A question about transformer wiring

deltaunit · 01:04 PM

Hello,

I'm just starting on my first DIY build, a PSU for my naim preamp and I have a newbie PS transformer question.

I'd like to feed my preamp with 2x 24v rails and the design I am emulating, uses a single transformer with dual centre tapped secondaries.

A cheaper alternative would be for me to get two regular off the shelf transformers and have each one feed one rectifier each before each rail is then smoothed and regulated like above.

I from my limited understanding I think I can wire a 2x ??v transformer (in series?) to emulate a centre tapped V-0-V.

My question then is in order to get a 24v-0-24v output, would I need a 2x 12v transformer or a 2x 24v transformer?

I've looked at this diagram but am confused as to which voltage transformer I need.

Many thanks

sofaspud · 9th June 2011, 02:34 PM

Quote:

My question then is in order to get a 24v-0-24v output, would I need a 2x 12v transformer or a 2x 24v transformer?

The answer to the question is a 2x 24V transformer.
A schematic of your circuit and power requirements of your preamp would be helpful to provide more specific info.

deltaunit · 9th June 2011, 03:22 PM

Thanks Sofaspud. I'm struggling trying to understand transformers so haven't gotten very far yet. Maybe I phrased my question incorrectly as a result. I'm looking for 24v in at each rectifier to give about 34v out going into the regulators (superteddyregs) with a voltage drop back down to around 24v going into the preamp. I'd like to use only half the bridge rectifier (only two diodes) and get full wave rectification like in the diagram.

Afaik the preamp only pulls around 10 or 20ma per rail.

I am a little confused by why joining 2 12v secondaries in series gets you 24v (according to the diagram) but centre tapping doesn't... If that has cleared anything up is it definitely 2x 24v transformers I need?

Cheers,

sofaspud · 9th June 2011, 04:03 PM

Quote:

I am a little confused by why joining 2 12v secondaries in series gets you 24v (according to the diagram) but centre tapping doesn't... If that has cleared anything up is it definitely 2x 24v transformers I need?

Yes, 2x 24V. With dual and center-tapped secondaries, remember where the 0V reference is.

nightanole · 9th June 2011, 04:16 PM

Im confused too. Your preamp needs 24-0-24 regulated?

In that case you get 48v centertap with 4 diodes. Its either that or 2 24v secondaries with each secondary needing 4 diodes.

http://www.williamson-labs.com/image...y-dual-307.gif

deltaunit · 9th June 2011, 04:24 PM

Thanks again Sofaspud

Yes, I probably phrased that wrong, it needs two +24v rails.

9th June 2011, 12:34 PM	#1
deltaunit diyAudio Member Join Date: Jun 2011	A question about transformer wiring Hello, I'm just starting on my first DIY build, a PSU for my naim preamp and I have a newbie PS transformer question. I'd like to feed my preamp with 2x 24v rails and the design I am emulating, uses a single transformer with dual centre tapped secondaries. A cheaper alternative would be for me to get two regular off the shelf transformers and have each one feed one rectifier each before each rail is then smoothed and regulated like above. I from my limited understanding I think I can wire a 2x ??v transformer (in series?) to emulate a centre tapped V-0-V. My question then is in order to get a 24v-0-24v output, would I need a 2x 12v transformer or a 2x 24v transformer? I've looked at this diagram but am confused as to which voltage transformer I need. Many thanks Last edited by deltaunit; 9th June 2011 at 01:04 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Transformer wiring question, series, parallel and center tapped	swin1	Power Supplies	12	7th November 2008 07:58 PM
Quick output transformer wiring question	wicked1	Tubes / Valves	4	30th April 2008 03:56 PM
3886 Transformer wiring stupid question	thermonuclear	Chip Amps	2	16th September 2005 05:38 PM
power supply transformer wiring question	paulspencer	Solid State	8	29th August 2005 03:38 AM
Transformer wiring question	needlz	Chip Amps	6	4th May 2005 05:05 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

9th June 2011, 03:22 PM	#3
deltaunit diyAudio Member Join Date: Jun 2011	Thanks Sofaspud. I'm struggling trying to understand transformers so haven't gotten very far yet. Maybe I phrased my question incorrectly as a result. I'm looking for 24v in at each rectifier to give about 34v out going into the regulators (superteddyregs) with a voltage drop back down to around 24v going into the preamp. I'd like to use only half the bridge rectifier (only two diodes) and get full wave rectification like in the diagram. Afaik the preamp only pulls around 10 or 20ma per rail. I am a little confused by why joining 2 12v secondaries in series gets you 24v (according to the diagram) but centre tapping doesn't... If that has cleared anything up is it definitely 2x 24v transformers I need? Cheers,

9th June 2011, 04:16 PM	#5
nightanole diyAudio Member Join Date: Feb 2009	Im confused too. Your preamp needs 24-0-24 regulated? In that case you get 48v centertap with 4 diodes. Its either that or 2 24v secondaries with each secondary needing 4 diodes. http://www.williamson-labs.com/image...y-dual-307.gif

9th June 2011, 04:24 PM	#6
deltaunit diyAudio Member Join Date: Jun 2011	Thanks again Sofaspud Yes, I probably phrased that wrong, it needs two +24v rails.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)