Need a little help please - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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
Reply
 
Thread Tools Search this Thread
Old 6th January 2013, 02:30 PM   #1
diyAudio Member
 
theodey1's Avatar
 
Join Date: Nov 2010
Default 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. So i thought id just give it a a go. 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
  Reply With Quote
Old 6th January 2013, 02:50 PM   #2
PetruV is offline PetruV  Romania
diyAudio Member
 
Join Date: Dec 2012
Location: Bucuresti
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
  Reply With Quote
Old 6th January 2013, 02:54 PM   #3
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
Quote:
Originally Posted by PetruV View Post
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.
  Reply With Quote
Old 6th January 2013, 03:05 PM   #4
diyAudio Member
 
theodey1's Avatar
 
Join Date: Nov 2010
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
  Reply With Quote
Old 6th January 2013, 03:15 PM   #5
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
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.

Last edited by KatieandDad; 6th January 2013 at 03:20 PM.
  Reply With Quote
Old 6th January 2013, 03:29 PM   #6
diyAudio Member
 
theodey1's Avatar
 
Join Date: Nov 2010
Is there a way to test the current with a multi meter?
  Reply With Quote
Old 6th January 2013, 03:38 PM   #7
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
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.

Last edited by KatieandDad; 6th January 2013 at 03:41 PM.
  Reply With Quote
Old 6th January 2013, 03:46 PM   #8
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
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.
  Reply With Quote
Old 13th March 2013, 09:36 PM   #9
PetruV is offline PetruV  Romania
diyAudio Member
 
Join Date: Dec 2012
Location: Bucuresti
Quote:
Originally Posted by KatieandDad View Post
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
__________________
I know everything but do nothing
  Reply With Quote
Old 13th March 2013, 10:04 PM   #10
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
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.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 13th March 2013 at 10:25 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 02:43 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2