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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
clio09
3,360 posts
 
Sorry, itchy trigger finger.

For some time I had been a big proponent of transformer based passive designs. The Lightspeed changed all of that and the idea of the thread was to really extol the virtues of resistive designs - done right IMO. Yes they do require more finesse in system matching than a TVC or AVC, but overall I think a well designed resistive passive is truer to the sound. Makes me want to go back and listen to a Placette again, I may have dismissed it to soon.

What I find with the LS is that the issue of soundstaging, dimesionality, apparent bass and highs, etc. is dependent on the recording, and for my approach to building as system, this is the way it should be...

To Pubul57's point, I've been hanging around a recording engineer of late. His system uses SET amps, a passive, preamp, and some pretty good source equipment and speakers. The speakers were placed against the back wall. One would think sound stage depth would suffer, but it didn't. It was however recording dependent and to his point, much (if not all) of the sound staging comes from the recording itself. I tried this at home with my own speakers and found it to be true. Amazing how much space I've created for stuff other than listening now that my speakers are nearly in the corners of the room.

I think equipment that is true to the source will provide the proper sound staging - regardless of whether they are active or passive designs (in the case of preamps). It really does come down to preference, but I know I'm not going back to an active preamp anytime too soon.
pubul57 OP
3,712 posts
 
Anthony, Roger Modjeski was gracious enough to explain to me why he thought resistor passive would be theoretically better than tvcs or avcs (the Audiogon consensus was that TVCs were far better than resistors, that TVCs 'blew them out of the water - which always seemed an overstament), but you know how he gets with technical explanations, he quickly lost me. When I had the Placette I like it very much, and I do think it might be fruitful to go back for comparison, but I suspect that the fact the Lightspeed has no physical contact points, no mechanical interface, no oxidation, no wearinmg out with time and swipes, might be an unbeatable advantage, even for Swiss crafted, jewel-like, precisely machined or lazer edged attenautor contacts:)
onhwy61's avatar
onhwy61
5,256 posts
 
I still say it's not a preamp! Any direct comparisons to other real preamps are somewhat misleading. Kudos to the designer/manufacturer for calling it what it is.
pubul57 OP
3,712 posts
 
Lightspeed Attenuator, Best device for controlling volume in an audio system ever? including "real" preamps?
tradeontheweb
43 posts
 
In regards to comments on the Morisson Elad.

I too read the hype a few years ago and searched long and hard to find one. I then had a custom power supply built to suit our 240 Voltage here in Australia.

I had it in the system for several weeks, constantly A-B'ing against the LS. The best overall description I can give the Elad was it just sounded "duller" in all areas. This was irrespective of cabling lengths or impedance matches/mismatches.

However, I sold it to an aquaintance who still uses it to this day and actually prefers it over my LS, in his system !

As stated elsewhere, the LS is not for all and can be a harsh taskmaster indeed. It will make you "lift your game" and requires your whole system to be in order, to show it's best.

Easily worth the effort - IMHO
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