Qucik'n'dirty headphone amp

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Hello.
I'm going away for a few days (www.dreamhack.org), and i'm only bringing my laptop, which can hardly drive a pair of "ear shells" (those tiny things that you put in the inside of the ear), so i need a headphone amp that i can put together in an hour or two on an experiment board.

What i need is:
*Single voltage feed (only + voltage avavible).
*No opamps.
*A fairly standard transistor/transistors. A non-transistor dependant design would be best.
*Reasonably high input impedance
*Reasonably good sound quality.

Anyone know of a suitable design?
 
paulb said:
1. What impedance are your headphones?
2. What are you powering it from?
3. Why no opamps? What about small power amp chips?

Anyway, check out the DoZ headphone amp, project 70 at www.sound.au.com
1. 574ohm DC reistance. that'd be around 600ohm, right? It's sennheiser HD410 in case anyone got any nymbers for it.
2. Don't know yet.
3. I can't get my hands on a decent opamp in just one day (less then 20 hours now).

Yea, alreadly looked into the DoZ, but i can't get my hands on all that stuff in 20 hours i'm afraid.
 
Hi,
I´m about to build this one next:
Zen headphone amplifier
This should have more than adequate sound.
Meets all your needs but is class a and can´t be built in 1-2 hours. And the input impedance won´t be that high either.
Actually with your time schedule I´d indeed build something with an opamp. Why not?? The "Cmoy" (Headwize) would be perfect for breadboard.

There are much more really nice sounding headphone amplifiers on Headwize .

Jens
 
Christian said:
Hi,
I'm also thinking of building an headphone amp amp, and that circuit ( http://space.tin.it/scienza/fladelle/Page31.htm ) is nearly perfect!!! Only one thing though; I only got BC337 and BC227 transistor, so could i replace the BC239C with a 337 instead?

Best Regards,
/Chris
Yes, BC337 is a fast trasistor(100Mhz), only different is that it can take some more power(= more current). you mean BC327, I think
 
joensd said:
Hi,
I´m about to build this one next:
Zen headphone amplifier
This should have more than adequate sound.
Meets all your needs but is class a and can´t be built in 1-2 hours. And the input impedance won´t be that high either.
Actually with your time schedule I´d indeed build something with an opamp. Why not?? The "Cmoy" (Headwize) would be perfect for breadboard.

There are much more really nice sounding headphone amplifiers on Headwize .

Jens

I'm not anti-opamp, the problem is i can't get my hands on a decent opamp before tonight. A friend drew a quck scetch of an amp at school that i will probably go with, since i have the needed components at home.
 
No cap is needed???

paulb said:
It looks like they forgot the cap. Should be one in series with the phones.

I am not sure there is going to be any cap.
Gain is set for up to 300 ohms, R3/R1 = 6.8
And 1.5 V over 300 ohms is
is only 7.5mW.

The only danger is when you put very low quality
16 ohms HP in. Gives 140mW at DC.

But then you almost certain can change the
R3 to 10 kohm for gain=1
This gives a DC voltage at outputbelow 1.0 volt
Like 56mW over the phone.

To publish a "dangerous" construction on the web,
and not be corrected if,
seems to me unlikely.

This design has been around for several years.

If you have very low impedance HP, 16/32 ohms, of course you
can use a good Output cap.

For 100 ohm and and higher, the max power
will be below 25 mW.
If the circuit is built so it puts out 1.5 Volt DC.
 
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