Hey Guys,
I was just about to solder in the 820pf and 390pf ceramic caps I got today to replace the SilverMica ones (they were just way too big...)
Now I'm hesitant though...the 820pf measured as 696pf and the 390pf as 366pf.
Now, with the tolerance of my DMM (+/- 5%+5) it could actually be that they're off even more.
Should I hold off, and buy some new ones, or just try it ?
Of course, just knowing they're off will make me believe something is not right when I play with it.... :-\
You could put a 100pf and 47pf resp. in parallel with each to get them closer. Personally, I never check cap tolerances....I don't think my DMM even has the capability.
Out of curiosity, where did you buy the mica caps that were too big?
Quote from: madbean on August 05, 2010, 11:30:06 PM
You could put a 100pf and 47pf resp. in parallel with each to get them closer. Personally, I never check cap tolerances....I don't think my DMM even has the capability.
That´s a very good idea. Thanks Brian
Quote from: Haberdasher on August 05, 2010, 11:35:56 PM
Out of curiosity, where did you buy the mica caps that were too big?
I got them from www.banzaimusic.com (Berlin, Germany)
Normally they´re just fine (I´ve just them on lots of pedals) and Banzai has them a little bit smaller as well, but on a tight board like this, there is just not enough room.
If you´re in Europe, you should check them out, they have a large slection of parts. Of course they ship worldwide, but I think the EURO vs USD would make them quite expensive for you guys in the US.
I bought and built a capacitance tester last spring. I judiciously test every cap and resistor, once when I assemble my bits, and right before I solder them in.
I do this to justify sending $10.00 to Hong Kong for a tester kit. I have kept myself from putting the completely wrong cap in the wrong place, but I have never detected a difference in tolerances. Generally, 10% is acceptable, and many electros don't even get THAT close.
Quote from: CRBMoA on August 06, 2010, 09:59:23 PM
I bought and built a capacitance tester last spring. I judiciously test every cap and resistor, once when I assemble my bits, and right before I solder them in.
I do this to justify sending $10.00 to Hong Kong for a tester kit. I have kept myself from putting the completely wrong cap in the wrong place, but I have never detected a difference in tolerances. Generally, 10% is acceptable, and many electros don't even get THAT close.
Yeah, that's why I found it a little bit weird. In 3 years, I never had a part (resistor, cap, or anything) that measured significantly different than the mentioned value....
You what's even weirder ?
I paired these caps with some other ceramics to get close to the specified value. Gt it up to 820 (should be 820) en 390 (spot on). soldered the caos together, and before soldering them to the board, measured them once again........980pf, and 460pf...WTF ?
Took of the extra caps again, and measured the original ones...800, and 380. Close enough to the specified value; but completely different from what they measured before.....