There is no way around the lack of muting issue at "0" from what understand, unless you unplug the LSA.
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.
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.
1,866 responses Add your response
Paul, yours will either look like this (pic at top of page): http://www.intactaudio.com/atten.html or this (pic at top of page): http://bentaudio.com/index2.html Mine has the first one. The later Tap-X units have the second one. |
Anthony, it looks like the Slagle auto former with the Chapman board is the one being used, I take it that is a good thing. I assume the Bent TAP-x I owned with the Slagle a few years back was using exactly the same thing. Getting silence at "O" seems to be impossible with the current LSA MKII design, where as the less good sounding MKI could. I'm sure George will be able to explain why. |
If indeed the EMIA uses the Slagleman autoformer modules with the circuit board designed by John Chapman then the only nit I have is the inexpensive switch used. If they use the OEMed modules that John Chapman offers (which I think is the case with the remote version), then this would change things somewhat. Paul, have you peeked inside yet? Can you tell me what version of the autoformer is being used. I have to admit Jeffrey Jackson does outstanding woodwork. I have decided to have my woodworker build me a nice box and I will re-house my Slagleman modules inside it. |
I sold the LSA and just got the Emia a few days ago 9 can't imagine many have been sold yet) (currrently $1,250) because I felt the need for balance controls (room, ears, recordings). After sometime assessing the Emia, I will also be getting the LSA with dual volume controls to compare A/B as I did not have both at the same time - though without "steps" might be a PIA making adjustments. To some extent, Clio9 has already made the comparison between Emia and LSA as he owns a passive based on the Slagle Slagelformer AVC, which is essentially identical to the Emia, though Emia makes "artful" cases. Clio9 seems to love both with a slight preference to the LSA, which might very well be system dependent (he wrote a "review" comparing them on Agon). Obviously the AVC is more"impedance flexible" than the LSA, but the LSA purer, and considerably cheaper. Whatever the case, from the time I have had with the Emia, and Clio9 with the LSA, they are both wonderful passives, and if passives can work for you, both worth considering, the LSA being the obvious bargain financially, and in the right system, perhaps sonically too, as there is simply less there interfering with the signal than with an auto former, but you signal may need "conditioning" to work optimally depending on your system. I think Clio9 has heard more passives than any person in the western hemisphere, and LSA seems to be his preferred option as this time, but there are other options that might be better suited to certain system requirments. In my system the LSA was unimpeachable sonically - at least for my taste. If you need absolute attenuation, the LSA may not work, how sensitive are your speakers, what is the voltage of your source[s] and sensitivity of you amp? George or Clio9 might be able to give you and idea of how much of an issue it might be for you - in my case it was a non-factor. |
What is your concern? You have very high gain speakers and very high sensitivity amp and are concerned that you cannot get the volume low, in fact to high for background music? What gear do you have that gives rise to you concern? With my 89db Merlin's, and .8v RM10 amps there was no problem at all, though you can not make it absolutely silent, if you need to do that, I don't think you can use an LDR.. |
I kinda think it is the best volume control ever. I've tried full preamps from ARC, Rogue, Placette, some TVC, battery tube buffers with goldpoints and a few other oddities in a vinyl only system. Can't duplicate the blackness and the natural ease of the musical flow. Fantastic product. The DIY ones (boards offered with George's blessing I'm told) sound equally great if you need to create something that matches the look of the rest of your system or need multiple sources. |
Hi Kevin, the distortion that the NSL32SR2S LDR's is .02%. This is also 2HD the nice one that tube amps and preamps give, but in a low feedback SE tube amp case this can be much higher at up to 2%. So as you can see .02% is nothing and it's the nice tube sounding one. Also I saw that quote and it is also based I think using the Vactrol ldr which are inferior to the Silonex NSL32SR2S for both distortions and impedances. Cheers George |
Hi all, As a Lightspeed customer I came across someone saying that when it comes to nonlinear distortion in the audio range, LDR's are pretty dirty. I know that there is no perfect product, but would someone care to explain and validate this assertion please? Am I hearing the distortion at a certain vol level across all frequencies or at certain frequencies across all volume levels, or something else? |
I completely agree. It's a shame they've removed the ability to communicate with each other outside the forums. In their effort to increase profits, they're killing our community. It makes you wonder if the site is about high end audio or just high profits. Their traffic is steadily declining since their redesign. Check it out: http://www.quantcast.com/audiogon.com |
I don't understand it, it is certainly not a privacy issue in my view, in fact how would I contact any of you privately now other than to post by e-mail or phone number on a "response" - this is not a user friendly change. I suppose they did it to prevent folks from buying and selling though the AGON process rather than dealing with each other directly to avoid the 2% transaction fee - I assume they had a reason and that this is not simply an oversight. |
Clio might be out and about, but on the famous DIY thread, George said: "Hi guys, saw this thread when I Googled my Lightspeed Attenuator. Just to clear up the impedance matching issue. For a good match in a system the Lightspeed Attenuator should see: 1 A CD player or Dac that has an output impedance of less than <1kohm (1000ohms) 2 The poweramp solid state or tube should have an input impedance of more than >47kohms (47K) When these parameters are met you will have the deepest cleanest bass, most dynamic transients, most transparent sound stage and cleanest sweetest highs, you have heard." Then there is the issue of theory and listening, Clio9, as he mentions earlier in this thread, for example has had good results with amps than in theory had too low an impedance for and ideal match, but it worked in the listening. |
Any cable that is below around 150pf (picofarad) per foot is considered to be low capacitance. This is a specification that should be advertised with all cables bought on the packaging. A manfacturer worth his salt should be able to tell you what his cable measures if you email them, if not stay away from that cable. Cheers George |
I had to look at the Stereophile review of the Rega Dac to find out. It's the only place I could find what it is, even the Rega site doesn't say. They (Stereophile) measured it at 620ohm, strange this is quite high for a solid state output I wonder if it's correct, email rega direct and ask. But it should pose no problem if it is to your setup, just keep your interconnect short and low capacitance. Cheers George |
The input sensitivity and input impedance of your amp are fine. The input impedance is 47k ohm which is at the lower end of what the LSA likes to see but will be just fine as I've used mine with lower. The output voltage of your Rega DAC is fine too. What we don't know is the output impedance of the DAc but given that it is a solid state output it should be under 200 ohms so you will be fine IMO. Give it a listen. |
Just picked up a lightspeed. Here's what I have,how can I get it to work best with the lightspeed. Krell KSA 50S amp Music hall CD 25 transport - Black Cat Veloce ic - Rega DAC AU 24 ic or Straley ic or Morrow ic to preamp same to amp Clear Day or Straley speaker cable to Tekton Lore My ears are the ultimate test but am I off to a good start? |
Just in case some are wondering, Tristone (Lei) ordered a dual mono unit, these seem to be gaining popularity as it gives audiophiles a balance control being separate left and right volume controls. I still recommend the stereo unit if your room and system are balanced from left to right, as dual mono can be a little less user friendly to use, as the famous Audible Illusions 3A's used to be if you ever lived with one. I know some her have built their own Lightspeed clone from the circuit boards that are available on DIY forum, so I have posted up how to modify the circuit board for dual mono use should you wish to do it. Here is the link. http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp-443.html#post2944737 BTW Tristone thanks for the rap!! Cheers George |
