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Old 29th September 2004, 12:38 PM   #1
poeee is offline poeee  Australia
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Default Transformers (extreme n00b ahead - proceed with caution!)

I'm thinking of doing something like the BrianGT kit and have a question about transformers.

Being on quite a low budget, I was wondering what kind of things I can rip transformers out of instead of buying them new. Stuff like microwaves and stuff. Is it rather safe for a n00b to be doing this, or should I just buy new ones?
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Old 29th September 2004, 03:24 PM   #2
Nuuk is offline Nuuk  United Kingdom
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Quote:
Is it rather safe for a n00b to be doing this, or should I just buy new ones?
I think you already to know the answer to that one! Transformers are not that expensive!
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Old 29th September 2004, 03:25 PM   #3
ofb is offline ofb
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um, "is it safe"? it's lethal voltage. you better do some studying so you know what you're doing.

if you mean will it work to use recycled transformers, then that's more of a "depends". you might want to look at transformers that are already made for audio equipment, like in discarded 70's receiver amps like technics, kenwood, yamaha.

the problem there is they tend to be center tapped, not dual secondary, and their voltage tends to be a little on the high side for gainclone use. but look around, you might have some closet queen that would be good to convert into a gainclone.

and i wouldn't touch a ******* microwave. don't they use a high voltage circuit? there'd be positively dangerous charge sitting in the capacitors, just like in a monitor. there are some things you don't mess with untill you're very experienced.

http://www.gallawa.com/microtech/safety.html
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Old 29th September 2004, 03:51 PM   #4
Duo is offline Duo  Canada
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Uhuh, definitely no microwave oven transformers are going to be good for a gainclone. They are over 1000V and current limited, certainly not what you're looking for. Also, it's quite dangerous to muck around with one of these cantankerous subjects.

The best would be to look, as others have specified, in old receivers and the like, which have transformers rated for something within the confines of normal audio use.

They are mostly center tapped for use in split power supplies, but sometimes you'll get lucky and find something that will work in there. Just be careful and observant. A multimeter is your friend in telling what the transformer does.
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Old 29th September 2004, 04:49 PM   #5
tg3 is offline tg3  United States
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Default Re: Transformers (extreme n00b ahead - proceed with caution!)

Quote:
Originally posted by poeee

Being on quite a low budget, I was wondering what kind of things I can rip transformers out of instead of buying them new. Stuff like microwaves and stuff.
I fear we will soon have a recipient of a Darwin Award.
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Old 29th September 2004, 05:50 PM   #6
dvdwmth is offline dvdwmth  Canada
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you sure you dont have an electronics surplus shop where you live? Maybe good deals there.
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Old 29th September 2004, 06:52 PM   #7
Sherman is offline Sherman  United States
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Default Re: Transformers (extreme n00b ahead - proceed with caution!)

Quote:
Originally posted by poeee
I'm thinking of doing something like the BrianGT kit and have a question about transformers.

Being on quite a low budget, I was wondering what kind of things I can rip transformers out of instead of buying them new. Stuff like microwaves and stuff. Is it rather safe for a n00b to be doing this, or should I just buy new ones?

Don't get too hung up on transformers. Get a new one but there is no need to spend a ton. I've now built several GC's including one from BrianGT's kit and have used a variety of transformers.

You can get perfectly good sound and power from a 48VCT 3 amp transformer driving both channels. I have exactly that setup running right now.

Something like this- http://www.partsexpress.com/pe/showd...number=120-225

(part number 120-225 in case the link doesn't work). I actually got a pair with similar specs at a local surplus store for $9.50 each.

Later on if you decide you need more power or happen into some additional cash you can install a different transformer.
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Old 29th September 2004, 07:19 PM   #8
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Default Re: Transformers (extreme n00b ahead - proceed with caution!)

Quote:
Originally posted by poeee
I'm thinking of doing something like the BrianGT kit and have a question about transformers.

Being on quite a low budget, I was wondering what kind of things I can rip transformers out of instead of buying them new. Stuff like microwaves and stuff. Is it rather safe for a n00b to be doing this, or should I just buy new ones?

18V-0-18V 300VA Toroidal Transformer

That's the transformer that I'm using. 2 of them for my 6 channel GC amp. Jaycar can mail order, or there may be a shop near you. If AUD 70 is too much for you, you might be able to scrape by with the 160VA version at AUD 48.

Steve
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Old 29th September 2004, 08:36 PM   #9
sam9 is offline sam9  United States
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Alas, transformers are the component that would be most desiriable to "scrounge" but the most difficult to find in an apropriate configuration.
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Old 29th September 2004, 09:25 PM   #10
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I use toriods from Harbuch.

http://ourworld.compuserve.com/homep...ch/harbuch.htm

They are usually cheaper than Jaycar and made locally. They have an very large selection, every VA and voltage you could want.

The one Jaycar toriod I bought buzzes. I was probably just unlucky though, as I haven't read other people complaining about them.

BTW: I don't know what the postage costs are.
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