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
Yep Clio09 your points on the high end builders are interesting. Your real life example with the Transcendent amp is a great example.

Ok, time to listen to Van the Man with my microphonic tubes:-) Van's voice seemed you ring more when he was younger. He now has a warmer, mumbling tone that is more microphonic tube friendly.

I will try George's tube test soon.
I will try George's tube test soon.
Grannyring

It's not my tube test, it's a well known way of checking for microphonic tubes out in the field among techs without the use of expensive equiptment. You can aslo do the same with tubes in poweramps, not just pre's.

Cheers George
Knghfli - no, I kept the Atma-sphere preamp, ideal match with their amps. The only reason I mention those other linestages is because there is something to be said for the context of what I am use to. Being enthusiastic for the LSA just would not be the same if I came to it from a $300 NAD preamp, of course I would be enthusiastic. But the point is the LSA is not just good for the money, but good to someone who has owned some very fine tube line stages; that does not mean that someone else will come to the same conclusion that I have regarding the LSA, and I'm sure that others might prefer the CAT, Joule, etc. and they great line stages indeed and I could easily live with any of them, but I still like trying different gear. I'm just trying to make the point that it is with line stages of that quality that the LSA should be compared with (and the Bent TAP AVC, K&K S&B TVC, Goldpoint, and the Placette which I have also owned), at least to audition it and see if it floats your boat.
Have enjoyed reading this thread from the very start, so here's my take on the Lightspeed Attenuator:

1) I and a follow group listners auditioned it in a very high end system and thought it was good but nothing earth shattering, I had shared this with Paul I believe with a voice mail or E-mail, that its sonic performance was not a significant or qualitative shift over the sonics of other great passives which I have used as references such as the Bent Tap TVC or the Placette buffered. I choose not to put the results of this auditioning experience on this thread for two reasons. I had a hunch it would be dismussed by some of the true believers in the Lightspeed because of this or that, impedence mismatch or something else, not fully broken in, which power supply, etc. Secondly, this is not Paul's position, well that's just your personnal taste anyways. Absolutely, personnal taste and system synergy is and will always be present. My system just does not offer the same illusion of real music with any passive including the Lightspeed compared with a reference tube based linestage.

2) It's the price dummy, it's the price! Yes, I totally agree with the permise that this piece offers tremendous valve for the money, even if it's no better then the above mentioned passives which I have used as references at different times in my system, it still costs thousands of dollars less! However, that does not mean, taking out the performance vs cost ratio, that it ranks as one of the world's great linestages because it stills lacks what great active tube linestages have to offer in my opinion. I have no worries regarding heat or tubes wearing out.

3) I have nothing but respect, trust, and kind feelings towards the man who started this thread, Paul, who writes extremely well and helps spread very interesting and useful information here on the GON. Happy new year Paul. However, if I did not know better, and I do, I would think that Paul is either George's private partner, owns lots of shares in George's company, or finally gets a piece of the action. Now none of this is true, please, I'm trying to make an attempt at humor and Paul, if you take what I just stated seriuosly, I apologize in advance. However, George should be very greatful, this thread at times comes across to me like an unpayed advertisement or a missionary message to Gon members to save us from ourself's regarding the slippery slope of performance vs cost ratio. I know it's a flaming bargain!, but how many times is it necessary to state this over and over again. It's makes perfact sense that George has an invested interest regarding his baby, I think him taking the time to help out on this thread with useful information regarding how to maximize your Lightspeed's performance is terrific, but please you have not invented the "sonic wheel", even though you offer a great product at a very reasonable price. I do totally accept that you have a position regarding what a linestage should offer sonicly in one's system, however your take, is no more right or wrong then my take or anyone's else's. It's personnal taste not an objective measure in the long run in this hobby. It just seems to me, and I understand why, George, is stating to come across as a salesman on this thread.

Well, that's my take on this marathon discussion, it's always fun to see what the next post will be, so I'll keep reading this thread, but I'm keeping my tube based linestage for now, even though it would be great to save so much money, but just don't like passives in my system any more, but the Lightspeed might be great for you in your system!
There is something to be said for those that have a conviction and stick by it. I have a lot of respect for what George did with the LSA because he has determined what he feels a preamp should accomplish, and while I agree that his way is no more right or wrong than anyone else, he has developed a product based on his conviction regardless of the fact he could have probably made more money developing active linestages had he chosen to go down that path.

Its like Ralph Karsten's approach and his conviction about using output transformers in amp circuits. He is in the minority among his peers (even though his research and papers do a great job explaining why his approach may be the better one), but he keeps plugging away at it when IMO it probably would have been easier for him to just design a circuit with output transformers and call it a day.

Lightspeed ahead...