Transformer from Sony A/V Receiver - what's up with these windings?

Stephen Morgan · 3rd February 2007, 05:53 PM

A friend gave me a transformer from a Sony A/V receiver. He didn't know the Sony model, I think it was 7 channels, or maybe 7.1, possibly 100 Watts per channel. I figure if Sony was claiming 7 channels of 100 Watts, it might be a good start for a 2 channel 100 Watt amplifier. Output devices are MP1620 / MN2488.

The secondary high current winding has 5 wires, with voltage as follows, measured with 120 VAC on primary, no load on secondary:

Orange - 44
Yellow - 27.4
Black - 0
Blue - 27.4
Red - 44

So, we have the makings of a +/- 62 VDC or +/- 38 VDC supply. According to my math, that would be about 240 Watts or 90 Watts into 8 ohms.

Anybody know how this thing was used? Guesses also welcomed.

XEAGLEKEEPER · 3rd February 2007, 09:58 PM

Sounds about right. If there is a part number you could call sonys techline and maybe find out the VA rating?

zeonrider · 3rd February 2007, 10:20 PM

Measured dimension of that transformator.
Maybe we can calculate VA rate(transform in mm ).
Regards zeoN_Rider

XEAGLEKEEPER · 3rd February 2007, 10:34 PM

Have you tried googling that part number?

Stephen Morgan · 3rd February 2007, 11:19 PM

Actually, what I was wondering about was the voltages - one pair seems too low for a 100 Watt amplifier, the other pair seems way too high.

I was hoping maybe someone had seen one of these before and knew what Sony did with those taps.

XEAGLEKEEPER · 3rd February 2007, 11:26 PM

Have a look at these amps
http://sound.westhost.com/project3a.htm 100watt 38vdc
http://sound.westhost.com/project101.htm 180-200 watt 66vdc

Stephen Morgan · 5th February 2007, 04:59 AM

Thanks for the amplifier recommendations XEagleKeeper, but allow me to drag this back on-topic:

Why are there two sets of taps on the secondary?

XEAGLEKEEPER · 5th February 2007, 10:21 PM

Probably because the sony required two different supply voltages.Real hard to say without a schematic!Possibly lower voltage for the preamp,flatamps and higher voltage for the poweramps???

Stephen Morgan · 6th February 2007, 04:33 AM

Hmmm. +/- 38 VDC is a bit high for a preamp, and I have no idea what a flatamp is (neither does Google

). And this is the high current winding - there is a separate low current winding measuring 14-0-14 that is almost certainly for the low-level stuff.

Thanks.

djk · 6th February 2007, 07:28 AM

Voltages sound right for a 5-ch 100W class H amplifier.

3rd February 2007, 09:58 PM	#2
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	Sounds about right. If there is a part number you could call sonys techline and maybe find out the VA rating? __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*

3rd February 2007, 10:20 PM	#3
zeonrider diyAudio Member Join Date: Mar 2004 Location: Belgrade RS	Hi ! Measured dimension of that transformator. Maybe we can calculate VA rate(transform in mm ). Regards zeoN_Rider

3rd February 2007, 10:34 PM	#4
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	Have you tried googling that part number? __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*

3rd February 2007, 11:26 PM	#6
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	Have a look at these amps http://sound.westhost.com/project3a.htm 100watt 38vdc http://sound.westhost.com/project101.htm 180-200 watt 66vdc __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*

5th February 2007, 10:21 PM	#8
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	Probably because the sony required two different supply voltages.Real hard to say without a schematic!Possibly lower voltage for the preamp,flatamps and higher voltage for the poweramps??? __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*


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3rd February 2007, 11:19 PM	#5
Stephen Morgan diyAudio Member Join Date: Dec 2004 Location: Tennessee	Actually, what I was wondering about was the voltages - one pair seems too low for a 100 Watt amplifier, the other pair seems way too high. I was hoping maybe someone had seen one of these before and knew what Sony did with those taps.

5th February 2007, 04:59 AM	#7
Stephen Morgan diyAudio Member Join Date: Dec 2004 Location: Tennessee	Thanks for the amplifier recommendations XEagleKeeper, but allow me to drag this back on-topic: Why are there two sets of taps on the secondary?

6th February 2007, 04:33 AM	#9
Stephen Morgan diyAudio Member Join Date: Dec 2004 Location: Tennessee	Hmmm. +/- 38 VDC is a bit high for a preamp, and I have no idea what a flatamp is (neither does Google ). And this is the high current winding - there is a separate low current winding measuring 14-0-14 that is almost certainly for the low-level stuff. Thanks.

6th February 2007, 07:28 AM	#10
djk diyAudio Member Join Date: Feb 2001 Location: USA	Voltages sound right for a 5-ch 100W class H amplifier. __________________ Candidates for the Darwin Award should not read this author.

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