2. amps-preamps
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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
teajay
1,702 posts
 
Hi Paul,

To answer your question regarding why in my system an active preamp sonicly out performs any of the passives I have owned or auditioned is based on either the gain or buffering they offer: Don't have the foggist notion why from a technological perspective.

In my circle of listening friends four of us have all had some of the highest regarded passives in our systems and enjoyed what they have to offer, hell I wrote a rave review on the Bent Tap here on the GON, yet something was found missing after awhile in our systems when using a passive.

In my system it seemed that the jump factor or how alive the music sounded was lost to a noticable degree. Also my sound stage was not as deep and individual players were not as 3d with air around them when compared to using an active linestage. Finally, timbres sounded less natural to me with the passives then with my tube based actives. Sonicly, my favorite passive still is John Chapman's TAP because it came closer to not having these shortcomings compared to other passives.

Why this so from a technological angle, I don't know, you and the other guys seem fascinated to try to explain it in objective terms. I really don't care why I just know what sounds more like real music and that's what really matters to me.
fiddler
581 posts
 
Teajay,

Your constant haranguing of George is clearly a veiled attempt to stifle and build consensus against what you don't like about George's posts, otherwise you wouldn't be here wasting everyone's time.

"Being the arrogant bastard that I am..."

Well - finally you offered something worth reading.
pubul57 OP
3,712 posts
 
Terry, what is interesting is the Placette Active that we both used obviously is about as good as it gets on the buffering side - essentially capable of being driven by any source and driving any amp an IC - I too found the Placette and BENT (I used the AVC version) sounded fantastic. Then you discovered the German linestage I can't remember and now the Concert Fidelity after having auditoned many of the finest linesstage in the world. What I always wondered was of our slightly differetn conclusions regarding our preference is due to the fact that I have always used tube amps and you have been using SS (Pass & Threshold?). I can't prove it, but I think you like what tubes do to the signal and it is simply not there for you with a passive - fine as it might sound.

As to your earlier comment about not following the DIY forums, I do think you view of George and where he is coming from would be different if you followed that thread over the past 5 years - I think you would have a better sense of him and I think Clio9 (Anthony)alluded to a possible misperception. I suspect we would all enjoy a fine brew after some heated discussion....
clio09
3,360 posts
 
Sipping a martini right now in First Class. Life's looking good at 30k feet.
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banquo363
371 posts
 
Teajay: I see you own the Concert Fidelity preamp. I heard it at last year's THE Show in the room where Clio09 was working. Amazing sound. If I could only locate the $20k I misplaced, I'd happily replace my LSA with it.

I just read Arthur Salvatore's review of the Coincident Statement Line Stage. He mentions the LSA as a possible player in the best preamps sweepstakes (although he hasn't tried it himself). He mentions it despite advising against all resistor based passives--the LSA is one of those, right?

Unlike the CF, the Coincident is within reach (for me) and is tempting because I know my phono stage has a higher output impedance than is ideal for the LSA. It nevertheless sounds superb and I don't know if I'm missing out on anything, but one always wonders. Too bad their phono stage has too much gain for MM carts.
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