Power supply upgrades

Elizabeth, have you heard equipment with power supply upgrades? I only ask because I have heard of folks who did power supply upgrades and claim to have heard positive changes. I suspect this to be truthful as some manufacturers and modders offer upgrades to power supplies that contain premium parts.

At one time an outboard (separate chassis) set of additional electrolytic capacitors was a popular mod. Easy to do. It was helpful if the amp's power supply was undersized.

I'm not familiar with the Nichicon electrolytics, but assuming they are of at least decent quality I don't think you'll gain anything by replacing them. You might realize some small benefits by paralleling ("bypassing") them with good quality film caps, of lower value, although I agree with Elizabeth that capacitors in the signal path are much more critical.

Electrolytics provide filtering of ac ripple, and energy storage. They almost invariably provide poor performance at high frequencies, so bypassing them with a polypropylene or other good film capacitor will potentially help filter out noise or other garbage before it reaches the components that are in the signal path (where power supply decoupling/bypass capacitors are presumably incorporated as well, but cleaning up the dc voltages as much as possible before they enter those areas can't hurt and might help).

The capacitance values you listed for the electrolytics strike me as adequate for the relatively low and fairly constant current draw of a 3 x 12AX7 phono stage, so I don't think there is anything to be gained by increasing their values. Adding the film bypass capacitors will, of course, provide a bit of added capacitance as an incidental benefit.

Regards,
-- Al