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-   -   2nd P/S Replacement for LM317 (https://www.diyaudio.com/forums/power-supplies/360106-2nd-replacement-lm317.html)

tribute 13th September 2020 06:05 AM

2nd P/S Replacement for LM317
 
Hi, The reason for my previous Jung P/S question was that the LM317 side of my current P/S using LM317/LM337 blew. So I thought if I need to spend money on it should I take the opportunity to upgrade, as the background noise using my current P/S is higher than I would like. Using 2x12 VDC batteries the P/amp is very quiet, but they are a PITA to charge.
However the Junk is apparently not suitable (or so I have read) with my AD797 op-amp in my phono amp.
HOWEVER DOING SOME FURTHER RESEARCH!!
I have found these on Bbay!!!!

Linear Technology LT1963 + LT3015 upgrade LM79XX negative voltage regulator | eBay

I need between +/-9 to +/-15VDC to run the P/amp

Cheers & thanks for your patience

Rick PA Stadel 14th September 2020 07:13 AM

Have you checked into member Elvee's "De-Noizator" project? That would likely solve your noise problem.

What do we know about what killed the last LM317?

What is providing the input power to the regulators? How much voltage headroom do you have? The LT1963 is limited to 20V.

The LT1963/3015 link you gave looks pretty expensive for what it is -- and likely not enough of an *upgrade* for the price. Nice that it would 'plug right in', though.

Cheers

knauf1919 14th September 2020 08:10 AM

Quote:

Originally Posted by tribute (https://www.diyaudio.com/forums/power-supplies/360106-2nd-replacement-lm317-post6339621.html#post6339621)
I have found these on Bbay!!!!


Another Chinese joke. Try Denoiser or Salas' regulator.
Salas SSLV1.3 UltraBiB shunt regulator
D-Noizator: a magic active noise canceller to retrofit & upgrade any 317-based V.Reg.

PRR 14th September 2020 09:43 PM

Quote:

Originally Posted by tribute (https://www.diyaudio.com/forums/power-supplies/360106-2nd-replacement-lm317-post6339621.html#post6339621)
....the LM317 side of my current P/S using LM317/LM337 blew....

:eek: How did that happen?? :confused:

Johno 14th September 2020 10:22 PM

Hi Tribute, jump on the Linear Tech website and check out their 3 pin regs. Some are leaded but most are surface mount alas. However the high performance regs are very low noise and very fast compared to 317/337 technology. From memory there are LT versions that are drop in replacements. Believe samples can be ordered from LT direct (at cost).

The LT1963/3015 pair are much better than 317/337 and quite fast. By fast I mean they will supply current loads at frequencies beyond audio while still maintaining accurate voltage regulation.

tribute 15th September 2020 02:24 AM

Hi Guy's thanks for the replies.
The unit is a Omishra power supply +12/-12 VDC, I bought with phono amp from a member of Lenco Heaven.
It worked for a day & then the + voltage dropped out to 0. Contacted the member put not reply, so I guessed I would have to try to repair myself. So I thought why not try to upgrade it. And no I do not know why it blew, so I will initially try another LM317, as they are quite cheap before trying any upgrade.

I did lot of browsing, but most of it went over my head as does both the Salas options & the LM317 de-nosier.

So yes I am weary about the China options, that's why I asked about any other upgrade drop in units

Cheers

PRR 15th September 2020 10:16 PM

> then the + voltage dropped out to 0.

Why blame the '317? It's not fragile, and is self-protecting against most faults. I would check all solder joints and connectors first.

And if it is not the '317, then all this angst for "drop-in" is moot.

egellings 15th September 2020 11:05 PM

I would want to know what caused the LM317 to fail in the first place. One reason they do is if you place a large cap on the output of the Vreg and a smaller one on the input. When you power down, the input voltage drops quickly due to the smaller input cap, and the output cap then discharges through the Vreg, killing it. To prevent that, put a 1N400x cap from input to output of the Vreg such that the diode is reverse-biased when the Vreg is operating. The diode will conduct discharge current around the Vreg upon power-down, protecting it. If there is a large cap on the reference pin of the Verg to gnd, remove the cap. You just don't need it. Something like 0.1uF is fine for that location--nothing more. Do the same for the LM337 as well, observing the reversed polarity.

tribute 16th September 2020 05:57 AM

Now unit working
 
Hi Guy's, The unit is now working, I borrowed a small 3 wire trans from a friend (no I do not normally have that so laying around, as i try to only work with DC)

So What was wrong, I have no idea, but again this unit was bought from a well respected contributor on another site. When I 1st received it from Germany it worked playing music for a day, so i know in his configuration it did definitely work.

The way he had powered the board was with a 12VDC SPMS, With the + wire going to the center connector & the of the voltage 3 way input block & the - wire was going to what would be the positive line.

There is a possibility the the original European SMPS was wired back to front, but I do not think so as it was one of those units that plug straight into the wall. I cannot check because I do not like going through conversion plugs & so I have already dumped it.

So ow yes we are back to the original question. What is the best straight swap three-terminal voltage regulator for the LM317/337. Is there a better & hopefully cheaper choice than the one I originally posted.

Thanks for your time

Cheers

Vovk Z 16th September 2020 06:38 AM

Quote:

Originally Posted by tribute (https://www.diyaudio.com/forums/power-supplies/360106-2nd-replacement-lm317-post6342960.html#post6342960)
So ow yes we are back to the original question. What is the best straight swap three-terminal voltage regulator for the LM317/337. Is there a better & hopefully cheaper choice than the one I originally posted.

There isn't any better IC with pin-to-pin compatibility. But it depends on what you state as 'better', because there are more powerful ones (LM338, LM350 etc) and there are low drop ones (LM1086-LM1083 - those ones are noisier).
But there are other IC which can be done in 'three pin LM317 format' and there are additional circuits (were posted here) - Denoiser or De-noisator etc.


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