2. amps-preamps
  3. 1276356977

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
 
09-19-14: Georgelofi
It all starts with the source, in your equipment.
It sounds very good to me, and I have no wish to change it's sound or colour it in any way.

Cheers George


When I hear "source," I think source material. Do "we" really want to hear all our poorly recorded and mastered music in their naked glory? I think that is one reason why people spend so much time and energy fiddling with dacs and pre-amps.
georgehifi's avatar
georgehifi
10,312 posts
 
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.
grannyring's avatar
grannyring
6,436 posts
 
George as I have shared with you in the past I respect you and your passion. While I do think you can be tad narrow in your view of other ways to attain fidelity, I nevertheless enjoy your helping spirit and enthusiasm.

I would love Mr. Pass to share with us if he thinks his expensive and wonderful active line stages sound better to him compared to a passive like the LSA. Would he say your passive is as good or better sounding? Forget features, as I am just talking about sound quality and how live and real it sounds. I think he would say his best actives sound more like the real thing if asked this direct question. Love to hear his comment on this one comparison question.

I know there is technically no need for an active as passives like yours can sound good indeed. Seems the very best attempts at SOTA music within a stereo system often times involve great actives...not always.

What about the recording engineers of the world? Should they be eliminating gain stages? Fact is eliminating these gain stages does impact dynamics. High frequencies compress all together so you can hear everything at the same level. The background noise is just as loud as the voice etc...This is just an example of properly executed gain stages and their importance.

My experience is not one proving my tube active colors the sound to my taste. You have said this often, but that is simply not the case George. For me, and based on my experience with with TRL Dude compared to the LSA, color had little to do with it.

The dynamic impact of whole performance and individual part becomes more live and real sounding with the Dude. The relative volume, layering, placement, impact, of each instrument to the other on the stage are captured with greater fidelity with the Dude. These are not subjective color preferences, rather they are the nuances that make a stereo system sound like real, live music.

I don't point this out to somehow prove my active is better than the LSA for all, but in an effort to have a broader discourse on the different roads to fidelity to the music. No absolutes and an open mind on other possibilities.
georgehifi's avatar
georgehifi
10,312 posts
 
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.

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.

As for Nelson Pass's thoughts on passive preamps, I present to you once again, his quote on the subject in case you missed it before..

Nelson Pass, "We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."

Cheers George
grannyring's avatar
grannyring
6,436 posts
 
Your Dude comment is strange and out of place. Sorry to see it and sorry you just will not have a nice and reasonable conversation and back and forth.

My feelings and passion for audio go far beyond the box you placed me in. This is also true of others you commented on. Read all I review and post about. Most disappointing George.
More to discover