headphone amp advice

[snufkin]

hi guys I need some advice on amps

I am building three stand alone headphone amps for a project they need to amplify a fairly low power signal (much lower than guitar more like record or crystal set)

what do I need, a pre and an amp?

are there any projects that could be tweaked for lower level signals to do this?
or will i be fine with a guitar based project ?
I could even go with an off he shelf solution if its cheap

thanks

[Dave_B]

Take a look at this one.  I built it. It's both great and cheap.

[snufkin]

thanks that looks good

any more opinions?

[petemoore]

I am building three stand alone headphone amps for a project they need to amplify a fairly low power signal (much lower than guitar more like record or crystal set)

what do I need, a pre and an amp?
  I guess so certainly, if it's a 'dinky' source signal, for sure.
  When the signal is very very small, as it becomes larger again larger, any 'debris' [noise] may, upon the first amping/''enlarging'', become ''see-able'', further amping may cause the appearance of noticable noise to become very 'un-smooth', ragged, even ugly, and hard to cover up.
  If your input signal is strong enough continuously, the covered up noise may not even be see-able.
  Enough rambling, how well the first pre stages are 'done' and '' '' power supply noise rejection is done might make a difference.
are there any projects that could be tweaked for lower level signals to do this?
or will i be fine with a guitar based project ?
  As far as I'm concerned you'll be fine with whatever you get going, until something about it bothers you, not knowing the source characteristics, hindsight on somethings like these [one-off-proto's] is always much clearer, I laugh at the number of mistaken identities that 'after' has shown, ''40 cannont teach 20 to be 40 until 20=40'', or until you go 2   2   4 with the ____ next door, you never really know what kind of noises you might be hearing.
I could even go with an off he shelf solution if its cheap
  Doug told me something about a Presonus Tube Mic Pre. I have one I took from recording and ''pickup monitor duties'', and put it in the guitar line...drives the reverb/amp...anyway, it's dinky, but has the clean to slight dirt knobs, boosts like...watch you don't over-peg your meters, is a no-noiser [afaict], has the XLR [Balanced] and 1/4'' inputs, and the input/output / knobs, buttons...handy, multi-purpose item. Really makes the recording mics light up, accoustic guitar 'n stuff...whew, now I can back that mic up, worth every penny, performs real nice, every time I try to stump it, it humps out a big wide flat bright clean to cleanish signal [depends on settings/other stuff, it can be made to not distort or distort very slightly/nice].
 

[oldrocker]

The Headbanger is my favorite.  A little tricky when grounding the circuit but other then that it's a great sounding and simple headphone amp.  I made 4 of them and installed them into cigarette cases so they could be used as a 4 way headphone distribution setup for my brothers band.

http://www.minidisc.org/schem.gif