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
"...however some desire one for the resulting sound benefit they perceive in their system..."

Yes, some people like an added coloration, and there is nothing wrong with that.
I agree, there is nothing wrong with folks liking coloration that please them. I would just say that on principle, I would want my preamp to offer as little as possible so I can use it with alot of different amps and speakers with different voices - that is, the more nuetral the preamp the more equipment it can work with sonically. That is just a philosophical decision and preference on my part.

Interesting that Sam paid full price and then decided to get an LSA for his son. Not sure about Sam's wants, but he does NEED to be excited about new products if he wants to keep writing:)
At full price the LSA isn't going to break the bank. It's a very low risk proposition. That's one reason I like it so much. Of course that it works optimally in my system is another.
Jdec, it may or may not be. Remember, the end sound from your speakers is the sum total of all the parts in the system. Every single footer, wire etc...has impact. No two systems will ever sound identical and the end result may or may not have more added coloration then another system.

Like Sam said sometimes an active just helps a system sound more like natural music with wonderful tone and ease.
Sometimes a passive does this also. More than one road to accurate music and a passive is not the ONLY road to this end. All systems and gear have a sonic personality within a given system - all gear with no exceptions.