2. amps-preamps
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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 2 responses by sibelius

sibelius
256 posts
 
For those of you who have been around the boards a long time, this looks very much to me like a much hyped passive preamp of old called the Morrison ELAD. I remember the buzz - the ELAD was the closest to "straight wire with gain" that you could get. I bought one. Well built but sonically did nothing for me. Fast but cold. No emotional connection. However it was good lesson. I learned that I prefer the warmer sound an active preamp over uber transparency.

I have not heard the lightspeed so I don't want to be critical. I hope its owners are happy. I will say that the price point makes it attractive to try out. $500 these days in audio is not much of a gamble. Just seems like we may have been down this road before.
sibelius
256 posts
 
I stand corrected in my Morrison ELAD comments. Thanks for the clarification Georgelofi.

I agree with Pubul57 that for many the straight wire with gain approach is as much a philosophical stand as anything else. I was once one of those folks. Then I became heavily involved with tube amps and preamps and my approach softened. I am aware that a SET tube amp most likely "colors" the sound of most recordings I hear. However,I've made peace with that because I greatly prefer that sound. The issue I have with some "straight wire" proponents is that they can take their stance to the extreme by believing they are recreating live like music conditions via their stereo systems. A quick trip to the symphony is a more than subtle reminder that even the best stereo systems I've heard (Shindo,Audio Note etc..) are nothing more than crude approximations of the real thing.
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