Naim HiCap2 - one output too high

[Pete MB&D]

If your reg really is dead (which I would say is the least likely of all the components in the circuit), you could use one of the eye-wateringly expensive LM350Ks that RS sell I reckon.

Texas Instruments LM350K STEEL/NOPB , 1 Linear Voltage, Voltage Regulator 3A, 1.2 → 33 V 3-Pin, TO-3 | RS

uk.rs-online.com

I've had my hi-cap fail on me twice (it actually uses TO220 LM317s) and both times it's been a tant.

It never ceases to amuse me that Naim's crazy-expensive (and surprisingly effective) pre-amp PSU uses one of the cheapest and nastiest ancient Vregs!

Lifted straight from the data sheet.

Pete

 

[colasblue]

And actually the simplest and lowest performing variation of the circuit on the original datasheet!

Mind you in the mid 70's when the Naim regulator design came out the 317K wasn't the cheap thing it became- it was actually state of the art and quite expensive.

 

[MJS]

If your reg really is dead (which I would say is the least likely of all the components in the circuit), you could use one of the eye-wateringly expensive LM350Ks that RS sell I reckon.
<snip>

I've had my hi-cap fail on me twice (it actually uses TO220 LM317s) and both times it's been a tant.

It never ceases to amuse me that Naim's crazy-expensive (and surprisingly effective) pre-amp PSU uses one of the cheapest and nastiest ancient Vregs!

As someone who has had literally thousands of these regulators in my hands over the years I stand by my earlier statement that this particular failure mode is the regulator. The tants go leaky and pull the output or the adjust pin down, and thus reduce the output voltage.
Martin's acoustica pages have a great section on how to get the best out of these regulators. For a DIY approach - if you can find a couple of supercap regulator boards from someone's upgrade they can be converted into tracking pre-regulators, and two will fit vertically into the space vacated by the horizontal Hicap board with a bit of jiggery pokery.

Personally I'd drop a replacement quiet power supply board in. Get in touch with @The_JJ

 

[The_JJ]

As others have said bad tants will pull the output down, changing them is an easy first step, but the circuit works without them, it's just much noisier. I would often snip them and check the output voltages once more. The resistors are usually fine.
The regulator feedback is trying to make 1.2v between Ref and OP, if it's not that, especially with the tants removed its the 317.
I have a box of good salvaged ones and plenty of PCBs if you need them