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
No, it is the recording my preamp has more fidelity to, not distortion etc... I have heard Van Morrison live on many an occasion and the weight and heft of his voice is missing on the LSA compared to the active.

Sorry, but them there are the simple facts in my system.
Paul, I'll be attending the party for a little bit this year seeking out some folks to say hello. I'll be getting over to Del Frisco's Double Eagle Steakhouse as well. There's a bottle of Silver Oak Cabernet with my name on it courtesy of friend. Can't miss out on that.

Some good after hours events in the rooms too. Thom Mackris from Galibier Design (I use his Serac turn table) is doing some fun stuff. I'll be staying in the Concert Fidelity suite as their guest, so I'm sure we'll be keeping the music going a bit past 6pm. It should be a very well attended event.

Keep CES/THE SHOW in mind. If you've never been to it this is a great time too, although somewhat more exhausting than RMAF. We have a Del Frisco's here too:)
Grannyring, "it is the recording my preamp has more fidelity to" - more fidelity than the LSA in your system? -- that is very possible. What seems impossible is that an active linestage could have more fidelity to the recording than a direct connection (with no impedance mismatches, and no ICs), I suspect that in your system, for some reason, you would hear a difference between the direct connection and the LSA connection because something is just not matching right - now, if it sounds the same then I just don't see how your preamp is truer to the recording; though I believe that Van Morrison live, in a large space, and amplified through a sound system is going to sound quite different than a studio recording or even a live feed from a live performance. The important thing is you have a preamp that you love and makes you happy; what it is all about.
Well said Pubul57.
If I could just add to that, as I tell many customers, a direct connection between CDP (non tube) and Poweramp is the best/truest transfer of what is recorded on the disc. And the Lightspeed Attenuator comes the closest to that direct CDP (non tube) to poweramp connection.

If an active preamp sounds better than this, then it is the system that has a problem and needs the coulouration of the active preamp to band-aid fix that problem, it would be better to fix the problem than to cover it up.

Cheers George
I've been following this discussion with much interest, and I feel inclined to chime in. . .

There have been several comments about the goal of our systems (preamps here specifically) being to sound like the live event. Bill just commented above about hearing Van Morrison live, and feeling that the LSA doesn't provide that experience.

I submit that the role of our systems is to reproduce the recording, not the live event. If the recording doesn't contain the appropriate information or is of poor quality, then by default, if it reproduces the sound of the live event it's coloring the sound. If I happen to like that sound, that's okay but I'm not fooling myself into thinking it's an accurate reproduction of the recording. The question then becomes, "what does the recording actually sound like?".

I think the suggestion is that the LSA provides the best answer to that question, all things being equal.

JMHO