I have a set of these tubes in my Modulus 3A that I got from Upscale Audio. They sound fantastic! They are much more dynamic than the stock tubes although maybe not quite as quiet, but not near as noisey as NOS tubes. I have compared these tubes to NOS tubes in my unit and I prefer the 6H23's. I only paid $25 each for them. I highly recommend this tube to anyone that has a Modulus preamp.
