Help with Zen Headphone Amp - hiss...

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Built Marcello's headphone amp last evening. Sounds great except for a faint hiss (sounds like white noise).

Details:

Measures about 5mVPP at the output terminals when connected to paused source (a Sony DVD player) measuring 0mVPP.

Sony 75 Ohm headphones.

Don't have it in an enclosure yet - part's on the truck. Did connect ckt ground to line ground via 100 Ohm resistor.

Noise disappears when I short the input terminals of the amp boards.

Amplitude is constant regardless of bias settings or source level.

Used a few cheap (RS) carbon comp resistors in non-power situations (I live in a small town).

FETs matched to 300uV.

Thanks in advance for any assistance,

Bryan A. Thompson
batee@roadslessphotographed.com
 
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