I'm using a Fiio E17 for both AKG K701s and TripleFi Pros...I think those should be enough. It's a little unnerving as I'm hearing it from an SACD album as well Sucks if it's the recording...
If you're using K701 amped I'll say it's the recording. They're very revealing headphones and make clipping issues very obvious. It's a pretty common issue. Shame that it made it through to an SACD release, if that's the case.