i have a moderately recent american version and a modded russian version designed for smashing pumpkins fans (creamy dreamer) and what i've found is that the russian muff seems to be designed for better sound at lower volumes. the russian version does sound clearer and more usable here, but that's why. it has to do with the way a muff works. it's supposed to be plugged directly into a tube amp at high volume levels. this test is consequently largely useless.