I just got a 36 w on trade and it seems odd that I have to dime the master and roll up the volume to get it to drive.
...Is this just normal for this amp? I was told by the owner that it is Nik built.
The basic "18 watt" circuit from which this amp is derived gets a lot of it's overdrive from the PI/poweramp setup. Actually, it's what makes the amp hard to tame for cleans.
So, having to turn up the Master to get more drive wouldn't be surprising; that said, I don't know enough bout your to say if it's the "normal" level of drive or not.
Isn't it normal to turn the volume up and keep the master low to get the amp to overdrive?
Turning down the Master does NOT increase drive. The master is there to let you decrease volume while retaining any existing preamp clipping.
The "18/36 watt" is NOT a high-gain amp with a lots of preamp gain and clipping. Much like the old Plexi and metal-panel JPM's, it relies on a combination of preamp and poweramp overdrive to get those "classic rock" tones. If you were to plug into a real 50-wat JMP, you might be surprise at how loud it gets before it ever starts to breakup.