Music First Audio Passive Magnetic Preamplifiers?

I second Clio9's recommendation of the Lightspeed Attenuator which is a real steal new ($450), not sure what the one up for sale cost. I have used the following passives Placette RVC (and "Active"), BENT TAP-X autoformers, Goldpoint, Music Reference PiaB, and K&K TVC with S&B mkIII transformers. The Lightspeed is as good as any passive I have used in my system and it just possible I might keep this as one of my preamps till it stops working 50 years from now. Single-ended, and one input only (part of the reason it sounds so good?). Saying that, all of these passives will sound very good to excellent with sensitive amps, short ICs, and 100kohm amp input impedance.

I think they are very similar in mids and highs, where I find the LS amazing is in the quality of bass and dynamics - not that the BENT is a slouch, but I wasn't expecting it from a resistor based passive which needs more careful system matching than the TVC. If the quality of the attenuator is of extreme importance, not sure how you can get better than no contact (light) control of resistive values and related attenuation of a signal. Clio9 is far more articulate than I and has done more A/B listening to passive, my listening has been sequential so my comments are more impressions based on memory. Clio9 has done much more heads up comparisons. I can only say I love the Lightspeed in my system and I never quite felt that way with previous passives - though I certainly though they were very, very good and exceptional value compared with actives of anywhere similar quality. I would like to hear a LS attenuation control within my active tube preamps (Joule and Atma-sphere) - it would interesting hear this purist of attenuators to control volume within an active environment.

George, you have been working on this for a few decades, any ideas cooking on how to make the Lightspeed better yet, or is there nowhere to go at this point? Isn't your idea patentable?

DIY is no threat, since that community is going to reverse engineer this stuff anyway, for electonic dopes like me, I am more than happy to pay George, have him make a profit on what is simply an amazing sounding piece of gear, and a SOTA, single input preamplifier that can compete with any preamplifier in the world with careful system matching between source, pre, cables, and amp. Not for everyone, but in the right system about as good as it gets IMHO.

George, is there any improvement to be had with the chassis and shielding and/or vibration control in a way that might make any audible difference (not just "pride of ownership" bling?

The MFA is said to sound very much like the BENT Audio passive when it used the S&B transformers, I thought the Slagle autoformer version - the BENT TAP-X - sounded even better if you can believe it, and better yet the Lightspeed Attenuator. Given the equipment you have been listening too, I know you could easily try the LSA - not full featured or anything, but for sound? I've not heard a better passive.

MFA is certainly a more flexible unit, as are the BENTs.

You think?