Old DIYtube ST-35 electrolytics - swap?

bloozestringer · 24th October 2011, 03:46 AM

I got a Rev.B board last year that had been populated in 2003 I believe. Never been powered up, and I've had it sitting for nearly a year as I can't decide if I want to build it or go to a SS power amp with a tube pre. Anyway, what's your opinion of powering this board up as far as the electrolytics are concerned? Swap them out at this point? FWIW, I don't have a variac so that's not an option.

Eli Duttman · 24th October 2011, 04:11 AM

Light bulb trick?

bloozestringer · 24th October 2011, 04:44 AM

Quote:

Originally Posted by Eli Duttman

Light bulb trick?

To be quite honest I haven't even bothered to buy the iron for the board yet

I was just weighing my options if I need to replace 8 big caps or just forget it.

Rod Coleman · 24th October 2011, 07:30 AM

9 or 10 years since manufacture is certainly marginal for good sound.

If they are decent quality, you can still use them, with the Panasonic method of restoration:

Use a high-power series resistor to limit the leakage current (start with 47K 14W, say). Apply 200 to 400Vdc for a minute, and watch the voltage across the resistor drop. If the leakage current you measure falls to the rated value, they should be safe.

Panasonic, Nichicon are good enough quality to give this a try. Caps with odd names, and Illinois (IC) TTA series etc are often poor, and not worth even a small amount of trouble.

24th October 2011, 03:46 AM	#1
bloozestringer diyAudio Member Join Date: May 2005	Old DIYtube ST-35 electrolytics - swap? I got a Rev.B board last year that had been populated in 2003 I believe. Never been powered up, and I've had it sitting for nearly a year as I can't decide if I want to build it or go to a SS power amp with a tube pre. Anyway, what's your opinion of powering this board up as far as the electrolytics are concerned? Swap them out at this point? FWIW, I don't have a variac so that's not an option.

24th October 2011, 04:11 AM	#2
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	Light bulb trick? __________________ Eli D.

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24th October 2011, 07:30 AM	#4
Rod Coleman работник diyAudio Member Join Date: Jul 2004 Location: Warwickshire UK	9 or 10 years since manufacture is certainly marginal for good sound. If they are decent quality, you can still use them, with the Panasonic method of restoration: Use a high-power series resistor to limit the leakage current (start with 47K 14W, say). Apply 200 to 400Vdc for a minute, and watch the voltage across the resistor drop. If the leakage current you measure falls to the rated value, they should be safe. Panasonic, Nichicon are good enough quality to give this a try. Caps with odd names, and Illinois (IC) TTA series etc are often poor, and not worth even a small amount of trouble.

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