Finally Started my build

[rlyach]

My Crack came over a week ago and I finally got a chance to start working on it. I built the base first. I decided to use the wood that came with the kit and add a rosewood inlay. I used Danish Oil (walnut) for color and finished with BriWax. I polished it with a car polisher. Now on to the plate modification to accommodate a hum-dinger virtual center tap. I will use a 220 ohm multi turn wire wound 2W POT.

 

[mcandmar]

A hum what now?    Nice work on the base!

 

[rlyach]

A virtual center tap to reduce heater hum. Here is an excerpt from the article on Valve Wizzard

 

[Paul Birkeland]

I'd recommend trying that in the circuit before adding holes.  If it ends up being inaudible, its presence may detract from an otherwise lovely build.

 

[rlyach]

Good point! I have used this technique successfully on guitar amps I have designed and built. It is amazing how well it works. I had some POTs left over so I thought I would put one here. It will be behind the transformer so it shouldn't get in the way. There is a knob included in with the POT so it will look pretty good. Just an extra knob behind the transformer. I will give it a listen. I plan on building it without the speedball first.

 

[rlyach]

Paul,

The only reason I wanted to put the hum pot in was because of the comment in the manual that an alternate ground point for the heater winding was recommended for lower heater noise. This comment, plus my experience with guitar amps caused me to think I should put a virtual center tap in the circuit. Also, I have seen from several posts that some do have some hum. I figured that even if it was superfluous, adding the POT wouldn't hurt. I assumed that others who have had noise were rare and probably had extenuating circumstances, but since the pot fits so well, I figured why not.

 

[rlyach]

I decided to paint the top plate and transformer bell. I also painted the transformer laminations with high temp paint. I used scotch brite to smooth out the lacquer, cleaned with denatured alcohol and applied a hammer coat paint. Now on to the actual build.

 

[jboehle]

Looking good!