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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
jult52
155 posts
 
I want to add my very positive initial experience with the Lightspeed here. After receiving some good advice on amp input voltage here, I purchased and plugged in the LSA into my system about a month ago and am very impressed with it in terms of:

1) detail - every recording I listen to now has added lines, inflections and colors;

2) color - the diversity of sound colors I now hear is maybe the biggest single change I've experienced. I listened to Philippe Herreweghe's sonically-excellent recording of the Mozart c-minor serenade for 8 wind instruments soon after getting the LSA. It was like listening to a kaleidoscope of timbres, with each of the instruments differentiated by register, type of attack and dynamic. Amazing.

3) musicality - this is maybe the most surprising effect, for which I was totally unprepared. The performers actually seem to be more "human". There's also a "spaciousness in time", in that the melodic lines "breathe" more (boy, is writing about music hard). My working hypothesis is that this is a result of the added detail: one can now hear more of the inflections given to the notes, especially during the initial attack, and this decrease in blurring at the transient edges of sound adds ease and expressivity to the music.

So I want to thank George, Pubul and Clio for turning me onto a component that is the end-state for my system (off the merry-go-round!). A few technical comments:

1) With my 1.8v DAC feeding my 2.1v input amp, I find most of my listening to be in the 12-2 o'clock range.
2) I swear there was some break-in in the bass with the LSA, lasting maybe 5 hours.
3) I am a newbie compared to the very experienced audiophiles here. I think suggesting a DAC/passive preamp/high impedance amp combo is a must whenever recommending a path forward for a newbie or someone with a less expensive system. I have a combined $2.5k sunk into my components between transport and speakers (ex-cables) and I think I'm done. Beat that price/performance ratio!

System: Transport -> Nixon TD-2 DAC with added power supply -> LSA -> W4S ST-500 -> framed Maggie MMGs.
The LSA replaced a modded Forte F-40 ss preamp which I think is very musical but which I now believes is grainy (not its rep).
pubul57 OP
3,712 posts
 
Jult52, glad the LSA worked for you, no audionervosa with this piece:) I think Clio and I have been recommending the LSA/Music Reference RM10 combo for world class sound for the cost of some folks speaker cables. If 35 watts is enough power, this is an awfully good example of great sound the real thoughtful engineering. You got yourself a very nice system there.
pubul57 OP
3,712 posts
 
"great sound from real thoughtful engineering..."
georgehifi's avatar
georgehifi
10,312 posts
 

Jult52
1) With my 1.8v DAC feeding my 2.1v input amp, I find most of my listening to be in the 12-2 o'clock range.
2) I swear there was some break-in in the bass with the LSA, lasting maybe 5 hours.
3) I am a newbie compared to the very experienced audiophiles here. I think suggesting a DAC/passive preamp/high impedance amp combo is a must whenever recommending a path forward for a newbie or someone with a less expensive system. I have a combined $2.5k sunk into my components between transport and speakers (ex-cables) and I think I'm done. Beat that price/performance ratio!
Jult52

1: At 1.8k your dac does not reach the 2v Redbook CD standard, if it did then your volume on the Lightspeed Attenuator would be around 11 o'clock, but there is no problem with where it is on your system at 12-2 o'clock.
2: I don't have an answer to this, but maybe you just got used to now having bass that is tighter and goes down to 0hz (dc) instead of what you were using for a pre before.
3: Yes the Lightspeed Attenuator represents great dollar value as seen in the latest recommended components in the April issue of Stereophile, as the $25,000.00 Dartzeel NHB-18ns preamp uses a Lightspeed Attenuator volume control with a lot of switching facilities and a lot of glitz.

Cheers George
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banquo363
371 posts
 
I have a combined $2.5k sunk into my components between transport and speakers (ex-cables) and I think I'm done. Beat that price/performance ratio!

I accept the challenge: Allnic h1200 phono stage>LSA>Music Reference rm10, bought for total $2550 (used of course, except the LSA). I must admit that an itch has emerged for a new phono stage, but the LSA stays put--perhaps forever.
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