2. amps-preamps
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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
vyokyong
23 posts
 
Hi,

I just modded Light speed attenuator by replacing stock RCA jack with WBT 0210-Ag RCA "Next Gen" Pure Silver in signal path, Female Jack. I have modded my Zen Mystery Amp by replacing stock RCA jack with WBT 0210-Ag (Ms - metal nut) RCA "Next Gen" Pure Silver in signal path, Female Jack. And sonic improvement is huge in term of transparency, transient and micro-details. Then I want Light Speed Attenuator to be modded same thing.

This is instruction from George of how to replacing stock RCA jacks.

below are the opening instruction, if you change the rca’s they must be full bodied metal, as they have to have electrical contact from their body (which is earth) to the Lightspeed chassis on all 4 rca’s.

1: Remove two only top screws at the back
2: remove all 4 screws at the front.
3: Pull out front panel and bezel only about 10mm and lower.
4: Slide top plate out from the front.

But the RCA jack WBT Next Gen Silver 0210-Ag body is plastic, not metal. So that they cannot be ground through chassis contacting point at cut whole bare metal. Then I use silver wire to connect all ground point of RCA jack of both in put RCAs and out put RCAs and ground to chassis at one point only.

Result is that my Hi Fi system can play louder than before. It may be 1-2 dB or easily to hear different loud. Second both hi and low frequency is more extend with better dynamics contrast. The improvement is dramatic better and it is worth every penny to replace stock RCA by WBT RCA jack of pure silver in signal path.

However I think that using direct wire to connect between ground or negative points of both in put RCAs and out put RCAs together has affected better sonic improvement. (instead of using back panel aluminum plate as ground path). The Light speed attenuator owner can do simple modification of Light speed attenuator by using good quality wire to connect all RCAs ground together to improve the sound quality.

Hope this information will be helpful.
marqmike
676 posts
 
Thanks for the heads up on that Vyokong. Give us some more impressions after you have had them a couple of months. Thanks again.
vyokyong
23 posts
 
Thanks Marqmike,

Yes, I will.
banquo363
371 posts
 
Hope this information will be helpful.

Yes, very, Vyokyong. And motivating as well. I've been meaning to do this for quite awhile--now is the time?
vyokyong
23 posts
 
Hi,

I want to add that I replace stock wires in signal path with Duelund silver hook up 2 wires. Just make sharp point of Duelund silver hook up 2 wires and solder it to PCB board.

It improves Light Speed Attenuator's sound to next level in term of transparency, 3D image and speed (PRaT).

I hope that George will think of launching Light Speed Attenuator Signature model with high quality parts (all pure silver wires and connectors in signal path) and premium luxury chassis to capture another audiophile segment. Because this audiophile segment have a lot money and just sound quality of equipment from luxury chassis. I bet that Light Speed Attenuator can challenge many top brand preamp if using in system with no problem of misimpedance matching and no problem of gain.
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