Quick Question: Using headphone on speaker amp

[a shovel]

Basically it is a 120 ohm K501. I am not going to cut the plug off and put the four wires in the respective posts, but this time I will be wiring a jack.

I heard about problems using a three conductor jack that shares the ground on the amp. It burns out the amp or something? I remember a solution with resistors between the posts or something, but cannot find it anymore. Anyone care to comment? It is supposed to be like this

AMP . . . . .1/4jack
L- ----------L --->
G- - \
-------G ---> headphones
G- - /
R-----------R --->



But I know theres something missing before the amp binding posts and the jack. Resistors across the ground or something... A picture with the explanation would be nice..

Thanks guys.

[amb]

It depends on the amp. For amps that have passive output ground, there is no problem sharing the ground. But active ground or bridged amps cannot be used in this manner. You could verify this with a DMM. With the amp powered off, measure the resistance between the left and right output ground terminals. If you read near 0 ohms, then it's ok to share.

The main problem with using a speaker amp to drive headphones is that it most likely have too much gain, and therefore will be noisy (typical headphones are much more efficient than speakers, what's inaudible through speakers would be unbearable through headphones). Also, the high output may fry your headphones. The usual solution is to insert series resistors to reduce the output (as well as the effective gain), but that is also less than optimal.

[safronlove]

Very simple you will have heavy noise i think try for another circuit..or need to add one more capacitor

[JadeEast]

http://sound.westhost.com/project100.htm
Here is one way to do it.

[a shovel]

Thanks for the replies Ill measure more when I get home. I remember getting a relatively large dose ~63mv of dc on each channel lol, but after listening for hours nothing seemed wrong. (Headphone burn in anyone? )

I'm about to just get a 41hz kit to play with.. see how that works out for hphones..