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
fiddler
581 posts
 
This thread was way more fun before you guys all turned into pantywaists!
clio09
3,353 posts
 
Well that first one of mine turned into three and the rest was history.

Going to be a real busy week working two rooms at THE SHOW. The Concert Fidelity, Electra-Print, and Atma-Sphere rooms are in a little triangular area (the first to are the ones I'm working), so it's going to be fun hanging out with all those guys. Too bad I'm probably not going to have time to go over to the Venetian.

Hopefully you'll not be speaking in tongues by the time I get back.
marqmike
839 posts
 
I want to chime in. I deal with color in differnt aspects of my business. I don't know if anybody is familiar with the gray scale? Color is measured, but not perfectly, by three primary qualities. Shade, intensity, and depth. The varieties are infinite as far as our eyes are concerned. Musical sounds are very similar, endless varieties. I think where it went wrong for me was going to digital before it could start to produce the endless varieties of sound that analog can. To me digital is better but it is still struggling. Sound systems I have heard over the last +40 yrs, many giving hours of listening, some with good tone, seem to be to restricted to way fewer different sounds than what I like and can achive. For instance I play the guitar, and when I go look at a new guitar I can look at 2 guitars or more, the same guitar, same brand, same model, same person putting it together, same close time of build, same wood from the same batch of wood(same tree and place on tree), everything possible the same and they all always sound different, quite a bit different. Most audiophiles I know (but there are a few that can) cannot hear a difference between such very similar guitars let alone 2 different but similar styled ones. I like to hear what the musician does with his paticular guitar because he may have 10 guitars but he uses the one he is playing specifically for that sound he wamts to achive. That is lost on a lot of sound systems that I have listen to. The same is true of other musicians and their instruments. And I cannot hear the variety of tones in many sound systems that people love and say it sounds like music. I don't deny it is music to their ears, it sounds good and it is musical. But it short changes the colors of sound that I like to hear. That is where I hear the biggest difference between passives and actives. From my experience even though you do get pleasant 'natural type' sounds from tube equipment(not all but most) it sounds very similar with all its tones and the result is very few colors of sound to me. It does do other things that make listening pleasant such as space, air, adds a bit of continuity or flow a tiny bit like analog off a LP. Solid state has it plus' and minus'. I like the LSA because it gives more variety of color to the music being played. But I do respect everyone elses tastes for themselves. Hope this doesn't confuse anybody but actually helps.
fiddler
581 posts
 
"That is lost on a lot of sound systems that I have listen to."

"I don't deny it is music to their ears, it sounds good and it is musical. But it short changes the colors of sound that I like to hear. That is where I hear the biggest difference between passives and actives."

I think that is what those of us who prefer the LSA to our actives have been trying to say. For us, the music sounds "for what we believe to be" more true to the actual source. (SOURCE being defined as the actual medium we spin vs. SOURCE being defined as what happened in the studio.) We have no control over what happened in the studio, therefore, that discussion is a non-starter for me. I can't change a single decision made during the recording process. I can only try to extract the information from the recording as accurately as my equipment will let me and change the sound of it to the degree that I want to KNOWINGLY change it.

I have tubes in my system. However, I do understand what they do to the sound; how they change it. That's what tube-rolling is all about. I don't try to kid myself. I can change the sound of my system with just two tubes and I am sure you guys can too. That's why I don't understand the debate about actives (tubes) versus passives as far as which one is more true to the source.

There is no debate in my mind that adding more and more caps, resistors, wire, tubes, etc. change the sound. The addition of more or different parts may make the music sound more appealing, but those same additions will never be as true to the source as a straight wire or as close to a straight wire as we can get. Parts have sounds.

After modding some of my own equipment it is abundantly clear what a difference parts make. No need to talk about caps, wire, tubes, interstage transformers, output transformers, etc. Simply swap out a cheap Alps pot with a DACT attenuator and hear the difference. And that's a difference of simple resistors!

For me, the LSA is much closer to a straight wire than my active. I can clearly hear more subtle differences with the LSA whereas my active lends a slight sameness to the sound depending on which tubes I am using (which by the way is the joy AND frustration of tube-rolling.)

If you have a Lightspeed, open it up. Then open your active. See which one is closer to a straight wire. You already know the answer. It's not even close :)
knghifi
1,668 posts
 
Fiddler

If you have a Lightspeed, open it up. Then open your active. See which one is closer to a straight wire. You already know the answer. It's not even close :)

Is LSA the only component in your system? What if the total parts count in a system (speakers, amp, IC ...) with an active is less then one with the LSA, is it always superior? Design, synergy between the components, quality of components ... there are many many factors.

LSA is not an empty box and has parts so it too has a sonic character.
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