KA3x7 vs LM3x7; is there a difference & bargain price

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smiler

smiler

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Joined 2008
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Hi all,

In searching for replacement regulators for my Cyrus amp, I came across a Farnell bargain!

They have a few hundred non-RoHS compliant KA317 and KA337 Fairchild regulators in stock, which they're flogging at a lower price to get rid of the old stock. This seems like a great deal, and I'm certainly not bothered about RoHS compliance for my amp.

In case you're interested:
Fairchild Semiconductor KA337 19p/ea @ Farnell
Fairchild Semiconductor KA317 21p/ea @ Farnell

However, I just want to check that the KA chips are really equivalent to the LM series. Comparing the datasheets side-by-side, the figures look identical. I just wanted to check before I get tripped up by this. The amp has LM317 and LM337 chips at the moment.

Thanks :)
 
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smiler

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mjf said:
i think the difference is small (compared to lm..........) but - as always - big enough to beginn a high end discussion......
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Haha, I hadn't actually expected a discussion like this, but I guess this is the place! My primary concern was any practical reason that the KAs wouldn't work.

Okay, now we've established that they'll work: what differences do you think there are mjf? Does anyone have some measured results to support an acoustic difference?

On a side note, I found a comment on Head-Fi (via Google) that the Fairchild chips were found to be less reliable than National Semiconductor in a particular project. Should I be concerned about this? I'm not entirely sure how they were being used (as CCS I suspect).
 
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dangus

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Joined 2004
Aren't there some regulators from Linear Technology which perform BETTER than the National Semiconductor originals? I don't know if they'd make an audible difference, but it's more likely to be audible than, say, making connections with "silver wire w/natural unbleached cotton tubing" to quote something funny I just read elsewhere.
 
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smiler

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Joined 2008
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dangus said:
Aren't there some regulators from Linear Technology which perform BETTER than the National Semiconductor originals? I don't know if they'd make an audible difference, but it's more likely to be audible than, say, making connections with "silver wire w/natural unbleached cotton tubing" to quote something funny I just read elsewhere.
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Never underestimate the power of cotton tubing ;)

How does Fairchild fair then? Is the performance difference accountable to some measured difference (perhaps evident in the data sheets?). For my purposes, I'm satisfied that the KA317/377 is up to the job, especially at only 20p each! I'm interested this discussion though...
 
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