Author Topic: First post and A212 capacitor question  (Read 2870 times)

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Offline theduster

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First post and A212 capacitor question
« on: January 24, 2010, 03:15:20 pm »
A recently bought an A212 locally with the intention of making it my project for the next month or two.  The amp is in great cosmetic condition, but has a few issues that I think can be cured with a little TLC.  A few google searches led me to this site which I have been reading over the last few days.  First things first, a few pictures.





As you can see I took the chassis out first thing to have a look under the hood. 

I suspected the amp was in need of a recap and my suspicions were confirmed when I had a look around.  Several of the electrolytic caps had leaked and made a mess.  I found a wiring diagram for the A212 and have been using it to work through the circuit checking resistor values etc.  The diagram calls for a 80/80 MFD 500 V cap.  I have checked tubesandmore.com and can't seem to find an appropriate replacement (can or otherwise).  I'm also aware that there can be issues with the caps seeing more voltage then they are designed for due to wall voltages being higher now then they were when the amp was designed.  I was looking for some advise on an appropriate replacement for this capacitor.

Thanks in advance for any help.

Offline biltmore

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Re: First post and A212 capacitor question
« Reply #1 on: January 24, 2010, 08:33:23 pm »
Welcome to the Sunn forums! That's one hell of a fine amp you have there. I have one myself, and I absolutely adore it.

Hopefully Edbass, Isaac, loudthud, or mckinnon audio will be able to help you out. There's definitely some knowledgeable people around here. Just give it a bit of time.
« Last Edit: January 25, 2010, 02:24:30 pm by biltmore »

Offline mckinnon audio

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Re: First post and A212 capacitor question
« Reply #2 on: January 25, 2010, 03:25:16 pm »
   Hi there,you can try this,it will work.Replace each 80 mfd @ 500 VDC side of your dual cap with (2)-200mfd @350 VDC caps joined in series with a 220k 1 watt resistor paralleling each cap.This ends up giving you 100 mfd @700 VDC,I know it's a little more than the orig. 80 mfd.,it'll just give you a little more "staying power".The resistors share the power surge,making it easier on the first cap in line.Hope this helps,good luck,Mel.