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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
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banquo363
371 posts
 
Teajay: I see you own the Concert Fidelity preamp. I heard it at last year's THE Show in the room where Clio09 was working. Amazing sound. If I could only locate the $20k I misplaced, I'd happily replace my LSA with it.

I just read Arthur Salvatore's review of the Coincident Statement Line Stage. He mentions the LSA as a possible player in the best preamps sweepstakes (although he hasn't tried it himself). He mentions it despite advising against all resistor based passives--the LSA is one of those, right?

Unlike the CF, the Coincident is within reach (for me) and is tempting because I know my phono stage has a higher output impedance than is ideal for the LSA. It nevertheless sounds superb and I don't know if I'm missing out on anything, but one always wonders. Too bad their phono stage has too much gain for MM carts.
clio09
3,360 posts
 
Maybe Arthur's been reading this thread;)

I had the pleasure to work the CF rooms at 3 shows now and will be there at RMAF this year with them. I have probably spent close to 150 hours listening to those components as a system with a variety of speakers. The result has always been great sound.
georgehifi's avatar
georgehifi
10,312 posts
 
Hope all the testosterone has now been depleted.
Your question Unsound:George, perhaps you would discuss the balanced issue?:Unsound

Balanced can be done, for the diy'ers, but to manufacture it, it would be a nightmare, as to do match a quad set which the production Lightspeed Attenuator has, is already very time consuming. To do a double of this for a balanced setup is exponentially harder and costlier and may drift.
Not impossible for the diy'er though as it could be self calibrated. every few months by the builder. I have posted the circuit for a balanced here on diyaudio, you may have to sign up to open the attachment though.
http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp-383.html#post2396316

Cheers George
teajay
1,702 posts
 
My dear Fiddler,

Thanks for your kind words towards my self description. Remember any time you want that autographed picture for your wall, please let me know and I'll ship it right out to ya.

Happy regards from "THE ARROGANT BASTARD"
teajay
1,702 posts
 
Hi Paul,

Yes, your speculation regarding my use of SS amps (Threshold&Pass Labs) with a tube based preamp in my system vs your use of tube based amps with a passive preamp makes sense to me. You get what tubes have to offer the body of the harmonic, soundstage layering, and at least for me with the right tubes more natural sounding timbres with your power amps and I get it out of my tube based preamp and tube based DAC.
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