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
Hopefully will have it in a few weeks. Ed Schilling at the Horn Shoppe builds them one by one and he has a bit of a back log right now. I'll probably start a new thread at some point in the future to provide some feedback and comparisons.
You must be joking. I've just heard the lightspeed attenuator in shootout with the Firstwatt B1 and the B1 killed the lightspeed in terms on dynamics. In fact I could not recall a single aspect where the lightspeed would be better. These are my thoughts only and do not necessarily represent others.
Clipsal, what were the other components in the system in which you heard the shoot out?

The B1 is an excellent product. Nelson Pass also has published schematics for his own version of the Lightspeed. My take on his development of the B1 is that through the use of an active buffer stage the preamp matches up much better to the low input impedance First Watt amps he designs.
Not joking, but of course system matching is key as Anthony. Love Pass gear, and heard the B1 at RMAF and it was very impressive. But so was the Bent TAP-x and I prefer the Lightspeed in my system since it is ideally suited for a passive with no impedance or gain issues - and far simpler device for minimal distortion. I have no doubt the B1 will perform better in some systems than the Lightspeed, but the reverse is true to, and then there is personal preference which is more difficult, if not impossible to account for.
Clipsal

I also would like to know the poweramp used in this shootout and also the CDP or DAC.

Cheers George