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
George, the cheaper the product the greater the customer service demands. Don't know the name of that law, but it seems to apply across industries. It would be good for you to be able to include the wall-wart with the shipment, though I guess that can get crazy, but I assume the US would be a pretty big market. $1000-#1500 with multiple inputs and a more substantial, fancier chassis should have a strong following amongst the passive set. Congrats on the ongoing Stereophile recognition.
Goldpoint does a very good job of providing a classy, no-nonsense case for their array of passive preamps.
220v/240v wall warts are supplied to most countries except the U.S. which is unfortunately 110v. (Just like you guys also drive on the wrong side of the road compared to everyone else).
I refund $15 to those customers and give them a few links to get their own in the U.S. on line.
In Australia it is a safety issue to sell or supply or import 110v wall warts, on suppliers sell them, as you can imagine if one were to be given 240v it would become a molten mass very quickly.

Cheers George
Devilboy: George, are you joking? Some actually complain about the cost of the current unit? Devilboy

I am serious, here is one reply email from yesterday, and I'm ashamed to say he was from Australia as well.

" Hi George, Thanks for your reply. It's very expensive. I've to save money for this. J"

Cheers George
Well even at it's price point I guess not everyone can afford to own the best preamp ever:)