lme 49990

A lot depends on other components but the ha (small metal can housing dual opamps) had been the subject of much oohing and aahing prior to release of the lme49990.  Then, based mostly on outstanding specs, most attention shifted to lme49990, which like the lme49710ha contains a single opamp.

The best way to compare them might be to participate in the GB over at diyaudio for one of the lme49990/lme49600 head amps and then order what eBay's Jim's Audio calls their "Low distortion ( 0.0001%!) preamplifier headphone amp !".  Both require separate power supplies.  Both use the LME49600 for the final stage (Jim's uses dual LME49600 and an LME49710ha) whereas the se-se and bal-se boards at diyaudio use the LME49990.

My own interest has been in using a bridged pair of Jim's boards to drive rewired HD600s.  When the diyaudio boards ship I will be able to compare the bal-bal to the bridged pair.  Keep in mind that the component count, and hence cost, for a pair of Jim's boards is twice that for the diyaudio bal-bal.  I expect to  discern little or no difference.  YMMV.

The bottom line is that I will be making the comparison but have not yet done so.  The pair of Jim's boards bridged sounds very good.  Certainly better than a pair of discreet JC-2 clones similarly bridged.