My musical tastes are similar to the OP's and I have owned both these headphones. My HD650s were recabled with a SAA Equinox cable. I have also owned the HD600.
While I think there are better options out there at higher prices for...
Like you, I enjoy all things classical, and I have owned a number of different headphones. If you have a strong preference for detail and neutrality in a sound signature, then I would recomend that you consider buying a used Stax system....
I have owned them both and sold them both. The answer to your question is "it depends". If you prefer a very smoooth sound signature that is on the warm side of neutral, with bass emphasis and laid back ... It has to be the HD650. If...
I would highly recommend the Shure SRH1840s. IMO listening to an opera like Strauss' Der Rosenkavalier, for example, eliminates a lot of headphones because of their treble quality, but the 1840s handle this music with ease, and are very...
I would also recommend that you take a look at the Sennheiser HD-600, which has a very smooth, non-fatiguing, laid back, and quite neutral sound signature, IMO.
The AKG-701/702 mentioned has a very neutral but what I...
Version 1 with no returns/issues since purchasing them new in 2010. 'A' version of the grills and angled connectors. 9/10 condition - no marks, scratches, etc. They have been carefully looked after and stored.
Also comes with a 2nd...