Salvaged caps - what to keep?

[Structo]

Just to keep everybody on the same page, you are measuring DC voltage usually in millivolts, correct?

mV not mA

You can calculate the current through the 1M resistor though.

[overtone]

thanks for the catch, i have just edited that mA to mV.
I am a bit fuzzy right now, testing different Trapist beers on an Island off Holland.
A 6G4a is on my to do list. Good choice. Sweetspot = coupling caps.

[martin manning]

Measure in volts and call it microamps, or measure in millivolts and call it nanoamps ;^)

[Meat&Beer]

...testing different Trapist beers on an Island off Holland.

Trappistes Rochefort 10 is the best Trap beer ever! Woah.

Ahem.. I mean, capacitors.

[overtone]

haa agreed, Rochefort have not had a drop of that in ages.

[ampfab]

speaking of testing coupling cap leakage, I found this in an old electronics magazine this weekend. I built one, seems to work. I went through my vintage caps, found some with slight leakage. I also tested it's sensitivity using resistors, definitely will find leakage over 20 meg ohms.

[ampfab]

a few more docs

[mrn1ngstr]

I just completely gutted a Dukane 1U460 and every single cap except one mica domino on the tone stack was bad. I was really hopeful about the non electros but no love. The ones that didn't test open were at least 50% over or more. It had a bunch of C&D tiny chiefs and after a close inspection of a couple, they had cracked along the seems lengthwise AND in the middle.

[eniam rognab]

thanks ampfab!!

im buildin it

[morcey2]

Phil, not related to the question at hand, but the 6SJ7's control grid needs a ground reference.

Matt

[Phil_S]

Phil, not related to the question at hand, but the 6SJ7's control grid needs a ground reference.
Matt

Thanks for the mention of this. I think that is a really good catch! I should add a grid leak to ground. Gibson used a 10M on the GA20. I'll add that after I resolve the power tube problem. Right now, the 4 position switch is pulled as is the tube.