Headphone Mix hum

[YYR123]

So I have a Hackintosh with a gigabyte board - my onboard audio is disable via - bios/UEFI and I'm just using my Saffire mix control software to be my primary audio device

So I have 5 headphone mixes that have a hum in them like a grounding issue and I have since found out that it is resulted to the buffer size in the playback engine !!! The lower the buffer the louder and more noticeable the hum and conversely the higher the less noticeable

Now that I am writing this post I remember that the GA-X79-UD5 board has a via chipset- I will have to get my TI add in card for FW and try it like that

Anybody have any experiences like that with the buffer settings ? Thanks

[albee1952]

Weird, to say the least. I have always used the onboard audio to feed all non-PT sounds out of my rig. I use a Presonus Central Station and feed the mobo's optical SPDIF to the CS and simply push a button to hear outside of Pro Tools. It might be worth checking to see if your hum changed if you routed ONLY PT to the Saffire. Assuming balanced cables from the Saffire to your headphone amp, you could also try lifting pin #1(xlr) or the sleeve(TRS) at the connectors going into the headphone amp). That would solve a ground loop, IF that was the problem. Is everything plugged into the same AC source? If the headphone amp is screwed to rack rails, have you tried floating it(so the case is not grounded to the rails). Also, if the headphone amp has a grounded AC plug, try an AC "cheater" to see if that affects the hum(if it does, then you do have a ground loop).

[sunburst79]

Interesting. I think swapping cards is a good idea.

Allbee was the one that finally convinced me to use the onboard sound and a cable into the interface. It was better then MME Helper (anyone remember that.

I rarely need more than the two headphone outs on the 003, When I do I use the ADAT optical out to feed a Alesis Ai3 which converts the ADAT into 8 analog outs to feed the headphone amp. I do remember thinking that using an optical connection had the potential to reduce ground noise. Before I had the Ai3 I never had any issues with ground loops when going out analog.

[YYR123]

I will have to look into little bit more - good ideas

[YYR123]

The TI FW card didn't help - think its how I'm running my 3rd party low latency monitoring software and corresponding inputs

I have gotten it to go away for now - by changing the routing

[sunburst79]

Originally Posted by YYR123

The TI FW card didn't help - think its how I'm running my 3rd party low latency monitoring software and corresponding inputs

I have gotten it to go away for now - by changing the routing

Good to know that it wasnt the FW card or chip.

[guitardom]

I would take a ground lift plug and put it on your computer first and test it, then your interface, then your headphone amp. This would at least give you a good idea if their is legit grounding issues.