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
 
"Fiddler, you are for some reason quite short with me in your remarks. No reason to be so strong with me..."

Wow, are you an overly-sensitive guy or what, Grannyring! Like I said earlier, "Quit your whining."

(BTW, if you haven't seen it, look for this commercial. "Ask your doctor, it may be as simple as Low T.")

You said, "You take these past posts and apply them to a current thread totally out of context."

Nonsense. Your quote from that past thread was in perfect context here. Go read the thread. You just don't like it because you got busted in your own words. "You took me out of context" is the last refuge of a desperate man.

"You seem to suggest I am not worthy of this topic and to stop having input on this thread." Nope...didn't suggest that anywhere. I simply said you are beating a dead horse and your argument flies in the face of conventional audio wisdom.

And if you feel I have been short with you, I didn't mean to be - I meant to be direct.

"No reason to be so strong with me..."

This statement concerns me a little. Would you prefer I use a feather boa next time? Please refer back to the aforementioned commercial.

If you want to continue to tilt at windmills here - knock yourself out.
georgehifi's avatar
georgehifi
10,312 posts
 
How to kill a thread "By Grannyrig"

Well this thread was going along nicely, until it turned into something personal, discussing the virtues of zero colouration of one resistor in the signal path against active preamps, tube or solid-state with 100's of different components in the signal path.
The simple truth, active preamps have colourations/distortions, because no two ever sound the same, (even though they measure flat 20hz to 20khz) that's why people keep changing them to get the colouration/distortion they can live with.
Cheers George
pubul57 OP
3,712 posts
 
George, other than providing a product category that people can build and make money on, I suspect that active preamps have their advantages, like running long interconnects, and providing enough gain and impedance matching to work well with almost any amplifier, a more universal application. So it seems they certainly have there place and serve a purpose besides simply adding coloration, and it might very well be that the very best actives converge in sound quality with an LSA, but will be able to provide the sound quality to a much broader range of listeners and system contexts. Any other advantages to actives?
georgehifi's avatar
georgehifi
10,312 posts
 
Yep, no arguments from me there Paul.
If you have less than 2mt interconnects a CDP or Phono Stage with less than 200ohm output impedance (which most are) and a poweramp with 47kohm or more input impedance (which most are), there is no need for preamplification, as it is a backward step in transparency to be true to the signal from the source.
Preamps in my view are a left over dinosaur from the analogue days before the advent of stand alone high gain phono stages and cdp/dacs with high outputs.
Cheers George
clio09
3,346 posts
 
If you need something that can drive long interconnects and provide impedance matching there are still active buffers like The Truth, Pass B1, and Burson Audio that will get you there while still providing a high level of neutrality.

The long interconnect advantage is really only valid for active preamps that are true balanced designs. Most audiophiles are running single ended systems and while you might be able to stretch the interconnect a meter or two further, I suspect it's the color of the month they're really looking for. On top of this perceived notion that 10db or so of gain is going to make a real difference in dynamics, slam, and 3-D presentation.
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