On 3/25/2016 11:52 PM, John Heath wrote:
On Friday, March 25, 2016 at 10:23:01 PM UTC-4, Jeff Liebermann wrote:
On Fri, 25 Mar 2016 05:48:15 -0500, "Mark Zacharias"
wrote:

Cautioned him on speaker hook-ups, gave him our hand-out sheet explaining
speaker connections,
which also contains explicit warnings about shorting wires etc.

Put a 0.5 ohm xx watt resistor in series with each speaker. Paint the
resistors with whatever concoction generates the most noxious smoke
possible[1]. Then he shorts the leads again, the resistor(s) will get
hot, smoke, stink, and NOT blow up the output stages. There will be a
loss in output power, which presumably he won't notice unless he's
running low impedance or low efficiency speakers.


[1] Cotton soaked in propylene glycol or white mineral oil which is
what we used for wind tunnel airflow visualization. Propylene glycol
doesn't stink very much, but white mineral oil really reeks.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I have heard this argument too many times as if the costumer is responsible for electrical engineering issues. The customer paid for the amplifier leading a profit for the manufacturer. It is the manufacturer that is responsible to made sure the amplifier is idiot proof. Amplifiers have current limiting circuits which means you can sort the outputs all day long without any damage. If the manufacturer can not be bothered to be responsible for their own engineering leading to output transistor failure than they are in the wrong business. There is no such thing as a costumer that is wrong as he is the one that is paying the money. The failure is always up stream from the costumer. I will now get of my soap box.


I'll have side with the manufacturer here. It is not possible to make
any product 'idiot proof' as someone will come up with a bigger idiot.

By these this standard, car manufacturers should build a car that won't
sustain any damage because the driver is reading the newspaper, texting
or talking on a phone rather than driving. Or from a mechanical side,
not add oil when the light comes on. Not possible, at least not yet.
The end user must also take reasonable care.

Shorting speaker leads is NOT something that the manufacturer can make
idiot proof without significantly increasing cost and/or compromising
performance.

Regards,
Tim