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
Sorry to go slightly off topic here. Don't want to derail the direction this thread is currently going but....I just have to say something. Something that you all already know. After spending a few months listening, nothing, and I mean N-O-T-H-I-N-G I've heard in audio has made me shake my head in utter disbelief more than listening to music through the Lightspeed. Put simply, after listening with the Lightspeed, EVERYTHING is overpriced. Just had to get that out to anyone unfamiliar with this preamp. You may continue with the thread...
Devilboy, it is great when you find something like the LS in your system that really works perfectly and exceeds all your expectations. Very excited for you!

I tried the LS in another system and it simply did not work. But reading everything here I was tempted to try it again with my new amp and speakers. I am always open minded and just had to give the LS another try.
I purchased one a few weeks ago and inserted it into my system. My new amp has an input impedance of 475k ohms and I actually measured it at 570k ohms! My new speakers are also relatively efficient so I felt I could give the LS a real chance to sing!

Well, I put the little LS on top of my 70 pound reference preamp and gave it a second whirl. I took notice immediately as my music sounded wonderful .
Dead quite background with nice tone and no hint of grain or any type of nasties. Nicely detailed and certainly earned my respect. For $500 and in the right system, the LS is a bargain of large proportion.

After several weeks of longer term listening I have come to respect this little passive. I would go as far as saying it kept pace and even bested some big dollar active preamps I have heard. Actives that sell for several thousand new. However, in the end I sold it as my tube preamp just surpassed it in too many ways. While my preamp costs $4000 new, compared to the wonderful LS it is not overpriced considering the improvement it brings to my music collection.

So I would not say all high end gear is overpriced as good values do reside in other places. I do agree that we must be careful as it is indeed easy to overpay in this hobby.
I thought "everything" was over priced when I heard the $135 Pot-in-a-Box (expensive Noble pots used on the vintage Audio Research SP-6) sold by Roger Modjeski. Given my two line stages at the time were in the $5-7k range a few years ago, it seemed like a bloody good deal! The LSA just happens to take a "simple" passive volume control to the nth degree, and as you have discovered, in the right system can be a pretty magical way of controlling volume.