Power Supply Transformer

bal704 · 7th November 2006, 12:08 AM

I'm getting ready to start on the LM4780 kit from AudioSector.

http://www.audiosector.com/lm4780.shtml

I happen to run across a pair of 24V transformers, but they only have single secondaries. Is there any way to get it these to work for this circuit, or do I need dual secondaries?

Sherman · 7th November 2006, 01:48 AM

Quote:

Originally posted by bal704
I'm getting ready to start on the LM4780 kit from AudioSector.

http://www.audiosector.com/lm4780.shtml

I happen to run across a pair of 24V transformers, but they only have single secondaries. Is there any way to get it these to work for this circuit, or do I need dual secondaries?

You can use two transformers that have single secondaries. Just use one trafos secondaries for the AC1 H&N and the other secondaries for the AC2 H&N.

CarlosT · 7th November 2006, 03:13 AM

Bal where did you see the single secondary transformers? Were they toroids?

bal704 · 7th November 2006, 12:13 PM

I bought them locally. They are Mercury Magnetics 24V transformers. I've attached a pic.

Also, if I have to use 2 of them, can I connect both xfmrs to the same AC plug, or will each xfmr need it's own?

I_Forgot · 7th November 2006, 03:01 PM

You can use one line cord to power both transformers. You should also install a fuse. Be careful about getting the line cord "polarity" correct.

The nature of your question leads me to believe you have never wired anything like this before. I recommend that you find someone local to you who has some experience with this sort of thing and have them check your work before you connect power to it.

Test your power supply before you go to the trouble of building and connecting the amplifier circuit.

Good luck!

I_F

bal704 · 7th November 2006, 03:52 PM

Thanks for the help. This is my first PS project, and I intend to build and test it before I hook it up to my amp.

Thanks again

CarlosT · 7th November 2006, 05:27 PM

What do you do if the tranny has dual 115V primaries? I just wanna run 115V coming in...

CarlosT · 7th November 2006, 05:29 PM

BTW I just found a super deal on Avel Lindberg encapsulated toroidals...90VA 20V+20V 7% regulation for $20 each. Would this make a decent transformer for a single LM3875?

bal704 · 7th November 2006, 05:31 PM

Where did you find that deal? Send a link.

CarlosT · 7th November 2006, 05:34 PM

No link...email me if you're interested cdtres@mindspring.com

7th November 2006, 12:08 AM	#1
bal704 diyAudio Member Join Date: Oct 2006	Power Supply Transformer I'm getting ready to start on the LM4780 kit from AudioSector. http://www.audiosector.com/lm4780.shtml I happen to run across a pair of 24V transformers, but they only have single secondaries. Is there any way to get it these to work for this circuit, or do I need dual secondaries?

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7th November 2006, 03:13 AM	#3
CarlosT diyAudio Member Join Date: Oct 2006	Bal where did you see the single secondary transformers? Were they toroids?

7th November 2006, 03:01 PM	#5
I_Forgot diyAudio Member Join Date: Jan 2005 Location: Phoenix, Az.	You can use one line cord to power both transformers. You should also install a fuse. Be careful about getting the line cord "polarity" correct. The nature of your question leads me to believe you have never wired anything like this before. I recommend that you find someone local to you who has some experience with this sort of thing and have them check your work before you connect power to it. Test your power supply before you go to the trouble of building and connecting the amplifier circuit. Good luck! I_F

7th November 2006, 03:52 PM	#6
bal704 diyAudio Member Join Date: Oct 2006	Thanks for the help. This is my first PS project, and I intend to build and test it before I hook it up to my amp. Thanks again

7th November 2006, 05:27 PM	#7
CarlosT diyAudio Member Join Date: Oct 2006	What do you do if the tranny has dual 115V primaries? I just wanna run 115V coming in...

7th November 2006, 05:29 PM	#8
CarlosT diyAudio Member Join Date: Oct 2006	BTW I just found a super deal on Avel Lindberg encapsulated toroidals...90VA 20V+20V 7% regulation for $20 each. Would this make a decent transformer for a single LM3875?

7th November 2006, 05:31 PM	#9
bal704 diyAudio Member Join Date: Oct 2006	Where did you find that deal? Send a link.

7th November 2006, 05:34 PM	#10
CarlosT diyAudio Member Join Date: Oct 2006	No link...email me if you're interested cdtres@mindspring.com