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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
erwann
6 posts
 
My analog front end is a vintage Verdier driving a London Decca Reference cartridge on a Cartridge Man Air Bearing tonearm. With its 5 mv output the Decca is not exactly shy, so signal strength is not a concern with the LightSpeed .

I use the phono stage of a modded EL34 type Scott amp, which in terms of what I would consider absolute musical value, is without peer. The ability to further tap that value upstream via the REC OUT into the LightSpeed Attenuator is the equivalent of adding Bybee Golden Goddess 'Super Effect' Speaker Bullets, which to me, was a revelation, and is of the same order of magnitude as being able to bypass that dismal digital attenuator on my Oppo, whose potential has finally materialized.

For me, pace and tone are paramount, and trump imaging any time. Music is not about hollow graphic photography, but about living the performance. The Lightspeed clarifies intention and complex interdependence between notes the way a juggler keeps his balls, up in the air where they belong (sorry about that).

Insofar as the only weakness of the Lightspeed is the additional interconnects required, time permitting I hope to experiment with the diy version of the Tempo Electric Aurum Ag Hybrid interconnects, which should do justice to this exceptional little gem.
georgehifi's avatar
georgehifi
10,312 posts
 
Ewrann (Gerald), thank you very much for the kind words on how the Lightspeed performed with vinyl, and for rekindleing my memories for the Decca London cartridges, which on a great TT/arm such as you have, were one of the best sounds I could get from vinyl, the slam and dynamics still live with me today.

For those young bloods reading this, here are some similar pics of what Gerald's setup is for vinyl repaly.

http://www.tnt-audio.com/sorgenti/conductor_e.html

http://www.blackpearls-shop.de/DECCA-AEC-LONDON-REFERENCE-TONABNEHMER

https://www.flickr.com/photos/hannes_frick/7645363880/

Cheers George
erwann
6 posts
 
Hi George,

I don't use the Isolator cartridge/headshell de-coupler pictured at
http://www.blackpearls-shop.de/DECCA-AEC-LONDON-REFERENCE-TONABNEHMER

Instead, I couple the Decca to the arm and the arm to the 'table with Mapleshade's Nanomount System,
(http://shop.mapleshadestore.com/prodinfo.asp?number=NANOMOUNT).

Mapleshade's no-nonsense vibration control products shame anything else for a fraction of the price, which is exactly what you've managed to do. Its founder, Pierre Sprey, fathered the legendary A-10 Warthog, recently rescued from extinction by Congress. It's the only USAF aircraft designed solely for close air support capable of extended loitering over the battlefield, to devastating effect, again for a fraction of the price of an F-35. Have a look at this: http://www.motherjones.com/mojo/2012/01/a-10-f-35-air-force-budget.

Your LightSpeed is the stealth version A-10 of the audio battlefield. Simply devastating!
georgehifi's avatar
georgehifi
10,312 posts
 
Here is another reasonably priced linear powersupply, you Lightspeed owners may wish to play with, with digital readout!!
It has the correct size output plug, at 2.1mm X5.5mm with center positive.

All you have to do is specify 220v or 110v mains and say you want the output set for either 9vdc or 12vdc. Both voltages work, as I have a second regulated supply inside the Lightspeed which re-regulates again.

http://www.ebay.com/itm/Hifi-linear-power-DC-1-USB-amp-DAC-external-power-supply-with-digital-display-SN-/221458260575?pt=US_Home_Audio_Amplifiers_Preamps&hash=item338ff0e25f

Cheers George

richarddunn
1 posts
 
This only applies to UK and European Union members.

There seems to be complete ignorance about these Light Dependent Resistor products. A word of warning really needs to be published about LDR based pre-amps. LDRs contain Cadmium gas which is lethal (kidney or liver failure) if eaten or breathed and is a long term serious health (Cancer) risk if just touched on a regular basis. Because of this it is illegal to import or sell these items within the EU as they are not RoHS or WEEE approved, so cannot be given a CE mark. This is true for both kits and built products.
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