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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
b_limo's avatar
b_limo
2,273 posts
 
This thread has had 18 million views... that is nuts.

I had a lightspeed years ago.  Should have never sold it.  They are the best preamp for the $ no doubt.  It really does just get out of the way of the signal.  You do need proper gain matching but if you have that, a good dac and a good amp, the lightspeed is just awesome.  
georgehifi's avatar
georgehifi
10,312 posts
 
This thread has had 18 million views... that is nuts.
Yeah Bruce, and the amount of PM’s are even more nutz to reply to.

Should have never sold it. They are the best preamp for the $ no doubt. It really does just get out of the way of the signal.
They pop up used sometimes for around $200-300usd there are over 950 units out there all over the world, just email me if you decide to get one of them for the correct wall wart for the US. And thanks for that rap!

Or if your electronically minded, you could make your own, that I show how to do here. 
https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp.html

Cheers George
zeusodin's avatar
zeusodin
17 posts
 
Let me start by saying that I have read every post in this gargantuan thread. Every. Single. Post. I agree, the LightSpeed Attenuator is a mandatory component of any audiophile-level sound system. I love mine so much that I might attempt to build @georgehifi's DIY instructions. And this from someone who has two left hands. I want to see a bit of what George saw when he envisioned this masterpiece. Of course, get the dual volume version. It's the only version I considered.

The speakers in my system are Canton Reference 3.2 DC. For the life of me I couldn't figure out why these speakers were so undervalued. These 110 lb behemoths when powered properly with decent room acoustics give a sound of true unadulterated bliss.

I decided to go with the discontinued Classe CT-M600 monoblocks. I read a number of reviews but it was Audiogon user caphill who wrote: "Dynamic headroom and bottom end extension and control are excellent. The Classe CAM 600 excels in extracting musical details and nuances and information. The tonal is neutral and balanced across the entire spectrum with a touch of warmth. The noise floor is one of the quietest I’ve heard from any high end amplifiers. The amps are dead quiet and the music emerges from a dark black silent backgrounds." Enough said.

But it is the invaluable LightSpeed Attenuator that ties all this together. When purchasing the new pieces for my system, it was the LSA that I purchased *FIRST*. Sight-unseen, untested, and unheard based on reviews from Audiogon. The LSA gives you the feeling that you are listening to the voice of God. The sound is so enjoyable so ethereal. The LSA simply gets out of the way of the music and passes on exactly what is on the recording. Few if any products actually accomplish this. I just don't have the words to properly convey how I feel about this setup helmed by the LSA. It goes without saying that georgehifi is a genius. And a very kind and generous soul who could have easily sold his invention for 10-100x the almost insignificant price he is charging. Thank you so much, George! The LSA is a priceless creation that everyone should hear and own.
georgehifi's avatar
georgehifi
10,312 posts
 
 
zeusodin
The LSA gives you the feeling that you are listening to the voice of God. The sound is so enjoyable so ethereal. The LSA simply gets out of the way of the music and passes on exactly what is on the recording.

Thanks for the great Lightspeed rap and kind words zeusodin, if you want to experiment a little it's only a slight improvement over the linear regulated supply the Lightspeed has already to control all the LED's brightness.
And that is to power them using this 12vdc CCTV Li-Ion rechargeable battery setup, cheap enough for the slight improvement. Just make sure with the seller that it's 12vdc and that the dc plug that goes into the Lightspeed is 2.1mm X 5.5mm and HAS to be positive centre.
 https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2540003.m570.l1313&_nkw=12v+cctv+lithium+...

BTW all, I've halted all OS orders for a while as the last one took nearly 3mts to get to it's destination, the postal service all over the world is shot to hell, I'm also finding parts getting to me are taking twice as long.

Cheers George 
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