• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

USB powered DAC -> Battery powered headphone amp -> headphones - ground issue

michalrz

michalrz

Supreme [H]ardness
Joined
Jun 4, 2012
Messages
4,877
Hello audiophiles,

I'm preparing a gift for a friend. He recently got himself a pair of some nice sennheiser headphones.
I would like to give him my USB DAC. It draws power from USB. As it does not do any amplification beyond the PCM2704 DAC, I am planning on connecting Left,Right and Ground from its 3,5" jack output to a CMOy headphone amplifier I've once built. It needs symmetrical power and as such it has a virtual ground formed by two resistors.
The CMOy I used to power using a 12V lead-acid UPS battery or a 12V lead-acid cash register backup battery.
And here's the problem: I am quite certain I'd run into issues by having two grounds: one from USB on DAC stage and one from the battery in the amplification stage. Will there be DC offset issues? The connection is unbalanced after all. I'm afraid I'll damage his headphones or something in between.
Could anyone help me with this particular configuration?
Maybe I should use his PSUs MOLEX to power the CMOY amp instead of using a gel battery and thus 'equalize' the potentials between those two devices?
 
You must log in or register to reply here.
Back
Top