Has anyone made a balanced version? Is it possible to purchase a balanced version?
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
lordcloud I've tried many different ways all a compromise, or not reliable over time. I don’t do them and I suggest you don’t use them. It can’t be done reliably in the "purest" way of making the Lightspeed Attenuator circuit that gives it it’s magic, and also ask it to stay in calibration over time. https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp.html It can only be done with active force matching circuitry that’s a compromise to the sound in itself, and "can" damage one or more of the 8 led/ldr’s in the long run from over driving them to keep up with the stronger ones. Your better off using xlr to rca adapters as my customers use when they have no rca connections, only xlr, these works great. https://www.parts-express.com/xlr-female-to-rca-female-adapter--240-428 https://www.parts-express.com/xlr-male-to-rca-female-adapter--240-438 Cheers George |
One thing that I didn’t mention, was that xrl only sounds better than se over very long distances. In many cases se actually sounds better, if an opamp was used to make the xlr circuit in your equipment, and you’d be very surprised to know just how many do it that way in many hiend products. . Cheers George |
I am so impressed with Lightspeed Attenuator. HUGE sound improvement!! With
80-85% of regulated analogue output on Oppo UPD-205 player and around
11-12 clock on Lightspeed, I am getting MUCH more balanced, realistic
and pleasant sound. This is with mild to medium speakers' loudness
which I use 95% of the time. Improvement is very obvious across all
sound spectrum, but is extremely obvious in the voices. I
always pay paramount attention to the voices. To me, if the voice is
compromised, nothing else matters. In
comparison, without Lightspeed (or with only 20-25% of regulated
analogue output on Oppo UPD-205 player and max volume on
Lightspeed), the sound is MUCH less articulated, less pleasant and less
realistic. This is very obvious in all sound spectrum, but is
extremely obvious in voices. Again, this is with mild to medium
speakers' loudness which I use 95% of the time. Blue label on the Lightspeed box is a great match to other
blue lights in my audio. Very thoughtful, George.
Audio system: Voltage stabilizer: Line-R; Cawsey power cleaner; Aurealis: speaker cables and copper interconnects Litz Dragon; Oppo UPD-205 player/streamer; Lightspeed attenuator; Cymer Audio Southern Star SE-35 power amp; Osborn Epitomes Elite speakers. |
Important Update: 1. I think Lightspeed Attenuator is not an accessory, but a MANDATORY component for most audio systems because the difference is unbelievable. 2. I believe that DUAL volume control is a MANDATORY. It is very useful not just for vinyl records (which half of audiophiles don't use), but nearly for EVERYTHING: to compensate room settings; to compensate your sitting position; to compensate inferior audio recordings (common); inferior sound recording in movies (very, very common). |
| Post removed |
brewmasterdon Self confessed troll, you need to be banned. Maybe you should stick your active preamp down your throat instead, it probably fits. |
| Post removed |
The best preamp I have used.
I thanked Georgehifi from the bottom of my heart for the Lightspeed passive preamp. It really elevated my system which comprises Sony HAP Z1ES for transport and LX521.4 speakers. His preamp is the best thing that I have ever done for my system. It has made my system so transparent, clear, and luxurious. I cannot imagine any better preamp ( my experience is obviously rather limited but I just cannot imagine anything better) and I deeply thank you. I certainly do not need to upgrade my preamp. |
Thank you Sean for the very favorable mention of the Lightspeed Attenuator. I just had a good look at these highly regarded Linkwitz Labs speakers of yours, very elaborate for a diy'er to do, one needs to be on the ball to make these. (and have some time on their hands). https://www.linkwitzlab.com/LX521/LX521_4.htm Cheers George |
ledoux1238 Yes it does, it’s a $35 option, and is good for recording, room or system imbalances, also great for vinyl, as I never seen cartridges that have perfect channel balance. It’s all in the sales/pricing info I send in emails to customers, if you want it send me an email to georgehifi at optusnet dot com dot au Or if you have the skills, you can make your own at diyaudio forums, where I explain how to do it. https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp.html Cheers George |
Got one of George's Dual Vol units a few weeks ago. Been doing some casual and a little critical listening (don't do much of that anymore, can't enjoy the music) over the last week.......what can I say....there is sooo much detail coming from my system with this unit, it is certainly highlighting ordinary recordings that I thought previously were ok. On good recordings bass seems tighter and more detailed and in particular vocals and drum kit are crystal. As George mentions above, this is about as "straight wire" as you can get. Currently running with a JOB225 power amp; Audioengine streamer and pair of Elac B6 speakers. Seems a good match for the JOB. Am going to switch out my MF tube X-Pre and run the X-A50 momoblocks with the Lightspeed and see how it goes. Thanks George. Cheers, John |
This thread has had 18 million views... that is nuts. I had a lightspeed years ago. Should have never sold it. They are the best preamp for the $ no doubt. It really does just get out of the way of the signal. You do need proper gain matching but if you have that, a good dac and a good amp, the lightspeed is just awesome. |
This thread has had 18 million views... that is nuts.Yeah Bruce, and the amount of PM’s are even more nutz to reply to. They pop up used sometimes for around $200-300usd there are over 950 units out there all over the world, just email me if you decide to get one of them for the correct wall wart for the US. And thanks for that rap! Or if your electronically minded, you could make your own, that I show how to do here. https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp.html Cheers George |
Let me start by saying that I have read every post in this gargantuan thread. Every. Single. Post. I agree, the LightSpeed Attenuator is a mandatory component of any audiophile-level sound system. I love mine so much that I might attempt to build @georgehifi's DIY instructions. And this from someone who has two left hands. I want to see a bit of what George saw when he envisioned this masterpiece. Of course, get the dual volume version. It's the only version I considered. The speakers in my system are Canton Reference 3.2 DC. For the life of me I couldn't figure out why these speakers were so undervalued. These 110 lb behemoths when powered properly with decent room acoustics give a sound of true unadulterated bliss. I decided to go with the discontinued Classe CT-M600 monoblocks. I read a number of reviews but it was Audiogon user caphill who wrote: "Dynamic headroom and bottom end extension and control are excellent. The Classe CAM 600 excels in extracting musical details and nuances and information. The tonal is neutral and balanced across the entire spectrum with a touch of warmth. The noise floor is one of the quietest I’ve heard from any high end amplifiers. The amps are dead quiet and the music emerges from a dark black silent backgrounds." Enough said. But it is the invaluable LightSpeed Attenuator that ties all this together. When purchasing the new pieces for my system, it was the LSA that I purchased *FIRST*. Sight-unseen, untested, and unheard based on reviews from Audiogon. The LSA gives you the feeling that you are listening to the voice of God. The sound is so enjoyable so ethereal. The LSA simply gets out of the way of the music and passes on exactly what is on the recording. Few if any products actually accomplish this. I just don't have the words to properly convey how I feel about this setup helmed by the LSA. It goes without saying that georgehifi is a genius. And a very kind and generous soul who could have easily sold his invention for 10-100x the almost insignificant price he is charging. Thank you so much, George! The LSA is a priceless creation that everyone should hear and own. |
zeusodin Thanks for the great Lightspeed rap and kind words zeusodin, if you want to experiment a little it's only a slight improvement over the linear regulated supply the Lightspeed has already to control all the LED's brightness. And that is to power them using this 12vdc CCTV Li-Ion rechargeable battery setup, cheap enough for the slight improvement. Just make sure with the seller that it's 12vdc and that the dc plug that goes into the Lightspeed is 2.1mm X 5.5mm and HAS to be positive centre. https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2540003.m570.l1313&_nkw=12v+cctv+lithium+... BTW all, I've halted all OS orders for a while as the last one took nearly 3mts to get to it's destination, the postal service all over the world is shot to hell, I'm also finding parts getting to me are taking twice as long. Cheers George |
| Post removed |
Glad someone else is enjoying the Lightspeed. I have owned mine for over 10 years now. I also have the dual attenuators and while they work just fine, I have often wondered if there is a stepped attenuator alternative. IIRC the Lightspeed uses a 10k log attenuator, but perhaps the Khozmo or Goldpoint attenuators can work as well. Any comments from George or others who have done this would be appreciated. |
Good to see your still enjoying them clio09 yours are getting on in years now, there are over 1000 units now out there world wide of the MkII like yours. And probally twice that of diy ones that made them here. https://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-passive-preamp.html This is for others as I think you know. You could use stepped potentiometers, but they only control voltage for the led’s, so quality is not that important, no advantage sound wise by using Khozmo’s or Goldpoint’s. They don’t have anything to do with the music signal they just control the 4x "led" lamps brightness’s which in turn shines on and changes the resistance of the 2 x light dependent resistors "ldr", that "are" in the music signal and another 2 that go to ground. https://www.diyaudio.com/forums/attachments/analog-line-level/470539d1425885769-lightspeed-attenuato... Big changes coming soon for Lightspeed Attenuator, I’ll let you know when it’s the right time. Cheers George |
@georgehifi, I saw both of those links and the reason I want to use stepped attenuators is not because I think it will provide better sound, but just being able to count the steps on each channel for balance purposes. I know it sounds silly but I have some of these lying around anyway, including some nice Noble stepped attenuators from years gone by, so why not give it a shot. If I understand the second link you posted the value is a 100k dual log pot. Not sure if the Khozmo or Goldpoints that I have are log, but the Noble is. If I use dual attenuators I assume the value is the same. Keep me up to date on all things Lightspeed. I’ve gotten great mileage out of mine. |
Let us know how you go, one wire at a time, to dismantle unscrew the front pull out slightly and lower then the top lid slides out. (don’t try to access from the back, not possible) Dual mono https://www.diyaudio.com/forums/attachments/analog-line-level/470540d1425885769-lightspeed-attenuato... Stereo https://www.diyaudio.com/forums/attachments/analog-line-level/470539d1425885769-lightspeed-attenuato... Cheers George |
QSA fuses are the best aftermarket fuses I have tried. Tweek Geek has them and offers a trade up program and 30 day money back guarantee.They’re awesome! https://www.tweekgeek.com/qsa-quantum-science-audio/ |
QSA fuses have been a great addition to my components. Thanks to bringing my attention to how great a QSA fuse can improve the enjoyment of listening to music. https://www.tweekgeek.com/qsa-quantum-science-audio/ |
@georgehifi, As I review the schematics and look at the actual pots in the Lightspeed I'm wanting to confirm that the middle tab on the pot is the ground and the other two tabs are for the input and output. I ask because the Noble stepped attenuators do not have the ground on the center. I'm not sure it matters as long as ground is hooked up correctly, but just wanted to check to be sure. |
@georgehifi, on a pot the middle tab is the wiper or output if I understand correctly and if I understand you correctly this is positive. Based on the physical layout the positives of each switch are connected with a red wire and then there is a red wire from one of the switches to the board. Well I installed the stepped attenuators using the same method. I believe I hooked up the other wires correctly as well, but here is my issue. With the original pots the Lightspeed never fully attenuated the sound, the pots in full counter clockwise positions still resulted in some low level sound coming from the speaker. I get the same result with the stepped attenuators, only the sound is much louder, in fact I could just listen to the music without moving the switch clockwise. If I do move the switch clockwise the volume does increase, but not very dramatically. In full clockwise position the sound level is still reasonable. Something is amiss. Any ideas? |
First off clio, are you 100% sure the new ones you bought are 100kohm logarithmic and not 100ohm logarithmic or even linear??? @georgehifi, on a pot the middle tab is the wiperYes on the dual mono it is, and where the + of the power supply goes. But not on the stereo if you look at the circuit. With the original pots the Lightspeed never fully attenuated the sound, the pots in full counter clockwise positions still resulted in some low level sound coming from the speaker. I get the same result with the stepped attenuators, only the sound is much louderThis is correct, all Lightspeeds Attenuators can never attenuate to absolute zero, as the LDR’s can never go to 0ohms, or complete open circuit I get the same result with the stepped attenuators, only the sound is much louderIf all was wired up as the original/s were, the problem must be that the pots you bought are either not 100kohm, or not logarithmic but linear. If they are 100kohm and logarithmic, then the first step up in volume must be way to high. If I do move the switch clockwise the volume does increase, but not very dramatically. In full clockwise position the sound level is still reasonable.If 100kohm value and log curve are correct ,this says to me you’ve wired it up wrong. The only thing I can suggest then to do is put back the original pots and see if it all goes back to normal, if not you’ve wired it up incorrectly Cheers George |
To all the "Lightspeeders" here at Audiogon and any new ones OK, time to let all here know that Lightspeed Attenuator has been acquired by a most avid audiophile, and who will do it proud. His name is Scott Campbell who also resides in Australia in the Sydney country side town of Green Point. He’s been very committed hi-end audiophile for as long as I can remember. As for his component history I’ll let him tell you. It was time to let it go after all these years, because it was starting to feel too much like “ground hog day” to me producing them. He also won’t be doing any orders for the time being, because of the Covid outbreak here, and he will also need to setup his production premises. His present email is Audio@tradeontheweb.net but no doubt will have another soon, more akin to Lightspeed Attenuator name in the future. I will still be around for tech assistance, till he finds his feet. Cheers, and a very big thanks for all your support George |
Thanks George & thanks for the kind words. I’m a passionate audio guy of 60. I’m very proud to have this opportunity with a product I’ve used personally for over 10 years. George has kindly agreed to remain on in a support role & I'm fortunate to have his knowledge to call upon when needed. I have some future plans for the Lightspeed, but for now the focus is on supporting existing owners & getting production up & running, once Covid allows. Cheers Scott |
@georgehifi, after fudging around with it some more the wiring was not the issue, the amp was. I pulled one off the shelf that I thought was good but is actually in need of repair. Pulled another one out and all is well. Great news about the Lightspeed. Looking forward to Scott keeping this legendary attenuator alive. |
| Post removed |
The sources volume should be controlled up and down that’s all. (nothing added or subtracted) The well known saying, "the best preamp should sound like a piece of wire" not adding or subtracting anything from the sound of the source, and if you don’t like it, you don’t like something else in the system, better to fix it. The closest in order to "sounding like a piece of wire" and being "the best preamp", most transparent of all without colourations or distortions are: 1: Direct source to amp connection, if!! (the source has a digital domain volume control, and it’s not use below 75% of full, as not to "bit strip the music") 2: All passives (except tvc’s), if the system permits impedance compatibility (most do) 3: Active preamps + tvc's, which have colourations/distortions, (that’s why they all sound different), and may suit if finding the right one to mask the problems with source or system, but in doing so they ruin the transparency, and add colourations. (to me it’s better to fix the problems and have it all) Cheers George |
There are some instances where additional gain is needed, namely analog sources, so the MP3 comes in handy for that. On the digital side the Lightspeed is the solution. Like our old friend pubul57 (Paul, RIP) who started this thread years ago one of the best setups for the Lightspeed was digital source > Lightspeed > Music Reference RM-10 (or RM-9SE). Tough to beat that combo and an incredible value too. |
There are some instances where additional gain is neededYes that needs to be added to No.2 " 2: All passives (except tvc’s), if the system permits impedance/gain compatibility (most do) Like our old friend pubul57 (Paul, RIP) who started this thread years agoYes we all miss him dearly. Cheers George |
| Post removed |
@cerberus79 You/we are lucky GK has disappeared (or been banned) he was a real comic piece of work but fitted in well in these types of threads, and his website is really out there https://www.machinadynamica.com/machina5.htm best one is the pebbles. As for your Maggies I had quite a bit to do with them owning the big Tympanies also, before going on to big ESL’s. cerberus79A few months ago I purchased a used pair of speakers from another Agon member. To my surprise all the fuses were Orange fuses. I listened to them and then to satisfy my curiosity I replaced them with ordinary buss fuses and could not hear a difference. I did this test with a bunch of friends and neither I or them could hear a difference. As you stated no difference in sound whether 10cent Bussman fuses were in or $150 SR Orange were in, to yourself or when the guys were around to do the A/B with. cerberus79 Same thing I say to them, if it’s directional then it’s trying to be a diode, and that NOT good in either direction! But I can tell your Maggies will sound a touch better with just a piece of copper wire soldered lightly outside of the fuse clamps and no fuses. This makes them vulnerable to an amp blowing and going dc, as you know having electronic knowledge background, but no more so than any other speaker would have no dc protection either. You could try one of these if you want to retain the protection soldered to the fuse clamps. https://www.jaycar.com.au/5-amp-circuit-breaker/p/SF2254 |
@cerberus79 You/we are lucky GK has disappeared (or been banned) he was a real comic piece of work but fitted in well in these types of threads, and his website is really out there https://www.machinadynamica.com/machina5.htm best one is the pebbles. As for your Maggies I had quite a bit to do with them owning the big Tympanies also, before going on to big ESL’s. cerberus79A few months ago I purchased a used pair of speakers from another Agon member. To my surprise all the fuses were Orange fuses. I listened to them and then to satisfy my curiosity I replaced them with ordinary buss fuses and could not hear a difference. I did this test with a bunch of friends and neither I or them could hear a difference. As you stated no difference in sound whether 10cent Bussman fuses were in or $150 SR Orange were in, to yourself or when the guys were around to do the A/B with. cerberus79 Same thing I say to them, if it’s directional then it’s trying to be a diode, and that NOT good in either direction! But I can tell your Maggies will sound a touch better with just a piece of copper wire soldered lightly outside of the fuse clamps and no fuses. This makes them vulnerable to an amp blowing and going dc, as you know having electronic knowledge background, but no more so than any other speaker would have no dc protection either. You could try one of these if you want to retain the protection soldered to the fuse clamps. https://www.jaycar.com.au/5-amp-circuit-breaker/p/SF2254 |
tomic601 Yes Scott (new owner of Lightspeed Attenuator) in the future said he'll have remote, and maybe a more glitzy look. Something I always meant to get around too, but never did. My proposed path; Herron phono pre >>>> Lightspeed >>>> RM-9Should be a great setup as the Heron has ample switchable gains https://ibb.co/qYSnCLx for your vinyl. Cheers George |
Don’t know what this clown 3 posts back hopes to achieve by copy/pasting exactly something I posted on a totally different thread about fuses, as the Lightspeed doesn’t even use fuses!!!!!!!!!!!. (there’s always one, probably a fuser) But he managed to bump the thread which is good. Which created us to chat about the Lightspeed Attenuator and to give Scott (new owner) more exposure. Cheers George |
George Stantscheff, thanks for introducing me to Quantum Science Audio fuses. They’ve been a great addition to my system. While I don’t own a Light Speed Attenuator I do want to learn more about them. I’ve seen most light dependent resistor preamps measure poorly. How does your design work around that? |
| Post removed |