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
Hey George, yeah the iFi just hasn't done much for my Lightspeed in my system. I feel like my system is resolving enough to pick out a bad recording pretty easily and to hear differences in cables, but I just couldn't spot the changes from this ultra quiet power supply if they exist. I almost felt like it made things a touch more reserved compared to the linear wall wart, but there is no way i could blind test prove it.  That was probably pyschological negativity toward a change on my part.  I like a lively system. I'm actually using the iFi right now and there is nothing wrong with it, just not a noticeable change for me.   My system doesn't have super sensitive speakers or a room designed for extremely critical listening though. I would be interested to hear about the iFi from someone with a very revealing system and dedicated room.  
Glad to read the iFi iPower DC supply being discussed. I’m interested in using it in place of the as-supplied Auralic Aries Mini wall wart. I wouldn’t call my system extremely resolving, though I can easily hear changes in cabling. I could not, however, hear a benefit using the Audioquest Jitterbug. But, for $49 bucks from Music Direct and given their 60 day return policy it might be worth trying the iPower device. More likely to spend $49 as opposed $299 for the Auralic LPS. Am wondering if anyone other than mward has tried it. Tried searching discussions, this Lightspeed Attenuator thread was one of only two that came up. Thanks in advance for any input.
This Lightspeed sounded open, relaxed and showed me all  musical info that I have been missing for a long time, a real game changer..AN Dac 3 fed by msb digital cd rom drive into lightspeed then the CAT JL2...endless power and dynamics and i have not even matched the
impedance between devices yet...
soundwise
endless power and dynamics and i have not even matched the
impedance between devices yet...
Hi Michael, looked at your source and amp impedance's, and you have a nice impedance match.

BTW: what speakers are you using, as the rest of your system looks very nice, though I'd hate to have to fork out for 12 x 6550's when time comes around.
The ones I used to love were the military NOS G.E. green label ones, who's glass seemed twice as thick as anything else, and they cost over $200 each if you can find them new in box in Australia.   

Cheers George
Verity Sarastro 2 ..they took the Raven Ribbon tweeter apart and added better magnetic parts and also shortened the ribbon surface to widen the dispersion pattern. These speakers with the cat amp are very nice together..best for acoustic instruments.