[sdiy] Headphone amps using op-amps

[dragons]

Hi,
well having a resistor in series with the opamp output will certainly 
help with preventing damage in case of shorts, and also if you are using 
a stereo jack and someone plugs in a mono jack which shorts out one of 
the outputs !
I guess there is quite a lot of variation in resistance of headphones, 
so working out the series resistor may be a bit of trial and error.
off the top of my head 8v p-p does seem a bit too much.
regards Peter B

On 12/12/12 18:36, Veronica Merryfield wrote:
>
> On 2012-12-12, at 9:52 AM, Tom Wiltshire<tom at electricdruid.net>  wrote:
>
>> If I'm driving a pair of cheap headphones from a standard op-amp (I've got a TL072, a MC1458 or a LF353 available -

  you don't get much more 'bog standard' than that lot) is there 
anything special I need to do?
>
> I use NJM4556AD - it can provide 70mA to the output. I try to rig it as a follower stage only although one can use some gain, in which case I add some roll off.

  I add a resistor in series with the load just to protect it from 
shorts etc. Working fine in 1000s of units out there.