My experience in my Jadis tubed preamps (using Tubesox, Top Hats, Vintage Tube Service's brass dampers (the best of the ones I tried) and Mapleshade dampers) has been that the better tube dampers take away a little bit of that tube warmth but give a bit more focus and clarity to the sound. This would be consistent with lowering the tube microphonics, getting rid of a small amount of distortion. Given the commparatively inexpensive choices available to you with the Herbies and Audio Research dampers, you might just want to experiment and see if you like the sound better with or without.
