The 735s have barely been broken in, with less than 100 hours so far; I suspect that the Lundahl input transformers take an especially long time (1,000+ hours) to break in.
Let me start with the good news:
1) The form factor and input/output connectors are identical to the 725S2s - making the transition seamless and simple
2) The finish on the non-anodized cover is beautiful; the mirror-like but satiny surface which diffracts light in a seductive way that is elegant is very First-Class
3) The small on/off button and correspondingly small white LED is both easier to actuate and cute/elegant. The soft turn on/off circuitry eliminates the loud raspy burst of random noise - but I'm not sure what audible penalty there is the insertion the muting circuit - is it 100% transparent, sonically?
4) The ultra-annoying (and inexcusable) clicking and clacking noise emanating from the power supply of the 725S2s located near the XLR inputs, audible from even three feet away, is GONE - FINALLY !!!!!
Some things that may be worth fixing:
1) The flat/thin "isolation" pads stuck at the bottom of the chassis is awful, in terms of user-friendliness; 1/4 inches is not enough clearance to accommodate one's fingers under the chassis, making it impossible to grab and lift the chassis intuitively and securely. Grabbing the heat sink at the top is an alternative, but that doesn't prevent the chassis from constantly bumping against the substrate shelf material every time the perimeter of the amp is touched (even gently).
2) The XLR signal inputs were wired out-of-phase (pin 2 and pin 3 were reversed); hello, QC !
Sound-wise...
1) Caveat - still in its early days. The 735's bass is relatively deeper and punchier, but this frequency tilt seems to mask out some of the upper-mid to high frequency details, rendering the soundstage flatter and smaller. Cymbals and metallic strings lack "bite".
2) The expansive and holographic imaging of the 725S2s - I can't hear it in the 735s (yet). The size-appropriate imaging and attack/decay of the fragile, scintillating ambiance attack/decay envelope in music is the product of correct amplitude and phase. I'm not sure whether the purported benefits of the new materials (and winding?) in the input transformer is an improvement over the old version.
Again, early days... but my expectations are (justifiably) high for these $40,000 pair of monoblock amps, as it's supposed to be JRDG's flagship Class AB amp, incorporating decades of evolution and refinement in components, design, and execution. Fingers crossed that over the next few weeks, the performance gap will not only close, but exceed my 725S2's.
