[joe_seattle]

Ok...so I went to a local seattle shop to see about possible amps that can breath life into the K340 phones - I heard them properly amped and it was like Sinatra was there giving me a sponge bath.

The guy at the shop seemed VERY wary of hooking up my phones to the speaker outputs of a pre-amp or amp - not because of damage to my headphones, but instead because of possible damage to the amp. Is this true? The K340 have a 400 ohm impedance - they are part dynamic and part electrostatic. My Technics receiver sounds like crap driving them - might this be because its working too hard? Is there a good stereo amp (not designed for headphones) that can power the K340? Thanks!

-Joe

 

[rei_yano]

wow that sounds frightening. didnt know that you could destroy an amp with headphones! lol

 

[Navyblue]

High impedance limits current flow. It is very low impedance aka short circuit that would fry the amp.

 

[Spareribs]

Wow, this is interesting info. So a lower impedance headphone like the Grado SR 60 could damage a home amp potentially? I'll be more cautious. Thanks for the info!

 

[Navyblue]

Most speakers are rated at 4, 6 or 8 ohms, which are lower than the lowest impedance headphones. If an efficient phone like Grado is plugged into a decent powered speaker amp directly on the speaker terminal, the chances of it (I mean the headphone) getting blown is very very good.

 

[Spareribs]

Info like this should be a sticky up in the message board so we can avoid damage. Having a list of "dont's" would be a good way to avoid any potential disasters to our expensive equipment.

 

[joe_seattle]

Ok, all this makes sense. Clearly the speaker outputs have a lot more power which could be turned up high quickly and fry (tear?) A headphone.

Am I roughly correct in thinking of high impedance as...sort of like having a very thin hose through which I am trying to push a lot of water? If I hooked up a thin hose to a water pump, the pump would have to work harder to move the water through relative to a thicker hose? Or maybe it would be like pushing the gas pedal of a car while also holding down the brake?

If an amp is rated at 8 ohms, and my headphones are 400, I'm guessing that means that the amp is delivering very little current overall, because there is such high resistance.

 

[Navyblue]

The water hose analogy is rather apt and often used here.

Yes, the lower the resistance (impedance), the larger will be the current draw. The higher the resistance less current will be drawn. When current draw is too large, it can fry components in an amp.

The highest impedance that the speaker out can "see" is when there is no load connected (open circuit). Impedance of an open circuit is infinity. Not sure about tube amp, but we can't try to blow up a solid state amp by not connecting any speakers to it can we?

 

[G-man]

i doubt headphones can actually damage speaker amps. as it has been said before, the other way around is highly likely. still, i know there are a few electrical guys here, who should provide you with a very accurate, and often interesting answer.

 

[rei_yano]

a sticky would be great! dont break ur crap sticky lol. this has been a good thread. thanks!