Capacitor voltage in PSU

rkc7 · 21st October 2005, 03:48 AM

I'm thinking about building an amp and looking into sourcing parts for my power supply.

I was going to use the T-amp from 41hz.com, AMP1B, with a 22v toroid for a 30vdc supply. Anyway, I'm looking for some filter caps and I found a few seemingly good deals on Ebay, but I have a problem. Would it be unwise to use 35vdc capacitors for this supply since it is so close to the operating voltage?

Reason is that I found these caps:
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

They look pretty nice and would suit my needs well, except for the voltage rating.

Any opinions on their usage or even quality are welcome!

AndrewT · 21st October 2005, 08:01 AM

Hi,
I don't know the regulation of your transformer but guesstimating at 10% will give an idling voltage of about 34Vdc. To this you need to add the overvoltage allowed from the mains which can be another 6% to 10% above rated incoming AC voltage.

40Vdc caps would be better, however 63V are readily available and relatively cheap.

rkc7 · 21st October 2005, 02:51 PM

I figured 40vdc caps would be the minimum, from what I've read... but I'm not an expert on this matter, so I figured I'd ask.

Apex Jr · 21st October 2005, 03:21 PM

I have a deal on 3 types of caps that might work.
12,000 UF 35V 2 for $1.00
10,000 UF 63V $ 1.50ea
12,000 UF 50V $ 1.29ea
Everyday prices, only problem is I have a $20.00
minimum order...Toroids, RCA Jacks and binding posts
All these are listed on my website www.apexjr.com
Steve

rkc7 · 21st October 2005, 04:31 PM

Thanks Steve, actually I had been looking around your site already and saw those!

21st October 2005, 03:48 AM	#1
rkc7 diyAudio Member Join Date: May 2004 Location: Toledo, OH	Capacitor voltage in PSU I'm thinking about building an amp and looking into sourcing parts for my power supply. I was going to use the T-amp from 41hz.com, AMP1B, with a 22v toroid for a 30vdc supply. Anyway, I'm looking for some filter caps and I found a few seemingly good deals on Ebay, but I have a problem. Would it be unwise to use 35vdc capacitors for this supply since it is so close to the operating voltage? Reason is that I found these caps: http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1 They look pretty nice and would suit my needs well, except for the voltage rating. Any opinions on their usage or even quality are welcome! __________________ Disclaimer: I may be wrong, I may be right. I'd rather believe that I do know what I'm talking about, but am always willing to be told I don't.

21st October 2005, 08:01 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, I don't know the regulation of your transformer but guesstimating at 10% will give an idling voltage of about 34Vdc. To this you need to add the overvoltage allowed from the mains which can be another 6% to 10% above rated incoming AC voltage. 40Vdc caps would be better, however 63V are readily available and relatively cheap. __________________ regards Andrew T.

21st October 2005, 02:51 PM	#3
rkc7 diyAudio Member Join Date: May 2004 Location: Toledo, OH	I figured 40vdc caps would be the minimum, from what I've read... but I'm not an expert on this matter, so I figured I'd ask. __________________ Disclaimer: I may be wrong, I may be right. I'd rather believe that I do know what I'm talking about, but am always willing to be told I don't.

21st October 2005, 03:21 PM	#4
Apex Jr diyAudio Member Join Date: Jun 2002 Location: Torrance, Calif	Cap deals I have a deal on 3 types of caps that might work. 12,000 UF 35V 2 for $1.00 10,000 UF 63V $ 1.50ea 12,000 UF 50V $ 1.29ea Everyday prices, only problem is I have a $20.00 minimum order...Toroids, RCA Jacks and binding posts All these are listed on my website www.apexjr.com Steve

21st October 2005, 04:31 PM	#5
rkc7 diyAudio Member Join Date: May 2004 Location: Toledo, OH	Thanks Steve, actually I had been looking around your site already and saw those! __________________ Disclaimer: I may be wrong, I may be right. I'd rather believe that I do know what I'm talking about, but am always willing to be told I don't.


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