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
Thanks for the tips George, but with the TeraDak my wallwart days are over.
I don't care if my wallwart was linear or smp,What this does is amazing.You need to try one.

It cost me $60.00 Canadian, so yes I am from the Northern half of North America.

I've done some more listening and any edge that I felt was there has not shown up,but I should revisit the Graceland lp just to check and see if the sibilance is still there.
But my enjoyment with the pairing of the TeraDak/LSA is making me reluctant to go back to what I've just played.All I want to do is move on to the rest of my library and discover the pleasures anew.

The TerDak makes the LSA spring to life,it's like steroids for the LSA.

It's too bad anyone who has used the LSA with a wallwart, linear or not,and moved on didn't know about the TerDak alternative.They missed out on how good the LSA can sound when given a decent source of power.

For those who are thinking about adding a TerDak,don't scrimp on a cheap power cord just because this thing costs 60 bucks.
Perhaps my power cord is making more of what the TeraDak is doing for the lSA than a stock power cord would do.
As I've said I'm perfectly happy with the pairing and not the least bit ashamed using a power cord that cost almost 4 times what the LSA/TeraDak combo costs.

It's all about what works that matters to me,so call me insane, I won't mind because I am insanely happy with the sound improvements I've made to my system.

My old walwart cost about 25 bucks, no shipping, I bought it at a computer store.
Saving a few dollars and foresaking what the Teradak does isn't sane in my book.

Those saved dollars only waste thousands of dollars invested in music and gear when the system is compromised,which I feel any wallwart will be guilty of.
How is my battery pack comparing to these wal warts? I went with the battery pack because I thought it was better...

I'd prefer not to go to the teradak simply because the battery pack looks cleaner and I don't have to buy another powercord and I only have 2 components plugged into my ps audio quintet in different banks.

If the teradack is going to be an improvement over the battery pack, well of course I'll buy it, but it seems like you guys are comparing the teradack to the worst power supply (smp is the worst one, right?) and not the linear one. I read some comparisons between the linear power supply vs. the battery pack, and the battery pack supposedly sounded better...
I believe the Teradac power supply (http://www.ab-system.hk/index.php?route=product/product&path=73&product_id=64 ) is a great linear power supply. And at a good price.

But from the Lightspeed owners in the US and Canada that have said it's far better than the wall wart, we really need to know if it was an SMP wall wart, they were comparing to. It is very hard to tell the difference visually between an SMP or Linear wall wart. The portable AM radio trick is the easiest way to tell.

Cheers George