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.
pubul57
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You may or may not like it better than your unit, we all know that we personally gravitate to what we want, what we like, and what anybody else says doesn't really matter, IF we can trust our own ears and preferences, all I am saying about this preamp (semantics aside, I don't need a source selcetor) this thing is special in away that the other passives I have tried have not been able to match, and obviously has gone up against some pretty renowned tube preamps where at least some folks have concluded that it is preferable. So all I am saying is that as we seek the best sound avaialable, this $450 peramp (thing) is worth a try, even if at the end of the day you decide to stick with your active (tube?) preamps.

Maybe George HiFi will be able to figure out a trial scheme that can make sense to him, though he may already may be limited to how many he can make per month so I may be a moot suggestion. While I will use the Atma-Atma combo with balanced cabling, my other systems combos are going passive with the Lightspeed.
You must order directly from the maker in Australia. A google search will help you find him. I get the feeling he is an individual making a few of these and he pursued this without the idea of starting a real business, but word-of-mouth has proabably driven more business than he expected, so I have no idea how long it takes form him to make and deliver, especially after Sam Telligs review which essentially reached the entire North American audiophile community. He does have a minimalist website.