I modified my Neumann VMS70 again. I've always disliked how the heat can be applied to the stylus when the vacuum isn't on. It opens up the possibility of baking bits of chip to your stylus. No amount of solvent will clean off carbonized chip. When you bake chip to your stylus, your grooves will not be as clean as they were before carbonizing chip to your stylus. It will show up as background hiss on playback.
This forces the operator to turn the heat potentiometer down to zero when changing out the stylus or when auditioning audio through the head without the vacuum running (so you can monitor the substitutional feedback network and watch your amps on your rack). I like to see how audio will ping on my meters. So, I will drop the head outside the platter with the heat off. But, sometimes, I forget to turn the heat off. Or, sometimes I forget to turn the heat back on and start cutting test grooves. That is also bad for your cutting edges.
Finally, I dislike moving the old potentiometer that much. Turning it down and then adjusting it back up takes it's toll and is honestly a frustratingly dumb design. Even Al said as much. I think I have him on video talking about how it was silly to not have had that switch with the vacuum. I digress, eventually the heat potentiometer will wear out and need replacing. Now, I never have to mess with that knob again. My mod disconnects the heating wire when the vacuum is not running.
I am going to have these boards fabricated and housed properly. If anyone is interested in installing this mod I can supply it fully fabricated and ready to be easily installed. I can even send you a 304 cable to use while you send yours to me for modding. The only thing tricky part is installing the switch wire. I can assist with that remotely. It really isn't that difficult. Please contact me via my site http://www.deepgroovesmastering.com for price and availability.
Here is the Schematic. Video below.
Here is the video.