I have received my OR4 with the OTL mod ( same one which Steve showed the jitter plots earlier in the thread). The OR4 has dual Turboclock and USB Hynes reg. Output is Via BNC plug to BNC input of Audio Research DAC8. Downstream of that is Conrad Johnson ACT2, CJ Prem140 and Dynaudio C1. All cabling is Kimber Select (1030,1036,3035), except Steves new BNC-BNC digital cable. Source is a modded 2011 Mac Mini with SSD, fanless, Wifi and Bluetooth antennae removed, external DC linear power supply, Mountain Lion and Audirvana+, Kimber Ag Bus USB cable.
Steve also sent me one of the smaller wallwarts to replace the one issued with the OR4.
When I installed the modded OR4 I could immediately hear a dramatic improvement. It is particularly noticeable on high quality recordings like Madeleine Peryoux Careless Love (44.1/16, on the fly upsampling to 88.2 in Audirvana).
I would describe the improvements as consistent with what the standard offramp does, but taking it to a new level. There is a significantly improved soundstage, and overall a more realistic, natural sound. The improved realism of piano notes is quite noticeable. Seems like the new OR is capturing the transient of the piano notes better.
I havent yet tried swapping back the old wallwart or my old digital cables (Kimber 2020 0.75m and CanbleDyne Silver 1.5m). I will report back when I try these swaps.
The next upgardes I have in mind are: Steves new Hynes power supply for the OR when it becaomes available, Better quality power supply for the mac mini (thinking about Teddy Pardo 12/4 supply), and a higer end USB cable like Audioquest Diamond.
For anyone with an existing OR, the new mods are strongly recommended. The improvements are not subtle. It feels like an improvement that should cost thousands, not hundreds of dollars.