When building my first gainclone I blew (literally) a couple of psu's. The diodes are easy to replace but the caps are harder for me to get living in Mexico.
I'd like to know if they still work so that I can use them for other amps (I have the other parts, including transformers, waiting to buid a pair of active woofers to go with a pair of 3 litre Jordans).
How can I know whether the caps are damaged or not?
BTW: my first gainclone works perfectly now. I didn't kill myself or set the house in fire in the process of building it!
I'd like to know if they still work so that I can use them for other amps (I have the other parts, including transformers, waiting to buid a pair of active woofers to go with a pair of 3 litre Jordans).
How can I know whether the caps are damaged or not?
BTW: my first gainclone works perfectly now. I didn't kill myself or set the house in fire in the process of building it!
I have over 40 years of DIY'ing -- in my youth in the physics lab (even though I was a chem major) , then mostly ham radio equipment, instrumentation, audiophile stuff and programming -- embarrassingly I blew up the caps on several GC's I built by soldering them incorrectly ! Welcome to the club, it proves that we are mortal !
FWIW I use 1000u/63VDC electrolytics bypassed with 10N/100V mylars on the supply rails. All the other bypass caps are 100V. I have used a number of different input caps including 100V EPCOS silver caps, mylar caps from Mouser (B.C. Components) and some exotic General Electric and Corning caps.
FWIW I use 1000u/63VDC electrolytics bypassed with 10N/100V mylars on the supply rails. All the other bypass caps are 100V. I have used a number of different input caps including 100V EPCOS silver caps, mylar caps from Mouser (B.C. Components) and some exotic General Electric and Corning caps.
The caps are probably ok.
It's not always useful to measure capacitance to test for failure. I use three capacitance meters; one on my Fluke DMM, and two stand-alone capacitance meters.
When a capacitor fails it is usually due to leaking electrolyte or evaporation due to age. Measurements of capacitance show a small change, but within tolerance, for the DMM and one of the cap meters. The other meter shows a greater reduction of capacitance for faulty caps. So only one of the three shows a faulty cap as being faulty. The others would show it as being ok.
It depends how they measure it, a leaky cap has a higher impedence (esr etc), which doesn't always show-up in the capacitance reading.
Cyril Bateman designed a meter in Electronics World that would show faulty caps, but it isn't simple, partly because losses are frequency dependant.
It's not always useful to measure capacitance to test for failure. I use three capacitance meters; one on my Fluke DMM, and two stand-alone capacitance meters.
When a capacitor fails it is usually due to leaking electrolyte or evaporation due to age. Measurements of capacitance show a small change, but within tolerance, for the DMM and one of the cap meters. The other meter shows a greater reduction of capacitance for faulty caps. So only one of the three shows a faulty cap as being faulty. The others would show it as being ok.
It depends how they measure it, a leaky cap has a higher impedence (esr etc), which doesn't always show-up in the capacitance reading.
Cyril Bateman designed a meter in Electronics World that would show faulty caps, but it isn't simple, partly because losses are frequency dependant.
By the way, for those interested, part 2 of the above article is:
http://www.siliconchip.com.au/cms/A_101187/article.html
with a couple of interesting links to the author's website at the bottom of the article.
http://www.siliconchip.com.au/cms/A_101187/article.html
with a couple of interesting links to the author's website at the bottom of the article.
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