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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
pubul57 OP
3,712 posts
 
Arthur Salvatore also says, in an interesting way, that if your systems sounds better, in any way, than a direct connection or passive, then your system needs and active preamp (he says most systems do) - because in some way your just not matched right. AS' views is that passive is the best, unless you need active. I'm pretty sure my system does not need an active for gain or impedance matching and therefore it is unlikely that any active preamp or volume control/gain device will improve over what essentialy (as George points out) is as close as you can get to a direct connection between my source and amp.

If amplyfying that signal through additional wire, capacitors, transisitors or tubes etc, only to attenuate that additional gain can some how improve on the original source signal, I just don't see how it can do that unless that signal needs all sorts of conditioning to drive the ICs and amp. My 2v or 3.9v outputs from the EMM Labs CD player don't need such help to drive the amps, and if there is dimensionality and warmth in a recording it is there at the output of the CD Player, not fabricated in an active tube or SS linestage - and if it is the byproduct of the linestage, I don't want to hear that as it will be an overlay on everything you listen to.
grannyring's avatar
grannyring
6,519 posts
 
Actives can sound better to some because they like the change those tubes, caps etc give the sound. Yes, a good active tube preamp may in fact change the sound and that can be a great thing for some people.

Larger stage size, more romance, or even a greater sense of ease to the music can be (ADDED) by a tube preamp. Some like that.
pubul57 OP
3,712 posts
 
You can't argue with what people like, which is the only criteria that is important. I suppose the straight wire with gain approach is almost a philosophical stand, even when that might not necessarily result in the most enjoyable sound, a bad recording has no place to hide. This is proabably an issue that can never be resolved, there simply might not be a right or wrong here.

The Lightspeed does minimal (even compared to other passives) alteration to the signal (noise, distortion, bandwidth anomalies) and does this very well, if that is what you are looking in volume control (true to the source) it will serve you well.
grannyring's avatar
grannyring
6,519 posts
 
We are on the same page Pubul57. Your comments are well thought out and educational.
clio09
3,360 posts
 
Active preamps are for the most part tone controls (a good case could be made that all components are tone controls as well). A good example to reference is the Audio Horizons thread. A number of people chose to take the very well received stock unit further through modification (whether through the factory options or their own doing). The idea was that they wanted more or something different from the sound of the original unit. Fair game, in a way that is part of the hobby and can be very enjoyable, whether you're swapping tubes, caps, wiring, or whatever else can alter the sound.

What is somewhat amusing to me is that some people want tone controls (bass, treble, etc.) on the tone control itself. I guess a little is not enough in those cases.
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