[sygyzy]

 
Hi,
 
I have a Headsave META42 and when I plug in any number of headphones (TF10, HA-S500, Brainwavz M4), I can hear a hissing/buzzzing sound, when I have no signal running through it. I am sure the sound is there when I play music but obviously I can't hear it anymore. What causes this? Is there something wrong that I could fix or is it just part of the design?

 

[NA Blur]

What DAC is feeding the Headsave META42?  Is it your PC, an external DAC, or some other device?  To me it sounds like the amp is just picking up a poor signal from a DAC and amplifying the noise as well as the audio signal.
 
In addition the amp itself may be inherently noisy.

 

[sygyzy]

A Super Pro USB DAC 707 DAC is feeding it. It's connected to the PC using a SDPIF (optical) cable. I thought having a DAC outside of the computer would remove noise. Do you think it's a cable issue? I can switch to a different optical cable or I can switch to coax.

 

[NA Blur]

I would try COAX if you can.  You can try each component individually to find the culprit.  First listen to your PC with just the output from a headphone jack on your PC.  Do you hear the noise?  Now add just the amp and feed it the signal from your PC's DAC not the external DAC.  Do you still hear the noise?
 
There may be an impedance issue with the headphones.  Try to use a different headphone particularly one with higher impedance.
 
What audio player are you using?  Try another one and report back if that fixes anything.
 
I still think it is either the DAC ( most likely ) or the amp.

 

[Nagasaki_Kid]

You need to watch what source to use with a headsave meta42. My headsave meta42 doesn't have coupling caps. also more than likely the gain is set for larger fullsize headphones

 

[sygyzy]

Wow, thank you for that. I have no idea what coupling caps are or if my Headsave Meta42 has them. I also don't know what the gain is. Are you saying that if the gain is high and I am using small impedance headphones with them (ie portable cans), that would make them hum/hiss?
 
Re: Coax - I was wrong. My computer doesn't have a coax digital out so I am "stuck" with optical.

 

[Nagasaki_Kid]

well the hissing on mines is very minor when I pair them up my superfi3 which are the most sensitive earphones i own, but absolutely no buzzing. I forgot what gain mines was set at. It's absolutely silent when pair with a 300ohm sennheiser. coupling caps block dc offsets voltage that alot of lineouts have(standard lineout have about 2v). Having no coupling capacitor on the meta42 allows for a cleaner signal when using a source with no dc offset.

 

[sygyzy]

Let me try them with higher impedance cans like my HD600's. Thank you so much for taking the time to respond to my inquiry and for explaining it in an easy to understand manner. I really appreciate it.