mmd8x28
100+ Head-Fier
- Joined
- Oct 30, 2009
- Posts
- 359
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- 10
Hello, been an extremely long time since I last signed on here. But I have done some changes to my audio setup now, and would like an opinion on where to first diagnose one of the problems I'm facing with my Sigma II DAC. This is the original model, not the 24/96 upgraded model.
As far as I know, the 12ax7 tube was never replaced, and this is where I'm thinking I should turn first, but would like confirmation before I take a trip to Sam Ash for a tube, as it's a bit of a drive, but still cheaper than shipping for me (being unemployed and all right now).
Here's the entire setup:
Computer's Digital Toslink Output
Sigma II DAC
Hifiman EF2 Headphone Amplifier
AKG K-240 Headphones
What's happening here with this setup is, when the computer's volume control is set to 100%, on some songs where it gets loud and bassy (like Daft Punks Alive 07, Technologic song, when the song kicks off near the middle), it distorts badly. I have verified that the EF2 is ok as I tried a different DAC, a simple RadioShack one actually (which I use for testing SPDIF outputs usually), no distortion on the same part. This also verifies that the computer isn't having any issues playing the music either, or the source isn't a problem.
It seems the problem is lying squarely on the Sigma II. If I lower the computer's own volume control down to around 80%, this distortion goes away and is no longer audible, but of course, this lowers my SNR too.
What should be my first course of action in troubleshooting this particular issue? I'm almost convinced that the 12ax7 is likely the problem, but would like a second opinion, being I have no access to a tube tester.
As far as I know, the 12ax7 tube was never replaced, and this is where I'm thinking I should turn first, but would like confirmation before I take a trip to Sam Ash for a tube, as it's a bit of a drive, but still cheaper than shipping for me (being unemployed and all right now).
Here's the entire setup:
Computer's Digital Toslink Output
Sigma II DAC
Hifiman EF2 Headphone Amplifier
AKG K-240 Headphones
What's happening here with this setup is, when the computer's volume control is set to 100%, on some songs where it gets loud and bassy (like Daft Punks Alive 07, Technologic song, when the song kicks off near the middle), it distorts badly. I have verified that the EF2 is ok as I tried a different DAC, a simple RadioShack one actually (which I use for testing SPDIF outputs usually), no distortion on the same part. This also verifies that the computer isn't having any issues playing the music either, or the source isn't a problem.
It seems the problem is lying squarely on the Sigma II. If I lower the computer's own volume control down to around 80%, this distortion goes away and is no longer audible, but of course, this lowers my SNR too.
What should be my first course of action in troubleshooting this particular issue? I'm almost convinced that the 12ax7 is likely the problem, but would like a second opinion, being I have no access to a tube tester.
