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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
georgehifi's avatar
georgehifi
10,312 posts
 
John47

That is unless you had your own wall wart, and just ordered the Lightspeed without wall wart, I had a few who've done this.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 


OK for US and Canadian owners of the Lightspeed Attenuator, I just did a search for definate linear wall warts that are all suitable.
First three are regulated, last two are unregulated, it does not really matter, so long as they are linear 9-12v with a 2.1mm plug that is center positive which they all are.
Or you can get the Teradac http://www.ab-system.hk/index.php?route=product/product&path=73&product_id=64 Cheers George

110-115v linear wall warts from Jameco, payment by COD, Paypal or Credit Card
All are suitable.

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_220898_-1


http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_1953639_-1


http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_162996_-1


http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_2192712_-1


http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_null_2197484_-1
john47
50 posts
 
Thanks for your comments George: no I didn't have a wall wart, I would have bought the package, so can about guarantee mine is a 'George' psu.

Banquo
"John47: did replacing the rca's make an appreciable difference?"
I would like to say yes, but being semi ancient and not keeping notes I don't remember. It was some time ago, but can say that my system sound has gone incrementally forward (over time). If there was no difference, or worse, assuredly I would have a big mental red alert.
Of note - I've used Nextgen Ag throughout, to match my silver ICs, and that I discovered (by removing) gold plating adds warmth, ie colouration I don't want. Expensive, but a oncer. Best RCA? I cann't say, but I read heaps before I bought.
Further: WBT Nextgen are not a direct replacement in the LSA, the mounting holes need enlarging, not straight forward.
Sorry if above seems like a non answer, but I don't recall, even subliminally, thinking I should restore the original RCAs.
Ag insider logo xs@2x
banquo363
371 posts
 
John47: you must have the most heavily modded LSA in existence. It would be interesting to a/b it with a stock version.
b_limo's avatar
b_limo
2,274 posts
 
Off Topic but I wanted to say I switched from a Classe CA-150 amp to a Prima Luna Prologue 5 lastnight and the lightspeed works great on both. No problem whatsoever with using the lightspeed with the Prima Luna; it sounds great! I secretly thank George everytime I fire up my rig. His piece is one of about four that changed my rig from mid-fi to hi-fi.
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