I found a second hand Wide Body Mesa Boogie Mark IV combo housing and ordered a corresponding
Aluminum Chassis Mesa Width Style and got some special delivered chassis straps for it and put the DIY Ampmaker NX5 inside
combined with a B-Stock 12 inch 16Ohm Celestion G12H anniversary speaker
for now running with a Mesa 12AX7 and a JJ EL844 ?
One of its greatest features, is the Power pot, a VCB/VVR voltage control kit going from 256 Volts at maximum to 21 Volts at minimum (actual measurements), making overdriving the tubes by diming (not dimming) both Gain and Master pots a breeze, for tasty rock sounds in the living room. The diy build manual says:
“First amplification stage
This is the first stage of the amplifier and it uses one half of the preamp valve to amplify the low level guitar signal. The final part of this section of the circuit includes the Gain pot, which controls how much of this boosted signal is fed into the second stage.
Second amplification stage
The guitar signal – still fairly clean so far – is fed into the second part of the amp. If the Gain control is set high, the incoming signal will overdrive this second amplification stage to create some preamp distortion. The output of this stage then runs through a network of resistors, capacitors and pots that allow you to control the treble, middle and bass frequencies of the signal that will be passed along to the power valve. With the EQ Bypass switch enabled, however, you can choose to have the full output of this stage passed along to the power valve.
Power stage
The power stage, which includes the Master volume control, the power valve and the output transformer. The Master volume is the simplest part – a pot that lets you dial in how much signal the power valve receives. Low settings for cleaner tones, and at higher settings you can overdrive this valve to get maximum distortion.
High-voltage supply
In the N5X, there’s a Variable Voltage Regulator (VCB) circuit. You can use the VCB pot to dial down the voltage supplied to the power stage. There’s just one good reason to do this: it lets you have power-valve distortion at any room volume, from 0W and 5W.”
It will pair up with my Marshall DSL-5CR
This was a fun and educational (9 months!) build !
Read More “N5X British Overdrive amplifier part 2”
