[20nickels]

I run 2 Hafler XL-280's in my main rig. When I power down should I;

1. Give them a signal from my source, hit the power switchs and let them fade out? I have been told this is "draining the caps and is good", but it sounds like horrible little square waves destroying my speakers

2. kill the source and power down in silence.

 

[infinitesymphony]

Better replies below.

 

[yotacowboy]

I've heard this helps prolong the life of tubes, in tube amps... not sure about SS amps, tho.

 

[Uncle Erik]

You will want to discharge the capacitors if you work on your gear. They can still pack a surprise if you go in there shortly after using it.

Discharge usually involves touching them to ground. I don't see how this method would discharge them. Also, I don't think a residual charge harms tubes. I've fiddled with and restored old radios for a good 10 years, and haven't seen residual charges damage tubes.

Your second option works fine; that's what I do.

 

[Ori]

High-voltage stress shortens capacitor life, so it's a good idea to drain these when the equipment is not in use. This is very obvious in vintage tube phase splitters, where the "upper" cap out of a phase splitter sees a higher voltage than the "bottom" cap. Generally you'll find more leaky caps in the "upper" position!
When it comes to power supplies, most designers add a parallel resistor for draining the caps. Not having that is very questionable in my mind. If that Hafler retains charge then the fix is to add a drain resistor, not a "shutdown procedure".

 

[20nickels]

So option #1 is not harmfull to my speakers?

 

[LawnGnome]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif You will want to discharge the capacitors if you work on your gear. They can still pack a surprise if you go in there shortly after using it. Discharge usually involves touching them to ground. I don't see how this method would discharge them. Also, I don't think a residual charge harms tubes. I've fiddled with and restored old radios for a good 10 years, and haven't seen residual charges damage tubes. Your second option works fine; that's what I do.

Touching capacitors to an electrical ground will discharge them as it allows the stored energy to leave.

However, do NOT do this. Hard discharging your capacitors will damage them!

It will also create a nasty spark in high capacitance caps.

The best idea is create a little circuit with some sort of load to discharge the caps more slowly. There is a few examples on the web if you look.