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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
rodolphecassis's avatar
rodolphecassis
4 posts
 

Hello, I have had a Light Speed for several years, connected to two Almarro A340 blocks or two JA30 blocks. After doing some research, it seems that it works best with the knob at 12 o'clock. Since I have Klipsch horns, it really rocks.

 

Under these conditions, it is very difficult to listen at a normal volume, so I decided to put a Goldpoint SA1 behind the LSA to reduce the volume. 

 

Is this a good idea? 

 

Translated with DeepL.com (free version)

Shrek symmetrizer > i7 fanless Roon2 Rock Qobuz Hi-res > tweaked Netgear + Meraki > Linq Aqua core HQPlayer > Aqua La voce S3 > Light speed attenuator > 2 Almarro A340 or Jadis JA 30 blocks > Klipschorn 1995 Eliptrack 400 ES400 ES 5800 The messhttps://i.ibb.co/zbmtsMG/caaefccf30ba.jpg

The room https://i.ibb.co/mBRbSfL/0f57377f723a.jpg

rodolphecassis's avatar
rodolphecassis
4 posts
 

Bonjour, je possède un Light Speed ​​depuis plusieurs années, connecté à deux blocs Almaro A340 ou deux blocs JA30. Après quelques recherches, il semble qu'il fonctionne au mieux avec le potentiomètre en position midi. Avec mes enceintes Klipsch, le son est vraiment excellent.

 

Dans ces conditions, il est très difficile d'écouter à un volume normal, j'ai donc décidé de placer un Goldpoint SA1 derrière le LSA pour réduire le volume. 

 

Est-ce une bonne idée ? 

 

Traduit avec DeepL.com (version gratuite)

Symétriseur Shrek > i7 sans ventilateur Roon2 Rock Qobuz Hi-res > Netgear + Meraki modifiés > Linq Aqua core HQPlayer > Aqua La voce S3 > Atténuateur Light Speed ​​> 2 blocs Almarro A340 ou Jadis JA 30 > Klipschorn 1995 Eliptrack 400 ES400 ES 5800 Le bazar https://i.ibb.co/zbmtsMG/caaefccf30ba.jpg

La chambre https://i.ibb.co/mBRbSfL/0f57377f723a.jpg

clio09
3,413 posts
 

Well if the sound is still pleasing to you in this arrangement then it's a good idea. However, it's not something I would do. It just introduces another component into the chain with more impedance matching implications. Try looking into ways to either reduce the gain of your source or amps.

rodolphecassis's avatar
rodolphecassis
4 posts
 

Merci pour votre réponse, effectivement un élément rajouté, mais réduire la source c'est utiliser le volume numérique de roon pas top, réduire le volume ampli impossible sur les 2 blocs jadis Ja 30 pas de bouton volume.

 

Thank you for your reply, indeed an added element, but reducing the source means using the digital volume of Roon which is not ideal, reducing the amp volume is impossible on the 2 Jadis Ja 30 blocks as there is no volume button.

clio09
3,413 posts
 

Why do you feel that the 12 o'clock position on the Lightspeed is best? The characteristics of its pot is similar to a 10k potentiometer. As long as you have a very low output impedance on your source and a high input impedance on your amps then you should be okay (assuming you use short cables) no matter the position of the pot. I use mine with a very sensitive amplifier (under 1 volt) and at the 10 o'clock position everything sounds fine. What is the value of the pot you have on the SA1.

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