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Electronics => Beginners => Topic started by: Jbliss on July 07, 2015, 09:13:05 am

Title: Amp Power supply Wiring
Post by: Jbliss on July 07, 2015, 09:13:05 am

Hey Guys

Im building a amplifier power supply kit and need some reasurence about the wiring. i have attached a picture of the transformer windings and a picture of the circuit diagram. could some please explain how i connect the transformer up to the rectifier power supply circuit. And explain how I can put the two 40v winding in series as i believe that is required

Title: Re: Amp Power supply Wiring
Post by: Jbliss on July 07, 2015, 09:17:02 am

Heres the Circut

Title: Re: Amp Power supply Wiring
Post by: Jbliss on July 07, 2015, 09:17:34 am

and transformer

Title: Re: Amp Power supply Wiring
Post by: Simon on July 07, 2015, 09:27:57 am

Your two 40V secondaries go in series, you need a 0V and a 40V connected in the middle. To make sure you have them right and if they are not labelled then connect any two together, them measure the voltage on the other 2 if it's 0V they are wrong, if it's 80V they are right.

WARNING 80VAC can kill you, do not touch the probes while measuring.

Title: Re: Amp Power supply Wiring
Post by: Jbliss on July 07, 2015, 09:34:40 am

can i use any of the 0 winding

Title: Re: Amp Power supply Wiring
Post by: dom0 on July 07, 2015, 09:35:25 am

Those are probably intended as pre-amplifier supplies.

A 400 VA toroidal transformer will need some kind of inrush current limiting (e.g. NTC, resistors and timed relays, transformer switching relay). A bigger fuse won't help (much), since a 400 VA toroidal can already trigger your circuit breakers [easily].

Title: Re: Amp Power supply Wiring
Post by: Simon on July 07, 2015, 09:42:45 am

Quote from: Jbliss on July 07, 2015, 09:34:40 am

can i use any of the 0 winding

Well any of the two that are the 40V ones, each secondary is a seperate coil with a wire each end

Title: Re: Amp Power supply Wiring
Post by: Jbliss on July 07, 2015, 09:49:16 am

there is o 0v for the 40v secondaries

Title: Re: Amp Power supply Wiring
Post by: Simon on July 07, 2015, 09:55:05 am

You have 2 wires for 1 40V secondary and 2 for the other. Take one from one secondary and one from the other and see what happens, if you get 0V across the two in series then swap one of the secondary wires.

Title: Re: Amp Power supply Wiring
Post by: LukeW on July 07, 2015, 09:31:42 pm

I'm surprised Silicon Chip is only using 63V caps on those 57V rails. That's not much margin on the capacitor voltage rating - only 10% more, and even less than that if the 240V grid voltage is running a bit high. If you can get caps with a bit of a higher voltage rating that fit the same space and aren't too expensive it would seem prudent to use them.

Title: Re: Amp Power supply Wiring
Post by: Simon on July 08, 2015, 05:46:42 am

Quad amplifiers had this problem and all the smoothing caps failed like clockwork.

Title: Re: Amp Power supply Wiring
Post by: Jbliss on July 08, 2015, 02:18:00 pm

Thanks guys !