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theodey1 6th January 2013 02:30 PM

Need a little help please
 
Hello, I've been lurking about for a few months on this great site trying to learn all i can, but am now a little lost in all the info.:confused: So i thought id just give it a a go:eek:. Bought these

http://i1305.photobucket.com/albums/...ps6a898bdb.jpg


http://i1305.photobucket.com/albums/...ps6a898bdb.jpg

http://i1305.photobucket.com/albums/...ps6a898bdb.jpg

on ebay for a good price and found an old av amp. Would the transformer be ok for the amp? and how do you wire it up in the simplest way for stereo use. Thanks for Helping

Ryan

PetruV 6th January 2013 02:50 PM

Just use the two greens and the black for an amp.The others arent split or are too low voltage to be used,just ignore the,leave them unhooked with some insulators on the end ,the transformer mut probably be able to output is full power on any of its windings,for example if the transformer is 100w it will be able to output 100w on any of the voltages but not more than one at a time

KatieandDad 6th January 2013 02:54 PM

Quote:

Originally Posted by PetruV (Post 3313434)
Just use the two greens and the black for an amp.The others arent split or are too low voltage to be used,just ignore the,leave them unhooked with some insulators on the end ,the transformer mut probably be able to output is full power on any of its windings,for example if the transformer is 100w it will be able to output 100w on any of the voltages but not more than one at a time


ABSOLUTE B**LL***S.

100VA Transformer will be built to supply 100VA over its secondary windings. If it has two secondaries both rated at 50VA then the MAXIMUM power that can be supplied by each secondary is 50VA.

You MIGHT get away with marginally more than that but the redundant winding doesn't magically supply it's current to the winding that you are using.

theodey1 6th January 2013 03:05 PM

This is the problem ive been having reading all these post, lots of people are very helpful giving answers etc but a lots of different opinions:p

KatieandDad 6th January 2013 03:15 PM

Problem is that none of the photos show the current rating of each winding, without that information no-one can help.

30-0-30 and 14-0-14

It is likely that the 30-0-30 is the high current winding and the 14-0-14 would be for a pre-amp type supply but we can't be sure.

Even if it were, in an AV amplifier the low voltage supplies could be quite heavilly loaded.

theodey1 6th January 2013 03:29 PM

Is there a way to test the current with a multi meter?

KatieandDad 6th January 2013 03:38 PM

NO.

If you had the working AV amplifier you might have been able to measure the currents at full power but statically you can't.

Unfortunately you have bought a lemon. To be on the safe side buy a known transformer with its known specifications.

KatieandDad 6th January 2013 03:46 PM

If you knew what you were doing you could approximate the running AV amplifier.

It is possible to use regulation voltages to assume the full load current of each winding.

If I have lost you I won't say any more because you need to know what you are doing to achieve this.

PetruV 13th March 2013 09:36 PM

Quote:

Originally Posted by KatieandDad (Post 3313440)
ABSOLUTE B**LL***S.

100VA Transformer will be built to supply 100VA over its secondary windings. If it has two secondaries both rated at 50VA then the MAXIMUM power that can be supplied by each secondary is 50VA.

You MIGHT get away with marginally more than that but the redundant winding doesn't magically supply it's current to the winding that you are using.

Saiyng that for transformers which dont have a wattage rating on the secondaries,of course the ones with wattage rated secondaries ca only output max their rating

sreten 13th March 2013 10:04 PM

Hi,

Whilst one statement in this thread is "ABSOLUTE BALLCOCKS",
its very unlikely the transformer is a lemon. Use the 30-0-30V
for the chip amps, and 14-0-14V for any op-amp based preamp.

Measuring each windings DC resistance will give you a good idea
of current capability. E.g. using the same wire a 14 V tap would
be around half a 30V tap, but I would expect it to be higher as
I expect it to use thinner wire for that tap. Same with the other
taps, any decent tranny design DC resistance is a good indicator.

rgds, sreten.


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