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

Showing 14 responses by glory

I have a OTL being built by TRL and have a Lampizator level 3 Dac from Poland. IC is JPS Aluminata that is 1.5M. Will the LSA work in my setup?

How do I get to run my TV/BR with this unit?
Have a Placette passive Pre and would like to know what the LSA adds to the mix.

Open to buying one and doing the A/B gig.
So going to order this LS. My Placette makes noise for some reason when plugged in.
So going to order this LS. My Placette makes noise for some reason when plugged in.
Ok phone a friend.

I need to order a battery for the LS. Who has the right battery and where/who did you buy from.? Need the sellers name. Hope it's from Amazon in the US.
Well well we have a winner here in the crib. Will report further truth shortly.
King,

The LAS did a way better job of letting me hear my Lamp L5 than the Placette. My goal here is for the VC/pre amp not to alter the sound of this great 3D sounding Dac. I am sure an active pre would give me a more .... Sound and add to the mix but the L5 has enough of all that so there is no need to add any other ingredient to the system.

The LSA is noise free and simply passes the L5 sound to my amps. I have a 3D sound stage if it's recorded as such. Not flat or 2D as that is not what the L5 is about. So the LSA guy is giving me the Lamp sound I know so well that the Placette just couldn't do.

So I hooked up some ASI LL SC/IC's to my system and it was an ear opener. I will keep them hooked in as they work well with my amps/speakers.
How long do I have to wait to see my post showing up when written. 2 days ago?
LDR products from Tortuga has a remote and my wife needs one. Has anyone compared the LSA to the Tortuga?
So Tortuga is doing the same exact build as you but with a remote and gets $1.2K for their unit?