Well I guess I'll chime in here. First, I've used the Job without a preamp before. I connected the Metrum Octave's outputs directly to it and controlled the volume with my itouch. However, because I run PureMusic, I heard a very audible, very annoying hiss at low to moderate volumes (this is not to be confused with the humm/buzz I initially heard with the Job due to its grounding issue which was ultimately resolved with a simple rewiring from a service tech in NY).
I think the problem with running amp direct from my DAC was due to the Job's very high 35db gain and .75 Volt sensitivity. My buddy brought over his amp which is 26db gain and 1.86 volt input sensitivity and we herd nothing....no hiss whatsoever. So, keep the Job's high gain and input voltage sensitivity in mind if you go amp direct. I don't know if the Oppo has volume control. I'm assuming it does.
I've used the outstanding Lightspeed Attenuator LDR with the Job for about three weeks. During usage, I found it to be very transparent and open with the Job. However, it wasn't until I received the Bent TAP-X autoformer two weeks ago that I realized the LSA sounded a bit flat and heard a "lack of drive" if you will, with the Job. I think what I was hearing with the LSA MAY have been due to it's high output impedance going into the Job's 51K ohm input impedance. Now, 51K is slightly above the industry standard but in terms of passive preamps with very high output impedance, it may be cutting it too close, IMO. If the Job's input Z was 100K or over....different story.
Again, the LSA is an outstanding product and is one of the best bargains in audio. However, as good as the LSA is, the Bent, in my system, is THAT much better. More open, transparent, holographic and the biggest difference: it sounds more effortless with the Job. I think it's due to the autoformers not having impedance mismatch issues.
I know of the product from tortuga audio but have not been fortunate enough to hear one.
