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
I've never turned my volume past 12, and most often have it at 10. Both vinyl and CD. What is responsible for having to turn it to 2-3? My ear drums would rupture at those levels.
sensitivity of amp, sensitivity of speakers, size of room, how loud you like it, and hearing acuity. now, if i switch the cd players gain to 4v, i never go above 12.
WTF... Is all this about short single ended interconnects.

I'm running 6 meters (18 feet) of Crimson cable from my BENT NOH Passive to vintage VTL Compact 100's without any problems. And unlike the Lightspeed the Bent (using S&B 102 mkII) has 6 inputs, 2 balanced and 4 unbalanced. Additionally I can add 6 db on the fly (which works well for my phono preamp).

As much as I would like to try the Lightspeed, with only one input it would never work for me.

So will someone please tell me why interconnects need to be under 2m.

Thanks
Tony
Cables of capacitance and you need a buffere or a TVC like your Bent (which I once owned)to drive cables with acculmulated capacitance. With your set up, the LSA won't work, it will become bandwidth limited, most noticeable in the bass. And the LSA is certainly not as convenient or flexible as your NOH - you are better of with what you have as long as you need to run those cables and need the connection flexibility you are already getting - but you are certainly enjoying the benefits of not having all the added complexity of a gain stage if you don't need gain. The BENT is an excellent preamp, so....