[Yoda]

I have a Castanet that I use as a linestage.  One issue I've had, especially w/ high watt power amps is that there was a low level 120hz hum.  After checking my build and discussions w/ Jim, he recommended moving the first choke on the power supply away from the output transformers because of some possible magnetic coupling.    I added some leads to test the theory and viola - noise floor dropped.  I also tried the other choke, but that had no effect so it stayed in place.  So I mounted the choke on the back of my castanet, and things went from great to even better!  I imagine that separating the entire power supply into a remote box would be the next level, but I'm happy with this setup.
Matt

PS - anyone have any tricks to pull one of those tiny pins in the selector switches?  I need to move one over one notch.  So far it has resisted shaking, magnets and general persistence.

[Watson]

Which potentiometer are you using? Is that the stock one?

[Yoda]

Its a PEC pot, not standard, per recommendation of another builder.  Found it on digikey.  Other non-standard features:
Hovland 3.3uF caps, Russian teflon bypass caps (.10 or .22uF?), input selection for 4 inputs, switched monitor out (line out) for recording, RCA line out tapped on HI output.  I modified the front and rear panel files and they were CNC'd by Front Panel Express. Oh yeah - and leather washers on the 'outboard' choke..

[flocchini]

Yoda

Nice mod. When I'm home I'll try this.

If you try a 6H6P please post. I'm interested in your comments. The 6H6P draws slightly less current than the 6H30. Through my headphones the sound seems more smooth or liquid which I know is a personal assessment.

Best

Bob

[tubesforever]

Thanks for all the notes.  I am intrigued about using the Castinet as a line stage.  That super tube is simply begging for attention. 

Off boarding power supplies seems to be the best way to eliminate EMI.  Did you try wrapping the main transformer with TI shield? 

Thanks again for posting!

[Yoda]

tubes - buried in the 08 hagtech blog is some info on the ls-10 which is like a capacitor coupled version of the castanet.