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
Pubul57 - I used to have an Audio Aero Capitole MKII SE CDplayer with built in preamp connected directly to my amp. I had to sell it to buy a new transmission for the car (ugh!!) so will be using a old Sony CD player with the Lightspeed until funds will allow an Mac Mini computer to act as source that'll be connected to a Pro DAC which will feed the amp.
It's nice to deal with someone with a HONEST and accurate estimate. No BS why estimates are constantly revised ... blab blab blab

LOL...*wink* *wink*
Kevin, I can't imagine you would not prefer the LSA over the passive built into the Aero, but of course you won't be listening to the Aero transport/dac either. Knghifi, we await your full assessment when you have had some time....hope you are not dissapointed.
RCA ICs finally arrived and here's my .02. LSA is a very good match for my system. For most of my listening, the volume control is between 8 and 9 o'clock and 11 max.

My 2 sources are MW Transporter rolling 6sn7 and TRL Sony SACD player, EW Andra II speakers, TRL Samson mono amps and all ASI Liveline cables with several TRL power cables.

I find the LSA very transparent and detailed where complex and poorly recorded compress passages are easily deciphered. Excellent bass, big sound stage, extended highs and surprising excellent dynamics that plaque many passives.

Compare to my VAC Signature MKIIa preamp, in MY system, I find the VAC is in another league. Not 30x better but SUBSTANTIALLY better in every way. I CANNOT imagine selling it for the LSA in terms of sonics.

The boundaries around images are better defined and more separation from each other. Images and sound stage are much more 3D, layered and textured (I guess the magic of the Telefunkens), there is a sparkle to the sound, better dynamics where everything sounds tighter, airier and faster ... LSA sounds soft and 2D in comparison.

Probably not unexpected, I much prefer the Transporter than the TRL Sony with the LSA having some tubes in the chain. With the LSA, I prefer rolling the sweeter sounding Sylvania 6sn7GT "Bad Boy" and Shuguang BT CV181-Z with the VAC.

Bottom line, LSA is an excellent preamp regardless of price. I could easily live with it as my only preamp as long as I don't play the VAC back to back :-). I was looking for a cool running SS preamp for the hot and humid summer months and the LSA will fit the bill nicely with only a little sacrifice.
Knghifi, glad you found the LSA a good listen. There is something that a good tube preamp does that is very enjoyable indeed, and the VACs being some of the finest. I went back and forth quite a while with my Joule 150 Signature Edition (which is supberb)but for my taste, I enjoyed the LSA every bit as much, so for the price difference I could not justify keeping the Joule, given that I have the Atma-sphere combo for cooler months. The LSA/RM10 I will use in the hot and humid Baltimore summers. I guess what I'll say for now, is that the LSA/RM10 combo is a killer pre/amp combo for less than $2,500 where 35 watts is enough power. If I were an audiophile on a limited budget it would be my number one choice, and with the right speakers maybe where budget is no limit too.