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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
grannyring's avatar
grannyring
6,519 posts
 
I forgot to add that my Soundlab speakers are very revealing and I would not consider them warm sounding. My Atma-sphere amps are also quite revealing and I would not consider them warm sounding. The LSA is also very revealing and with it in my system the net result may be to much of a good thing - transparency?

Just a thought....
clio09
3,360 posts
 
Thanks for your comments Bill. I'm glad you enjoyed listening to the LSA. I'm missing it myself so I'm also glad to hear it will be returning to its home:)

I find your last comment on the potential for too much of a good thing an interesting one. I've sometimes felt that depending on various components being assembled, this can occur. I also sense a difference using the LSA with my Atma-Sphere versus my VAC amps. The former combination is much more transparent, the latter adding a touch of warmth and bloom to the mid-range. I'd say my Music Reference RM-10 MkII is somewhere in the middle, closer to the Atma-Sphere than the VAC. I enjoy all the presentations. One not necessarily being better than the other, just different.

Personally, ever since I listened to my first passive preamp (a custom built K&K Audio TVC) I have felt active preamps are additive (some may offer more transparency than others, but in the end they are adding something to the mix). I even felt this way with my old TRL preamp. In the end that's just my opinion and I'm sure there will be some disagreement on that from others here as we all have our preferences.
grannyring's avatar
grannyring
6,519 posts
 
I should also point out that the LSA is a champ at bringing all of the detail and parts of the music into the front row. I was hearing instument lines that on my Dude were more muted or set-back. Some may really like this. This is what really got my attention in the first hour or so of listening.
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pubul57 OP
3,712 posts
 
I have no doubt the LSA is truer to the source than any acrtive linestage. Whether being true to the source sounds better or not to a particular listener is another question that nobody but the listener can answer. What I think the LSA offers, is the ability to eliminate a step in the chain, so that you are left with source,amp, speaker to define the system's sound - it simply gets out of the way, and the source - amp - speaker interface is free to define the sound, without the the preamp acting as a chameleon with differtent systems, the LSA simply gets out of the way, better than any other preamp I have tried, and that makes it transparent on not a coloration to be played with in the system as a whole. Because it is so transparent, or absent, it will alter the choice one might make between source and amp - but for what it is designed to do, it seems to me it does it extemely well. You want warmth, change your amp - the LSA does nothing but make the music louder or lower - don't expect it to flavour the soundscape in any way - it won't do that - it is the color of water.
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