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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
 
Agear hi your questions to me are answered here it's a big read, I started doing these some 30 years ago it was new then, I should have patent it, it is refined sonically to the max today, without being overly complex, and pricing kept low as possible.

http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp.html

www.lightspeedattenuator.com

Cheers George



agear
1,362 posts
 
Pubul57, I like the concept of blinded sessions to remove bias. It is quasi-scientific. I think a lot of manufacturers are sensitive to the whole shootout model (blinded or not) since a poorly executed setup can talk the results and hurt their business. I am aware that most hi end audio companies in the US are mom & pop outfits, and the last thing I want to do is damage their livelihood. That being said, my pre-amp maker (TRL Dude) was stoked about the idea.

I think a second issue is pride. A lot of philes are wedded to their gear and get tribal on you fast (myself included) when challenged. At this point, I don't care about looking like a rube. If something is better, its better. The truth sets you free at the end of the day.

Prior to owning a Dude, I experimented at the level of the pre-amp quite a bit. My Wifi front end has enough juice to easily drive amps directly. I liked the sense of clarity, but the soundstage was always too flat for me. It did not sound right. In my previous rig, I used a Granite Audio 657 tubed CDP without a pre-amp. It had an enormous amount of gain in the output stage, and my system always sounded more dynamic and alive without a pre-amp. This was an experience shared by a majority of 657 owners. Conceptually, it harkened back to the 80s/90s when a straight wire with gain was thought to be optimal (by some).

Bringing things into the present tense, I discovered the TRL Dude (thanks Bill/Grannyring). It had the dynamics and sense of control of the 657 with with so much more. That being said, I am always open to hearing "more." TVAD mentioned his new VRE-1 as being a passive "with balls" and how much he is in love with that device. I did not realize that the Concert Fidelity pre was a "passive with balls" also. Dale Pitcher from Intuitive Design is using that pre at RMAF this year. I own some of his equipment and respect his ears. That being said, a buddy of mine who owns a highly modded but vintage TRL GT3 pre-amp (15 years + I believe) recently demoed both the Concert Fidelity and Lightspeed and still preferred the TRL pre. In particular, he said the LS lacked "dynamics and control."

Pubul57, out of curiosity, what pre-amps have you compared this device to? Atma-sphere per chance? Have you ever hear it with solid state amps? What is your source? It does seem as if you need fairly specific conditions for the LS to thrive.

As an FYI, I used to be a Merlin owner. Loved those speakers. Was about to purchase the ARS Filharmonia and got sucked down another rabbit hole audiophile style....
pubul57 OP
3,712 posts
 
Owned the Ars Sonum (twice:)) Most recently I have owned CAT SL1 Ultimate, Lamm LL2, ARC LS25, Dodd Battery, Joule LA 150MKII Signature Edition, Placette Active Linestage and RVC, K&K TVC, and the BENT TAP AVC. Of that batch, the Joule was my favourite, but sold it after a month or so with the LSA, just did not make sense to me to keep it, in my system with an EMM Labs front end (switchable 2v and 3.6v output), the LSA played on par or better to those, though I only had the Joule at the same time. I never compared it with the Atma preamp I own becuase I use it exclusively with the Atma-amps. The LSA is used with my single ended Music Reference amps. If I were to make a sane recommendation for Merlin owners, it would be to get the Ars Sonum, and "stop worrying about it":) Not that is was the best, but it is good enough to get off the equipment merry-go-round.
clio09
3,364 posts
 
I like the idea of blind listening sessions, why are so many audiophiles and reviewers against it, or at least to believe in it as a effective method for assessment? That always seemed odd to me. Yes, it would be a good idea to do such a test absent the knowledge of when one is listening to a particular piece, especially when they have invested themselves in a piece financially and/or emotionally.

Most of these tests as conducted today are flawed to some extent. Unfortunately you can't create an accurate enough control environment. That being said I think they are fun and a method by which opinions can be shared and discussed. Not that we're going to get any definitive answers, more likely the usual subjective opinions.

One thing that would be nice in the LSA, and most modern preamps, though it might "ruinous" or a least "deleterious", is a scheme for balance control to account for recording mixes, room geometry, and human frailty as we age - not sure how many ears are balanced L/R- perhaps than we would like.

Mine technically has a balance control by virtue of it's dual volume controls. I like this feature for all the reasons mentioned above.
pubul57 OP
3,712 posts
 
I should have thought about that, take that over remote cotrol any day.
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