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.
The Morrison Elad is just a normal active preamp using normal pot and a 50 cent Analog Devices AD797 opamp with no gain.
It has nothing what so ever in similarity to the Lightspeed Attenuator and it has nothing what so ever to do with LDR's or LED's.

Cheers George
Faziod Hi you will hear very low level of music at minimum level as this is the characteristic of ldr's in this design is they can never go to complete darkness or infinite brightness as these are the controlling factors for resistance. Think of it as there is no such thing as infinite brightness or infinite darkness.
Cheers George
Sibelius I have heard in my system the Morrison Elad and it is not in the same league as the LS. The other preamps I mentioned in an earlier post are all excellent passive's the LS is simply better.
Fazoid, I think you had the Bent TVC? An very good passive preamp. I've had Placette, S&B TVC, and Bent/Slagle autoformers, and a few others. While I thought they were all exceptional values with excellent sound, I nevertheless, ultimately preferred my active tube preamps that I owned at the same time. The LS is the first to make me think I may not need them anymore, though I may keep them for the same reason I keep 3 amps, I like audio gear:). This is not a poor man's preamp, though it is affordable to many, it is actually pretty expensive for what it is in terms of parts, but what you pay for is years of perfecting the basic idea and the painstaking matching of the components to get proper balance between channels. You could, I suppose build one of these with George's instructions found on the DIY boards for less than $100, for some of you with the skills that may be an option -- I'm sure I would manage to start a fire.....
La45, yes this was the one I started using a while ago, around Thanksgiving last year. A while back I started a thread called Slagle AVC Modules & Lightspeed Attenuator.