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Cheap transformer... I think it'd be ok for a LM3886?

Started by Stompin_Tom, August 25, 2006, 05:22:38 PM

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Stompin_Tom

Sorry if someone's already pointed this out, but I just saw it. The current isn't too low/voltage too high, is it?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=129-035

RDV

That's about half what you need to get full power out of an LM3886. It will work, but will be woefully underpowered.

Sorry.

RDV


Stompin_Tom

Ah... I see. Thanks chaps. for some reason I thought it was 25 + 25 volt secondary instead of 12.5 + 12.5. I just didn't look carefully enough. I've been searching around the internet for a deal on a transformer, but I'll probably just go with the toroidal. That can power two chips, where as the cheaper one turbolx5oh pointed out only powers one, correct?

I haven't found anywhere that can compete with part express, yet. Except maybe ebay, but you have to be lucky.

turbolx5oh


Stompin_Tom

mmm... So that extra bit of current would make a difference? I'm no electrical engineer... I've had a hard time wrapping my brain around current vs. voltage. Theoretically, can you run too much current into a chip? I imagine so, but, again, I'm not sure how to think about current.

Maybe I'll look for an article somewhere explaining (in very basic terms) current... Thanks.

turbolx5oh

A transformer is like horsepower in a car.  You can never have too much in my opinion.  The amp will only use what it needs.

RDV

You can over-voltage but it would be hard to over-current.

I'm using a 160VA 22 + 22 volt toroid to power two and it does fine but that's about as low as you can go for two. The 220 VA would give you all the power you'd need.

I've run a single LM3886 on a 18 + 18 volt 56 VA transformer and it was loud as hell!

RDV

turbolx5oh

Quote from: RDV on August 28, 2006, 02:09:27 PM
I'm using a 160VA 22 + 22 volt toroid to power two and it does fine but that's about as low as you can go for two. The 220 VA would give you all the power you'd need.
What size fuse do you have on the mains?