Lightspeed Attenuator - Best Preamp Ever?

The question is a bit rhetorical. No preamp is the best ever, and much depends on system context. I am starting this thread beacuase there is a lot of info on this preamp in a Music First Audio Passive...thread, an Slagle AVC Modules...thread and wanted to be sure that information on this amazing product did not get lost in those threads.

I suspect that many folks may give this preamp a try at $450, direct from Australia, so I thought it would be good for current owners and future owners to have a place to describe their experience with this preamp.

It is a passive preamp that uses light LEDs, rather than mechanical contacts, to alter resistance and thereby attenuation of the source signal. It has been extremely hot in the DIY community, since the maker of this preamp provided gernerously provided information on how to make one. The trick is that while there are few parts, getting it done right, the matching of the parts is time consuming and tricky, and to boot, most of use would solder our fingers together if we tried. At $450, don't bother. It is cased in a small chassis that is fully shielded alloy, it gets it's RF sink earth via the interconnects. Vibration doesn't come into it as there is nothing to get vibrated as it's passive, even the active led's are immune as they are gas element, no filaments. The feet I attach are soft silicon/sorbethane compound anyway just in case.

This is not audio jewelry with bling, but solidly made and there is little room (if any) for audionervosa or tweaking.

So is this the best preamp ever? It might be if you have a single source (though you could use a switch box), your source is 2v or higher, your IC from pre-amp to amp is less than 2m to keep capaitance low, your amp is 5kohm input or higher (most any tube amp), and your amp is relatively sensitive (1v input sensitivity or lower v would be just right). In other words, within a passive friendly system (you do have to give this some thought), this is the finest passive preamp I have ever heard, and I have has many ranging form resistor-based to TVCs and AVCs.

In my system, with my equipment, I think it is the best I have heard passive or active, but I lean towards prefering preamp neutrality and transparency, without loosing musicality, dynamics, or the handling of low bass and highs.

If you own one, what are your impressions versus anything you have heard?

Is it the best ever? I suspect for some it may be, and to say that for a $450 product makes it stupidgood.
I would put the lower one from the Lightspeed to the amp. Saying that what were the pF measurement for what lenghts of the both cables you have? And then I can then give you a -3db HF roll off point in khz.

Cheers George
I just saw in your previous posts that the capacitance you have is so small on both cables it does not even factor in which goes after the Lightspeed.
As the Blue Jeans at 2ft you have at 13pf per foot will be -3db at 874khz!!!
And the Bryston cable you have at 3ft at 21pf per ft will be -3db at 541khz!!!

As you can see it will not matter as far as the -3db roll off point, just what you prefer the sound of in which position.

Cheers George
Cool, Thanks George,

My new 2 foot cables (Blackcat Lectraline) are 37 pf/ft so a negligible change
Yes, Photonman it's only when the cheaper cables get over 100pf per ft and a meter (3ft) or more long things can start to happen.
eg: a bad quality high capacitance cable of say 100pf per ft and 1mt long would be -3db at 76khz which still fine but you get the picture.

Cheers George
Ok phone a friend.

I need to order a battery for the LS. Who has the right battery and where/who did you buy from.? Need the sellers name. Hope it's from Amazon in the US.