2chnlben, I haven't contacted Rick yet because I'm not convinced the DAC is a problem. I want to test different cables and sources first to see if I can soften the edges. The stock DAC was sharp to my ears to begin with, so it may just be the nature of the unit itself - regardless of the mod.
I don't want to give the impression that the mod is a negative. Point in fact, I find the moded DAC more listenable than the stock. If you like the stock sound of the PS Audio DAC 3, the upgrade is a fantastic value. Seriously, I haven't heard many other pieces of equipment that reach this low with such clarity and tightness (at least, not at this price point). All things considered, I think the Cullen mods are an exceptional value for what you get.
However, between the aggressive nature of my other equipment (Manley Stingray, Nordost Blue Heaven cables) and my sensitivity to the bright edges, I may have to go a different direction.