I initially intended to fit three Burns Mini Tri-Sonic pickups to the guitar as I did on the 3/4 scale ‘1975’ Red Special project in 2013 so I ordered a set from Barry Gibson of Burns London. On receipt, I measured the various electromagnetic characteristics of this set using a Peak Atlas LCR45 meter (see data below) and found that they were considerably different to the set I had previously bought. The DC resistances (DCR) of the 2013 set were: neck and middle both 7.20 kOhm and bridge 7.80 kOhm. I didn’t measure the inductances or other E-M parameters. Therefore, I returned the Mini Tri-Sonics and requested a replacement set of standard size Burns vintage Tri-Sonics. I measured the electromagnetic characteristics of the replacement set (see data below) and found them to be significantly different to the set of Adeson “original BM/Guyton specification” values I had bought retail for my Red Special project so I sold these on eBay.* Note the error in the wiring diagram in the image gallery below. The green wire is the casing earth, not the coil negative which is the black wire.*

Burns London 2018 Mini Tri-Sonic Pickups Characteristics

Neck

DC resistance: 8.47 kΩ

Inductance: 0.71 H

Impedance: 9.08 kΩ (j 4.4 kΩ)

Total magnitude of impedance: 10.11 kΩ (phase angle of impedance vector: 26°)

Middle

DC resistance: 8.55 kΩ

Inductance: 0.71 H

Impedance: 9.18 kΩ (j 4.5 kΩ)

Total magnitude of impedance: 10.21 kΩ (phase angle of impedance vector: 26°)

Bridge

DC resistance: 9.48 kΩ

Inductance: 0.88 H

Impedance: 10.3 kΩ (j 5.5 kΩ)

Total magnitude of impedance: 11.67 kΩ (phase angle of impedance vector: 28°)

Burns 2018 Vintage Tri-Sonic Pickups Characteristics

Neck

DC resistance: 6.48 kΩ

Inductance: 1.58 H

Impedance: 7.76 kΩ (j 9.92 kΩ)

Total magnitude of impedance: 12.6 kΩ (phase angle of impedance vector: 52°)

Mass: 66.2 g +/- 0.3 g

Middle

DC resistance: 6.49 kΩ

Inductance: 1.59 H

Impedance: 7.79 kΩ (j 10.0 kΩ)

Total magnitude of impedance: 12.7 kΩ (phase angle of impedance vector: 52°)

Mass: 65.9 g +/- 0.3 g

Bridge

DC resistance: 7.39 kΩ

Inductance: 2.07 H

Impedance: 9.12 kΩ (j 13.0 kΩ)

Total magnitude of impedance 15.9 kΩ (phase angle of impedance vector: 55°)

Mass: 67.6 g +/- 0.3 g

A fellow Red Special enthusiasts then offered to sell me a set of Brian May specification Adeson Tri-Sonics with the bridge magnet polarity reversed for this project. These are shown in a test fit in the image below. As I indicated in the design phase article, the mounting tabs were slightly too wide to fit in the Strat cavity so I clipped the ends with a pair of snipping pliers.

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Part 3: Pickguard Set

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Part 1: Design phase