I have both the Bent and the LSA and plan to do a detailed review comparing the two.
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
Hi, I used to own the very highly regarded First Sound (active) preamp which was dual mono (2 volume controls, 2 input selectors) and it had 2db increments on its volume knob. I found the 2 dB step too large a size to get the volume just right. I much prefer the "infinite" vol settings on the Lightspeed. |
Yes 2 dB could be problematic in some instances. The 24 step switches with the S&B transformers wired to them were even more problematic since the first few steps were quite large increments, something like 6, 4, 4, and 3 dB steps before tapering off to 2 dB over the next several steps. My magnetic line amp uses stepped attenuators with 1.5 dB steps all the way through (41 steps in all). I find these to be useful. The continuous adjustment on the LSA works quite well for me too. Even matching both channels is quite easy. |
Hasn't made the website yet, but working on it. We need to officially dress one up and get pictures of it. Similar concept to the Decware CSP as the output voltage is adjustable, but we've added another feature that allows you to set up the output of the preamp using meters on the front panel. So when adjusting the output voltage so you can actually see how you are affecting the sound. If you want a hotter sound you can have that, something a bit mellower you can have that too. Tubes are mounted on the back panel so the preamp has a slim look to it. |
Just bought a LSA and got hooked up for 5 hours. got the best sound ever from the system with loads of beauties, transparency, tonality (especially bass), and dynamics... This is the component that blows me away from all the perspectives of value, performance, and design concept. Salute to George and thanks all in this thread for the guidance. |
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 |
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? |
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. |
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 |
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 |
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. |
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. |
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 |
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? |
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 |