1) First of all a big thank you to Trevor Dymott for allowing me to strip down his amplifier to document it and perhaps increase the amount of information available on the internet.
It's only just arrived so here are some preliminary photographs. The amp is actually in very good condition and much better than the photographs suggest. The control panel has dropped because the two wood screws which locate it vertically are missing. This is very common and easily fixed. All it needs is a check up and some TLC to make it a very desirable amplifier. Trevor has the matching cabinet (minus the hoop stands), the original footswitch and a genuine replacement for the reverb channel selector knob. I suspect he might be open to a serious offer for the outfit once it's serviced.
Although I haven't seen the cabinet, the speakers are silver Celestions and, from pictures of the wiring, I'd say that they were the originals.
2) Power Amp Schematic.
Quick note..... These drawings are only first attempts. Best to refer to the web site rather than copy them until they're finalised.
This is the circuit as found. As I said earlier, this amp is in remarkably good, original condition but, like anything of this age, it's been serviced in the past. There are therefore one or two caveats.
The output transistors are period RCA 2N3055s but they've been changed or refitted at some time.
The drive transistor has been scratched during previous service work and the markings are unclear. It's probably a 2N3054.
The 1K1 resistor in the drive transistor base circuit has been replaced so the value can't be confirmed. The Defiant and Supreme have the equivalent of 1K3 in this position so we're in the right ball park. Incidentally, this is the same resistor that was open circuit in the Supreme on this site and it would be a good place to start if you have a dead power section.
AC and DC voltages are as measured with exactly 240V AC mains. They may be slightly lower than factory quoted figures if these were done at 245V but they'll be normal in the UK today.
The most striking difference between this and the Defiant/Supreme versions is the lack of a second power supply for the drive transistor and pre-amp. These are supplied via a 10ohm resistor from the positive 38V line. The thermal cut-out hasn't appeared yet either.
3) Power Section Wiring.
This is the area of the power amplifier below the chassis.
The only signs of re-work are a couple of new resistors and the extra caps across one of the electrolytics. The original is still in place and could fairly easily have a new capacitor hidden inside it.
Components in the drawings below are shown out of position to clarify the wiring.
The corresponding upper section.
4) Vox Footswitch
The Conqueror shares a common three way effects footswitch with the Defiant and Supreme. Although the casting has a V for Vibrato, all the amplifiers panels are marked Tremolo.
5) Switch On
A quick check of the power section to take voltage measurements showed everything to be working and a healthy 32watts rms output at clipping. The only thing that needs to be done is to re-fit and re-bias the output transistors to cure a DC offset.
Free advice bit.....I know it's interesting to mess with them but the original bias adjusters are wire wound sliders and spares don't exist. They'll be locked with paint and very difficult to free off. So, If the amp's working and doing the job, LEAVE THEM ALONE.
In this case the output transistors had been either swapped around or changed and there was an unacceptable offset and very high quiescent current. There were a couple of mechanical problems too. One 2N3055 only had one screw securing it and both were fitted with unnecessary mica insulating washers. The heatsinks on all of this Vox solid state range are insulated from the chassis and the output transistors should be mounted directly to the metalwork with a thin layer of heatsink compound. It's obviously important to avoid shorting the heatsinks to the chassis or each other when the amp's out of the case.
Setting up the output stage isn't described here as it really requires a fully equiped workbench but, for anyone who takes the job on, aim for about 20mA quiescent and less than +/-20mV offset.
With the output transistors re-mounted and set up, this is a lovely little amp and, while it has any number of effects available, I think most people will find one particular sound that suits their style. Testing it with a 335, I preferred the Brilliant channel with the top boost and reverb on (that's exactly the same set up I used with my old Supreme and a Strat years ago - nothing changes does it).