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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
agear
1,362 posts
 
09-21-14: Georgelofi
Maybe then for those people they should be using 100 band parametric equalizers, but then that's just adding even more electronics with their associated colourations and distortions.
And then instead of hearing the music in it's "naked glory" we are hearing sterilized distortion infused approximation.

That would be a redundant gesture as much of the manipulation has already been done for you....:\

09-21-14: Georgelofi
I know Grannyring you and Agear love your $6K TRL dude active preamp full of massive coupling capacitors that the signal has to pass through. As you both have come on strong about it very early in this thread once before.

I don't own a Dude anymore (Viva Solista integrated) so no premeditation or subconscious agenda here. I just don't agree with you.

It seems there is a bit of a dude vendetta surge happening again. The late Pubul57 who started this thread warned me with an disturbing eyebrow raising email he sent to me a about you guys before he passed away RIP Paul.

I tangled with Paul on this and other threads, but he always handled himself with intelligence and philosophical grace. RIP.
lacee
811 posts
 
I am enjoying the recent discourse and thought I'd add something.
Years ago I had a very decent system,Acoustat model 3 with medallion transformer,Conrad Johnson MV75A-1 and Conrad Premier two pre.Cd wasn't around yet, so I listened to an Oracle TT, Fidelity research arm and Cart and a Verion MC Step up and a Janus sub.
One recording I enjoyed was the Dafos lp,especially the jungle track.

I have never heard more depth since from any other systems I've assembled, perhaps I should have stopped then.

Now I am using 3 panel Acoustat X monitors with their servo charged tube amps(modded)the LSA and an SME 10,V, and clearaudio combo into a Manley steelhead.
I miss that "illusion" of depth from days gone by, but I enjoy the clarity and preciseness of what I'm hearing now.

So,I would agree that some pieces of gear can alter how the music is reproduced in our homes, but none of us know just what the correct version is.

Was that illusion of depth due to distortions or phase shifts in the Premier Two that are absent in the LSA?

Of course not a fair comparison, there are too many other differences between the two systems to say that it was all preamp dependant.

Getting to the point, it's obvious to us all that everything is an illusion and it's all about trade-offs and what appeals to one person may not to another.

As someone said, that's why there's vanilla and chocolate.
And that's why some swear allegiance to tubes and some to solid state.

I've been fooled more than once into thinking I had gotten my sound to be "as good as it gets" only to be pleasantly surpriced when a new device or tweak proved that statement wrong.

Then again, has anyone ever really heard it "as good as it gets"?

I don't think so, and I doubt anyone ever will.

I enjoy the effortless clarity that the LSA brings to the table.

For me it's like a more direct link to the music,almost as if it's not even there in the mix of gear.

It may lack some of the sonic fireworks I and others have come to expect from audio gear, but then again, who knows what is and isn't the best reproduced sound?

Until the audio community can agree on a benchmark set of parameters other than specs for specs sake,all things will be all things to all men.
canekong
1 posts
 
I have to say after connecting it my Berning ZH270 it has a lot of Wow factor to it.  First thing you notice is the huge soundstage.  The Berning and the lightspeed are a match made in heaven.  The Berning needs a better attenuator and the lightspeed brings it big time in dynamics, bass and most importantly for me is control.  My Tannoy Golds are playing like everything that I have read about them and their ability to produce beautiful music.  I am presently awaiting the capacitor upgrade I did on the phono section that I have and will let you know then what I think.  I primarily listen to vinyl but have been streaming music via Sonos and Spotify.  If the music sounds this good then I can't wait to get my phono back and listen to it then.  I never thought the volume control could impact the sound that much but I was completely wrong!!! 
Thanks,

Van
roymail
10 posts
 
Can someone explain the advantage of leaving the LSA turned on 24/7 with the knob at 12:00? I recall reading somewhere that this is what George recommends. It may have something to do with the longevity of the octocouplers.
georgehifi's avatar
georgehifi
10,312 posts
 
Hi Roy. Sorry about the delay in answering, I've been busy making them.

There is no advantage in leaving it on 24/7, in fact if it is not used for a while, I "suggest" it be de-powered. As I've only had a couple out of the close to 1000 units made returned that were taken out along with other components in the system due to spikes from storms, lightening strike or brownouts etc..

If it is left on and not used, I do "suggest" that the volume be left at the mid position, as it halves the led (not the ldr) brightness of the series and shunt led’s.
Because if it is at minimum or full, the shunt or series led will be at just below it's maximum full brightness, even though it is said that an led last for tens of years at full brightness.

As for your email regarding if a used genuine Lightspeed Attenuator your looking at is a MkI or Mk11, it can be only a MkII, as all genuine Lightspeed MkI's manufactured earlier were converted to MkII status. There are only clones of the Lightspeed that can be MkI or do not have quad matched sets of led/ldr's.

Cheers George
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