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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
 
Dual L&R controls in every PDF broucher I send out, is the only option I do. It's a $30usd option, but I tell everyone who inquires about it they are not as user friendly as the single stereo pot. As for different cd level volume change, you have to get the balance right again.

Cheers George

catastrofe
87 posts
 
My LSA is on it's way. I'll be comparing it to my NAT Symmetrical and will post my observations/opinions.
pubul57 OP
3,712 posts
 
That is quite a nice write up on the NAT on 6moons - it would be very interesting to hear your opinions of such a "robust" and expensive preamp up against the "simple" LSA.
marqmike
843 posts
 
I have had my LSA for about 3 weeks. George is great to deal with by the way. However my LSA is even better to deal with. I hope it doesn't have any longeity issues it is that good. Many people will mention specs, design superiorities or faults, and other reasons to make excuses for their equipment. George does not. In fact George is not positive(he thinks he knows)even why it sounds so good compared to other passives-actives and whatever in the right system. I for one find that honesty refreshing. But the proof is in the sound or listening. In my system the sound becomes a lot more colorful steeped in more accuracy of the natural tones and timing of real music. As a play around guitar player and a 35 year audiophile I hear way more of the real tags of music in persnickity audiophile terms. Equipment I have used is Jeff Rowland Consumate, Audio Research LS1, Forte 40, Sumo Athena passive/active. I don't know what could be this good. Just some old timey input. Keep up the good info on this line.
clio09
3,360 posts
 
In my system the sound becomes a lot more colorful steeped in more accuracy of the natural tones and timing of real music.

Marqmike, glad you're happy with the LSA. I think you really hit on something with this comment. It pretty much describes how I feel about the LSA and IMO it's more evident now that I use it with a battery power supply. While the term "colorful" would not be one I would have thought of using and IMO traditionally goes against how I would describe the sound of a well designed passive, nonetheless I think it makes a lot of sense.

To put it another way, I think we sometimes get caught up in how our equipment performs on a linear level. I know I have been guilty of such. Focusing way too much on frequency response, imaging, sound staging, etc. Since I purchased my Audiokinesis Jazz Modules a couple years back they really started opening my ears up to things like natural timbre and timing. Things you could consider colorful versus linear IMO. In fact, the designer of my speakers had his priorities set so that reproduction of natural timbre was a high (if not the highest) priority in his design. He never set out to build a speaker that sound stages well. It wasn't nearly as high a priority. Now you might think that speakers designed in this manner add a fair amount of coloration to the sound. Well most who have heard them, including some well respected experts say they are the least colored horn designs (actually wave guide) out there. I think George may have achieved something similar in his design approach with the LSA. Something pure and true to the source, yet doesn't lose that ability to convey natural timbre and timing.

Pubul57 always stresses the importance of system matching with passive preamp designs. I made note in another thread I started as to how creating system synergy with a passive preamp could be one of the hardest things to achieve. Potentially too many variables to satisfy. However, if you can satisfy the variables, then the design of the passive becomes paramount to achieving what we experience from the sound.

I was just reading something where the following quote popped up:

"I am not so much interested in where the musicians are on the stage, as in why they are on the stage".

In my system the LSA enhances that train of thought for me.
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