25-08-2019, 12:27 PM
(25-08-2019, 08:53 AM)Mike Watterson Wrote: It's inexplicable to me.
That's as may be, but it's very real indeed. Huge, in fact. It's not difficult to see how it happens - I'll resist the temptation to use lmgtfy.com.
I'm guessing Mike has an LM317T clone that's been relabelled. In theory a genuine LM317T is good for 1.5A given proper heat sinking and attention to detail, but not all the clones manage the full output current. Of course, it could be something else entirely that works in the same way - there are many possibilities.
Either way, getting higher currents from even a genuine TO220 LM338 can be challenging - a NOS or second-hand LM338 (TO3 package) is a much better bet IME.
A lot of the sellers offering LM338s target the DIY audio market, where they get away with it because the average currents are very low compared to the peak currents (which are handled by the output cap). Their use in audio started many years ago when "Gainclones" were all the rage - some bright spark came up with the (almost entirely pointless) idea of regulating the PSU rails.
