Sounds great, but you need a steady hand
The first thing that struck me when I opened up the back of my VT999, and looked at the circuit board was "I'm gonna need a finer tip on my soldering iron and a magnifying glass". All of the points that you will be soldering things to are very small and very close together, so a fine tipped soldering iron and fine gauge solder, and probably a magnifying device are in order (and a steady hand helps). The modification itself is very straight forward, simply a matter of adding a switch, and soldering the components and wires into the right places, the whole process only took 20 minutes.
How does is sound? I upgraded the tube while I had thing thing open (Sovtek 12AX7WA) and plugged it into the effects loop circuit of my Fender Princeton 112, and was very pleasantly surprised. Gone is the awkward on/off crunch of the stock setup and in it's place is much smoother, controllable overdrive sound. It really brought some life to this solid state amp, and I'm looking forward to trying it with my tube amp.
The only concerns I have are about durability as the solder points to the circuit board are tiny, but that has more to do with my janky soldering skills.
Verified purchase: YesCondition: New