Headphone out for Ruby amp?

[siaoguitar]

hI, BUILDING THIS  RUBY MINI AMP:

http://www.runoffgroove.com/ruby.html
was wondering whether i can add a 1/8" headphone out to the circuit before the speaker & after the 220f cap? and can i turn the speaker off by inserting my headphone?

[B Tremblay]

Yes, you can add a headphone output to Ruby.  You'll need a 1/8" closed circuit stereo jack.

[Mark Hammer]

It may well be a smart idea to put some attenuation in there.  Half a watt into a speaker sitting on a table in front of you is one thing.  The same half  watt into a pair of headphones will have you responding to your lover's discrete suggestions with a hand cupped over your ear and yelling "What!?  WHAT??  You want what?" by the time you're 30.

Since you'll likely want to use stereo headphones, and they will likely consist of a pair of 8-ohm drivers, that represents a 4-ohm load when both earpieces are placed in parallel.  Again, not good for your hearing. and likely to make the volume control too twitchy for those trying to save their hearing.

I'd suggest sticking a 1/4W  15-ohm resistor in series with each ear.  Assuming 8-ohm drivers, that'll give you an effective load of (2*23)/2 = 23 ohms, which will bring down the volume levels nicely.  If it's too low, then try 12R or maybe 10R resistors.  Some headphones use 32-ohm drivers and these may be fine.  Alternatively, if the headphones are inefficient, you may have no problems/risks.

[siaoguitar]

Hi Mark, nice explanation there, but how exactly should i connect the 1/8" jack? just before the speaker?
will inserting my earphones cut the sound to the speaker?

And : can i make the signal to the earphones stereo, since the earphones is 2 sides(left,right) ?

Can u like draw it out for me please?

Thank You
GOD BLess!!