upper harmonic structure that is typical of acoustic guitars which electric guitar pickups tend to mask with the sharp roll off past the resonance point. This is relevant of only string harmonics, not wood or body harmonics that is also present in acoustic guitar pickups.
I hope this answers some questions.
Joseph Rogowski
Here are the technical details for those interested.
Each magnet is: 1 3/32" long; 7/32" wide and 1/8" thick ceramic.
The metal frame of the pickup shell is also the two primary humbucking windings and it is also 1/8" thick. The magnets are glued to a plastic shelf which is also glued to the underside of the alumium shell. The magnets sit about even with the top of the alumium shell. There is very little string pull.
There is a transformer core that wraps around the alumium coil and core on one side. The other side seems notched to accomodate another similar transformer coil and core which would allow 4-wire traditional pickup coil switching. The transformer coil has two wires that are independent of the ground which allows series switching and phase reversal. The ground is connected to copper tape which is bonded to the aluninum shell under the center strip. This is the ground strip from which I obtained my capacitance measurements (below).
Each magnet is polarized North and South as it faces the strings.
The strings only pass over one magnet so the sound is rather "single-coilish" but is brighter as the DC resistance is lower but the inductance is rather high for these resistance values. Here are the critical measured values on my set:
Pickup 1: 3.40K ohm at 10.70H with 32pf coil lead to ground capacitance, 8.3 kHZ resonance (pickups alone, out of the circuit).
Pickup 2: 3.42K ohm at 13.24H with 24pf coil lead to ground capacitance, 8.7kHZ resonance (pickups alone, out of the circuit).
According to Jeff Lace these pickups were designed for 250K pot values for volume and tone, with either .02uF or .05uF tone caps (.05uF is the preferred value according to Jeff). I loaded one of these pickups down to about 150K ohms before I could hear the highs being noticeably cut.
These pickups sound a lot like active pickups with a low turns count of thicker wire using active electronics to restore the gain lost by the fewer wire turns.
My plan is to add an EMG BQC concentric bass and treble stacked control and the mid sweep and boost/cut concentric control to see how I can taylor the sound. The input impedance of this BQC module is 200K according to EMG and my examination of the input circuit component values.
These pickups are very quiet, even when sitting right in front of my computer. This key feature would indicate that they can be activly tone shaped without adding too much additional noise.
One interesting qualatative observation is that the Alumitones seem to have the upper harmonic structure that is typical of acoustic guitars which electric guitar pickups tend to mask with the sharp roll off past the resonance point. This is relevant of only string harmonics, not wood or body harmonics that is also present in acoustic guitar pickups.
I hope this answers some questions.
Joseph Rogowski
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