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
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.
marqmike
844 posts
 
Hey, hey , hey guys. I personally like the LSA to anything I have ever heard, which you can see most of that is on my previous posts. I have experience with real musicians in real space and real time. And from that perspective I find on most non-musician friends and others systems there is to much concern with the 3d thing and spacial ques, it is out of proportion to what I find in real space. And I feel it effects the tonal response of the whole recording and the timber of the instruments and voices. I say sure you can hear a fly land on the back wall of the auditorium but that is not what I listen to a recording for. But the truth is we all live on our own worlds when it comes to music and its reproduction. And that is fine and good.
teajay
1,702 posts
 
Hi Paul,

Something else I wanted to share with you but I forgot to mention, is my experience with many tube based active linestages is that the ones that use a rectifier tube in the power supply sound much more natural/musical to me then preamps that are totally SS in this section of the power supply. Again, I don't know why this should make that much of a difference from a technological perspective but my experience has been that it sounds much better then a SS power supply.
pubul57 OP
3,712 posts
 
Terry I have heard that said about power regulation and believe it, my experience too - seems like those old technologies seems to still work pretty darn well:)

I do think we are on to something regarding passive and there use with SS versus tubes (in addtion to the fact that SS will generally, but not always present a more difficult impedance load). I always wonder about folks that have tried passive and find something lacking (besides noise:)) - I always thought that some of that must occur if the impedance/gain/IC capacitance issues are not properly. Now assuming all that is fine, than I can see why those using SS amps and no tubes in the chain might also feel something is missing (and it may very well be a form of distortion - but one I like and makes me happy). Oh, well, play around with this stuff is [more?] hald the fun!

Marqmike, I too find that much of what we look for in recorded music through our systems regarding 3D, imaging, spacial cues, etc. is simply not there in live perfomance, or at least far less than we seek it in our systems. What live music brings that no stereo system I've heard truly replicates is timbre and dynamics - every time I go listen to unamplified live jazz, I go home and remind myself to accept that while I love my system and listening to music on it, it is not the same as live (really, how could it be?) but a facsimile.
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