Re-Capping LS5 MKiii Power Supply

[slaikan]

Hi

I'm about to embark on a small project to electrolytic caps the power supply section of an ARC LS5 Mkiii
Can any benefit be achieved in replacing the rectifier diodes with the equivalents or better?

Thanks!

 

[JonSnell Electronic]

In one word, no. (Unless of course they have failed and are either short circuit or open circuit).

 

[slaikan]

Okay, thanks. Pre-Amp seems to working fine, just 28 Years old now, its never had a service.

 

[egellings]

Heat is a major cause of failure for 'lytics, and in a preamp that tends to be low, so caps last a long time in that sort of environment.

 

[Simon1972]

Recapping the lytics can't hurt, likewise replacing those 317 with pin compatible alternatives, lt1085

 

[rayma]

The LT1085 requires 10uF output loading for stability (unlike the LM317), so it's not compatible with this circuit.

 

[grataku]

Has anyone compare the performance of the classic LM317 with the LT series? I don't like LT regs and their stupid tantalum cap requirement for stability. 😉

 

[slaikan]

Not going to attempt changes to the LM317's in this preamp. The heatsinks for the LM317's do run very hot though... measured around 60Deg Celsius

 

[slaikan]

Got KEMET PEH534 for the 470uF, 450v Caps, then Vishay 193 PUR-SI for the 120uF, 450v. Panasonic FR's for the rest. Should be good to go. I normally use Kester 63/37 for all my soldering, but wonder if I should try out some Cardas Quad Eutectic?

 

[egellings]

Not going to attempt changes to the LM317's in this preamp. The heatsinks for the LM317's do run very hot though... measured around 60Deg Celsius

Any chance of using larger heat sinks on those regulators?

 

[slaikan]

Unfortunately there isn't enough physical space for larger heatsinks. One of the heatsinks is right up against one of the caps, and the other sits under a PCB, so limited in height.

 

[egellings]

Shoot! Dag nabbit!