Power Supply Question - Page 2

Captn Dave · 22nd September 2008, 05:15 PM

Dave, that's some solid advice and it had occured to me but the point is to get my feet wet with tube circuitry and I'm in no hurry to listen. I have a nice el34 Jolida going right now and sound is not a problem. I'm just out to futz around with this pig. I might fit it with a rectifier tube later on because I'd like to see if I can hear the difference so often attributed to the rectifier tube.

Mr. Navarro. That comment went right over my head, but I will research your ideas. Just not that familliar with ss power suppy circuits yet. Thanks for your input.

jackinnj · 22nd September 2008, 06:02 PM

capacitance multiplier

http://sound.westhost.com/project15.htm

Captn Dave · 3rd October 2008, 04:30 PM

I believe I will part out that Knight amp and use the tubes and output transformers on a future project and use the power transformer to make an adjustable B+ power supply for experimentation.

I've got all the pieces together and I'm ready to build the regulated power supply using the LR8 regulator and TIP50 transistor. (the schematic is posted in the thread a few post higher; post 8). I'll mount a pot so I can control the voltage.

But I do have a question. The drawing calls for using 20 and 40uf caps as filters. I have some 220uf 400V snap in caps that I would like to use. What are the pros and cons of using more capacitance that is needed in a filter role?

koolatron · 3rd October 2008, 06:28 PM

Significantly increasing the power supply capacitance can lead to inrush current problems as the caps are energized. Series inrush limiters are available; I don't suggest simply replacing the fuse (you have installed a fuse, right?) with a higher-current one.

-k

Captn Dave · 3rd October 2008, 07:20 PM

Ok, that is the explaination I was looking for; the con of excessive capacitance.

I have other smaller caps that I can use and will do so. I was thinking this might be an opportunity to use these larger caps.

Also, one frequently sees large caps at bargain pricing and it's always tempting to by them instead of their pricier smaller counterparts.

Thanks for your comment, And yes, I have a fuse.

3rd October 2008, 04:30 PM	#13
Captn Dave diyAudio Member Join Date: Jun 2008	Filter cap values I believe I will part out that Knight amp and use the tubes and output transformers on a future project and use the power transformer to make an adjustable B+ power supply for experimentation. I've got all the pieces together and I'm ready to build the regulated power supply using the LR8 regulator and TIP50 transistor. (the schematic is posted in the thread a few post higher; post 8). I'll mount a pot so I can control the voltage. But I do have a question. The drawing calls for using 20 and 40uf caps as filters. I have some 220uf 400V snap in caps that I would like to use. What are the pros and cons of using more capacitance that is needed in a filter role?

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22nd September 2008, 05:15 PM	#11
Captn Dave diyAudio Member Join Date: Jun 2008	Dave, that's some solid advice and it had occured to me but the point is to get my feet wet with tube circuitry and I'm in no hurry to listen. I have a nice el34 Jolida going right now and sound is not a problem. I'm just out to futz around with this pig. I might fit it with a rectifier tube later on because I'd like to see if I can hear the difference so often attributed to the rectifier tube. Mr. Navarro. That comment went right over my head, but I will research your ideas. Just not that familliar with ss power suppy circuits yet. Thanks for your input.

22nd September 2008, 06:02 PM	#12
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	capacitance multiplier http://sound.westhost.com/project15.htm

3rd October 2008, 06:28 PM	#14
koolatron diyAudio Member Join Date: Jul 2006	Significantly increasing the power supply capacitance can lead to inrush current problems as the caps are energized. Series inrush limiters are available; I don't suggest simply replacing the fuse (you have installed a fuse, right?) with a higher-current one. -k

3rd October 2008, 07:20 PM	#15
Captn Dave diyAudio Member Join Date: Jun 2008	Ok, that is the explaination I was looking for; the con of excessive capacitance. I have other smaller caps that I can use and will do so. I was thinking this might be an opportunity to use these larger caps. Also, one frequently sees large caps at bargain pricing and it's always tempting to by them instead of their pricier smaller counterparts. Thanks for your comment, And yes, I have a fuse.