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
knghifi
1,668 posts
 
That's my point, there are no perfect cds (over 80% are compressed. I like the music but recording sucks), source and interconnects. By the time the signal reaches the preamp, it has been altered. So what you are saying is if you like the sound of a passive, you prefer how the source and interconnect altered, amplified, added / subtracted ... tone controlled the signal.

I don't understand the statement if you prefer active, therefore you prefer a tone controlled signal. This is only TRUE if the preamp is the only component in the system. The signal gets altered as it travels through the chain of components. But I do see an advantage of a passive preamp in an integrated amp.

Let's agree to disagree and move on.
clio09
3,355 posts
 
Let's agree to disagree and move on.

Isn't that what we've been doing for the last 8 pages and nearly 400 posts:)

Let's face it, we're relying on the recording engineer to interpret the event and put it down in as accurate a means as possible given their hearing skills and the equipment used to mix the recording (the first introduction of tone controls). I agree with Knghifi that most recordings are awful. So the process is flawed from the start.

To listen to what the recording engineer intended us to hear, we have to rely on a means to reproduce the sound of the recording. What that means is comes down to preference (and what we can afford). One such preference is to use as few components as possible in the signal path to eliminate unwanted artifacts and coloration. It's not a perfect means (we still have other tangibles to address in the process) and it may not give us the sound we prefer. It's just one means and the one I and others here subscribe to.

But I do see an advantage of a passive preamp in an integrated amp.

Ralph Karsten has indicated that the best approach to addressing passive attenuation is to implement it at the amps input. He offers such an upgrade for his amps (M-60 and above). It certainly simplifies the process (one less set of interconnects) and I wish more designers would offer this option.

Maybe George can come up with a module based on the Lightspeed design he can OEM to amp manufacturers;)
fiddler
581 posts
 
Knghifi, with all due respect, you can move on at any time.

The discussion regarding "coloration" and "alteration" of the original signal by EVERY component is a legitimate discussion here. As much I enjoy some things that tubes do (I have them in my system), there is a limit to the tube "effects" that I am willing to accept.

As I stated earlier, I was surprised to hear just how little my Supratek altered the signal when compared to the LSA. They are virtually indistinguishable. That's why I opted to use the lower maintenance, no-heat LSA instead.

No one is passing judgment here on whether another person should or should not like a particular component's coloration. Clearly there are those who attempt to hear the original source as close as possible and then there are those who prefer the addition of some tube euphonics (I'm one of them). That's not to say that either is right or wrong, it is merely a personal preference.

However, there can be no debate that the LSA adds less to the signal than your VAC preamp if you are hearing more artifacts from the VAC. It is clearly not debatable. Now does the VAC make the music sound more real to you? That is another question. But sounding more real versus accurately reproducing what is on the recording are two different things. Let's face it, some recording are done so poorly that it does sound like something is missing and that something does need to be added. The only problem with a component adding to a bad recording is that the component is also adding to good recordings. The simple question remains - does your ear like what is being added. That's all that matters.

That's why Baskin Robbins sells 21 flavors.
grannyring's avatar
grannyring
6,471 posts
 
Knghifi, I made the exact same point on this thread a while back. I follow what you are saying and it strikes me as the correct way to look at this. This is a very interesting discussion and the main reason I keep looking at this thread.

I tried the Lightspeed and found my active preamp to be more "accurate" to the recording. I am very intrigued with this debate and hope it continues.

I am certain my preamp is not adding distortion or fuzz or any additional "stuff" unless my hearing is not as good as I think :-)

Things like stage depth, dimensionality, micro details, tone etc... make a stereo system sound more like music and more like a wonderful recording. Not sure distortion of any kind would ever help these things? The active delivered this better in my set up.

I bet a passive does this better in some systems. The reason - because the music that emerges from a stereo system is the sum of ALL the parts.
pubul57 OP
3,712 posts
 
I am sure I would like the VAC too:)
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