Electrical:
Mechanical:
SST-AC15-OT Details:
SST-AC15-OT is our fully layer wound recreation of the original output transformer used in Vox AC15 amplifiers produced between 1961 to 1964. It is an extremely faithful turn-for-turn, layer-for-layer reproduction of the original, including the the low permeability core material and use of dielectric wax as an impregnation compound.
Starting sometime in 1961 the output transformer design issued by Vox for the AC15 saw a shift as new suppliers started producing it. Where Haddon had previously used mostly glassine paper for layer insulation, slightly thicker kraft paper became the new standard amongst the new vendors. The cumulative effect of this change was a reduction in lumped winding capacitance along with a change in the dissipation factor between primary and secondary sections. Sonically, this change contributed to a higher self-resonant frequency and a more open top end response giving us more of that signature chime from the EL84 output section. Less upper midband resonance compared to the Haddon produced transformer.
Our SST-AC15-OT output transformer replicates all of these unique attributes to bring back exactly what makes this design such a hallmark of early 60’s British guitar amplifiers.
Currently we produce the following variants of SST-AC15-OT:
- [SST-AC15-OT] - Base design as described above. Laydown mounting with original solder terminal layout. Vacuum impregnation with our custom dielectric wax formula
- [SST-AC15-OTH] - Haddon specific recreation with glassine paper insulation. Laydown mounting with original solder terminal layout. Wax impregnation. Lower SRF with more upper midband resonsance than SST-AC15-OT. See -OTH data sheet for specific information.
- [SST-AC15-OTV] - Base design as described above but PVC leads instead of solder terminals. Vertical “upright” mounting with bell end hardware. Utilizes our standard VPI finishing process which allows for a more agressive top end response.
See -OTV data sheet for specific information.