buzzing from speakers

Ryder - It depends what you're touching. If it's grounded case then chances of damage are very low. What if you connect and disconnect something and touch input (or output). Even if you discharge yourself by touching ground or grounded case you might have to go to another room (phone call) and charge yourself back walking on the carpet. I found post on Audiogon where somebody damaged speakers by strong static discharge to TT arm. Again - most likely it will not happen but why to risk your investment. Portable humidifier is a very inexpensive (and healthy) way to prevent the problem.

When somebody tells me that you cannot damage SS gear by static I want to ask this person if he is willing to pay others for damage if he is wrong.

As for the hum - how loud is it? When did you notice? (was it sudden?). Have you changed anything (plug to different outlet, add component etc.)

Pickup from the speaker cable is not very likely. In order to get electromagnetic pickup you'll have to have source (transmitting cable) in order of tens of MHz for 2m speaker cable (2m cable is 1/4 wave antenna at 37.5MHz). Capacitive pickup is possible but you would notice change just moving the cable.

Kijanki, I agree it depends on what we're touching. I was referring to the metal casing and switch at the front panel of the amp when I mentioned it is unlikely the component will be damaged with ESD when touching them with bare hands. I wouldn't risk touching the inputs and outputs of the amp at the back panel with my fingers when the amp is running and risk frying myself. In this case, you are correct that the amp or speakers may be damaged. However, this is more towards plugging and unplugging interconnects when the amp is not on standby mode whereby this static electricity will send a loud pop to the speakers that may damage the tweeter or drivers, or the amp. I hope you are referring to this as I believe components won't get damaged if we touch them(the metal casing or knobs at the front panel) that subsequently cause this ESD to take place.

To minimize or eliminate shock when touching the amps, I am now more prudent by touching some wood before I touch the switch on the amp.

Ryder - "Believe" is the right word. Static might zap the input (or output) if you touch it even if you turn equipment off. Damage to speakers was just an example.

Analog Devices application engineer told me once that they had problems with customer's A/D converters loosing linearity after being zapped by static. To me it is even worst than damage (that can be repaired).

This is one of the most amusing threads I've ever been a part of... If the amp is properly grounded a static discharge from you to the case is going to pose no threat to the amp. You're erroneously imparting a level of concern here to the original poster that's totally unfounded. He's not opening the case and zapping internal components for crying out loud.

You don't need to open case to create static damage. Even with properly grounded equipment it might happen if voltage is high and it is repeated many times. You'll find testimony of that here on Audiogon forum. I am able to destroy prototypes of industrial electronics zapping them few hundred times with 10-20kV zapper to heavy metal case that is grounded directly to copper ground rod (not the flimsy inductive 3th prong). It is not issue of "IF" but rather "WHEN". Situation of repeated static discharge is unacceptable.

It gets much worse if you touch something else than case - like metal knob sitting on the metal shaft of the volume pot and not touching case (small gap). Or even better zap speaker wire (and I assume that grounding is non-inductive and perfect).

If you read more about static damage - one of the first thing advised is humidity control. You'll find many posts of people who damaged their computers by strong discharge to a case.

Stay amused!