VVR For The AX SEL
Since I was frustrated by the experience of installing VVR on the 18 Watt (not the result but how long it took), I went ahead and timed myself installing the VVR in the SEL – it took only 2H:30M, still longer than it should but much better than spending a whole day!
I also discovered that I did not need to use nylon screws to hold the FET in place, by using plastic washers on both side and plastic insulator, the drain was kept from shorting to the chassis.
The procedure for the installation was the same – 1) put all the VVR components on a small perf board, 2) removed all the un-needed components from the turret board, 3) mounted perf board into the chassis (with FET bolted down), 4) added the new components and wires to complete the installation.
I also took the opportunity to replace the first filter cap in the chain, instead of the original 33uF, I put in a 330uF one, since the SEL used silicon rectifiers, I did not have to worry about exceeding the cold start in-rush current limit for the tube rectifier. Not sure if it really improved the sound or not, but since there was space for it, why not…
With the VVR installed, the amp is now much more usable at low volume as expected, now I can get the power tube distortion by turning up Gain 1 and Gain 2 pots way up, this was not possible without the VVR – it would melt your face off when both pots were cranked! This is a highly recommended upgrade for any mid-high power amp.