Zaphod Beeblebrox Posted July 26, 2013 Posted July 26, 2013 Just buy one from George. They're inexpensive, well thought-out and they sound very good indeed. There's a place for DIY and a place for buying the finished product. This is one of those times where buying the finished product is, far and away, the best decision.
WINEDS Posted July 26, 2013 Posted July 26, 2013 (edited) Just buy one from George. They're inexpensive, well thought-out and they sound very good indeed. There's a place for DIY and a place for buying the finished product. This is one of those times where buying the finished product is, far and away, the best decision. I have already built as per Georges published design on DIYAudio many years ago. They are indeed very well thought out and do sound quite exceptional! Edited July 26, 2013 by WINEDS
WINEDS Posted July 26, 2013 Posted July 26, 2013 This is much much more complicated, just so the matching of the led/ldr's can be less critical. And it definitely won't sound any better, maybe even worse, because the monitoring circuit is attached to the signal path (like a feedback network). Been there done that over the years with more experienced techs than you can imagine, and it's always been a head ache and a let down in the end. KISS is the only way to do it as I've described above. Cheers George Hi George, From what I understand Uriah is matching the LDRs as he did for a previous GB based on your design? I take you point about the monitoring circuitry though and will probably disconnect it. Just looking for the best way to get LDR attenuation with input switching and HT bypass plus IR control for integration in my home theater/2 ch setup
georgehifi Posted July 26, 2013 Posted July 26, 2013 Hi George, From what I understand Uriah is matching the LDRs as he did for a previous GB based on your design? I take you point about the monitoring circuitry though and will probably disconnect it. Just looking for the best way to get LDR attenuation with input switching and HT bypass plus IR control for integration in my home theater/2 ch setup Hi Wineds, the Lightspeed Attenuator is all about not having any contacts in the signal path, (volume pots or input source switching) For input switching I suggest something like this http://www.decware.com/newsite/rotary.htm that way when you want to hear or show off your system at it's best, you can still go direct into the Lightspeed with a source. As Audiophiles we want to hear the best when we sit down with a nice beverage and get off to the music sometimes don't we?. As for the ldr's they should be quad matched for a nice logarithmic control over the volume, not just pair matched, as that will give you control that can come on too strong at the beginning of the rotation and nothing after 12 o'clock or visa versa. Quad matching is the only way to go. And forget about a fixed resistor for the series component and an LDR for the shunt, this is what the MkI Lightspeed was years ago, and what all the Lightspeed clones from Asia and the US are doing now. Sure they are much much easier to manufacture but they don't sound nearly as good as the MKII, which is a quad matched set for series and the shunt component. All original MkI Lightspeeds were recalled and converted to MKII and everyone was over the moon at the difference. Saying that the MkI was still sounded better than a Blue Alps volume pot. Cheers George
WINEDS Posted August 9, 2013 Posted August 9, 2013 Hi Albert, for yours and others reading pleasure and info, below are two massive international forums that discuss the sound and benefits of the Lightspeed Attenuator. Also if you have basic electronic tech skills I have shown in the diyaudio forum a few pages in how to build one yourself. http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1276356977&&&/Lightspeed-Attenuator-Best-Preamp-Ever- http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp.html Cheers George Goerge I notice from this post you are now using a linear 100K pot whereas your initial DIyaudio design used a log pot?
georgehifi Posted August 9, 2013 Posted August 9, 2013 (edited) Goerge I notice from this post you are now using a linear 100K pot whereas your initial DIyaudio design used a log pot? Oops, sorry misprint, all fixed now, it's a dual log pot. http://www.stereo.net.au/forums/index.php?/topic/54566-lightspeed-attenuator/#entry920453 Cheers George Edited August 9, 2013 by georgehifi
alittlewino Posted August 9, 2013 Posted August 9, 2013 George, for us armchair people, when oh when will there be a remote volume version?? the decware switcher I can live with, but no remote………………………..
georgehifi Posted August 9, 2013 Posted August 9, 2013 George, for us armchair people, when oh when will there be a remote volume version?? the decware switcher I can live with, but no remote……………………….. You can get a cheap nasty diy remote, very coarse to use, and the hand sets last no time, and use my diy circuit with them, many there to choose from, but from suppliers that are here today gone tomorrow. http://www.ebay.com/sch/i.html?_trksid=p2051542.m570.l1311.R3.TR3.TRC1.A0.XRemote+volume+control&_nkw=remote+volume+control+kit&_sacat=0&_from=R40 My preference is for: 1: Good quality hand piece. (Try to find one that's not here today gone tomorrow) not those sh**y ones on eBay 2: A reciever board for that hand piece 3: Another power supply for the reciever 4: A good quality motorized 100k Dual Log pot (the only good one is Alps) 5: Another power supply for the motorized pot. 6: Then I would need a bigger chassis for it all Cheers george
amisty Posted July 26, 2016 Posted July 26, 2016 sorry to bring up an old thread but in the endeavor of googling trying to find ways of reducing the power output of my amp this came up! Does this attenuator work the same way as the inline RCA attenuators work by reducing DB? I ask in simple terms as I have no idea? cheers
Sub Sonic Posted July 26, 2016 Posted July 26, 2016 (edited) @@Zaphod Beeblebrox might be able to help answer your question. SS Edited July 26, 2016 by Sub Sonic
Zaphod Beeblebrox Posted July 26, 2016 Posted July 26, 2016 sorry to bring up an old thread but in the endeavor of googling trying to find ways of reducing the power output of my amp this came up! Does this attenuator work the same way as the inline RCA attenuators work by reducing DB? I ask in simple terms as I have no idea? cheers @@amisty Tell us PRECISELY what you are attempting to achieve.
amisty Posted July 27, 2016 Posted July 27, 2016 Ok This going to sound crazy but actually running the very inefficient Hifiman he-6 headphones where people use speaker amps and was recommended to find a class A . Couldn't find one in my budget but found one that was over powered in the budget. The Integrated amp is on at 20 out of 100 barely getting a work out for it to be loud and told i wasn't getting the full potential out of the amp due to the low volume and was told you will get better sound when amp is closer to half, so i purchased some some inline RCA inline -12db attenuaters Jesus what a difference i go to 35-40 now and the sound stage has opened up it was amazing i could hear all the finer details now! My issue is are they discoloring the sound in anyway/ affecting the sound? are there better options available to do the same job? this is where google has led me. Hope this makes scene. my Gear Cryrus cd transport > Klein DAC > then out to attenuaters into > Shangling integrated SLMï¼A40MKIII A class amp out put > to the he-6. Thanks
robmid Posted August 16, 2016 Posted August 16, 2016 (edited) I ordered a 23 step VALAB attenuator. They take a month to get to Aus but it vanished during shipping somehow. To save my sanity I decided to build George Stantscheff's Lightspeed Mk2 attenuator as a stand alone passive preamp so I could make a comparison. The Lightspeed has had many glowing reports, but some elecronic 'wizards' were complaining about lack of distortion figures and graphs so I was fully expecting the VALAB to sound better. I ordered 10 x NSL32SR2S opto couplers from Crest Components and got 2 sets of quad matches from 10 units. The first set of 4 matched within a range of less than 1ohm. Second set were all within 4% but 2 were way out with one being out by 30%. LIGHTSPEED SCHEMATICS HERE I grabbed a cheap 2 gang pot and 100 ohm resistors from Jaycar for a few dollars plus a $20 adjustable regulator kit which works like magic. (pic 3) It took me one day to build the reg kit and the attenuator which was built on a prototype board. After checking that the resistance on both channels varied when the volume control was rotated I hooked up the Lightspeed to my Holton amp with 33k input impedence per channel and KEF LS50's. I wasn't expecting such an enormous improvement in the already superb sound I was already getting with a shunted passive preamp and ALP Blue pot. Everything was tighter, and layered as I had never head before. Individual voices and instruments played together were not only positioned side to side but were sacked front to back and I could focus my ears to listen to individual instruments within a band. Everything sounded smoother but sharper with enormously powerful, tight, textured bass. MIND BOGGLING! Unfortunately, I had wire up the put in reverse and decided to fix my error. Stupid move. In the process, I may have cooked some of the optos because I had cut the leads too short and I mounted the opto couplers in pairs at the back of the board which is how I stuffed up the wiring. Luckily, I still had another set and more resistors and set of opto couplers but I also had learned a valuable lesson. KEEP LEADS LONG. Version two has the opto couplers mounted on each side of the pot with so they align with the appropriate input/shunt sections of the pot. (Pic 2) My box was built from jacaranda, sanded smooth and polished with Canuba wax. It not only sounds brilliant but smells great too! (Pic 1) I found the project to be fairly straight forward and parts very cheap, but I did tie myself up in knots with the first version through bad planning. Parts cost was around $160 including a Jaycar regulated power supply kit and heavy duty 2x6 position gold contact rotary switch. How does it compare to the 23 step VALAB attenuator? The VALAB was sharper (harsher) with muddier bass but better than my ALPS Blue pot. The Lightspeed is in a different league and the first note will stop you in your tracks. You must hear it to believe it. George charges around $500 for a built, single input Lightspeed which is good value if you don't want to tackle DIY. Edited August 17, 2016 by robmid 9
Addicted to music Posted August 17, 2016 Posted August 17, 2016 Don't take this the wrong way, admire your build and findings, but can you please correct the spelling mistake on the title of the thread. .
robmid Posted August 17, 2016 Posted August 17, 2016 YOIKS. I'm old and something must have been on my mind. Thanks.
Green Wagon Posted August 17, 2016 Posted August 17, 2016 YOIKS. I'm old and something must have been on my mind. Thanks. Probably had wood on the mind. Its what afflicts all men. So I'm told..................
Audionutz Posted August 17, 2016 Posted August 17, 2016 That about mirrors my experiences comparing my 10yo Lightspeed to everything I could get my hands on. Correctly implemented, it's pretty hard to beat. Cheers 'Nutz
Me2U Posted May 21, 2017 Posted May 21, 2017 I would like to qualify myself what I am about to write. I am 51, an engineer by profession, an ex-performing musician, home recording artist, diy enthusiast and an audiophile of more than 20 years. It is easy to understand that as an engineer it is obvious about my passion in all things diy. From my current rig consisting of a pair of diy 2.5 way floor stander speakers to my diy 300B/2A3 amp. In addition, as a Musician, my appreciation for music and especially high quality music reproduction is paramount. As an ex-owner of many hi-end audiophile hardware from speakers such as Kharma, Dynaudio, Vandersteen, Magnapan, Sonus Faber, to amplifier such as Audio Research, Plinus, Rogue, etc I am certainly experience and qualify enough to review hifi component, up to S$50K if putting a value to a piece of hardware means anything to you. To achieve commercial success in a product, you have to either sell a "need" that you make others believe that they need or you sell a solution to an existing problem that people are seeking. Lightspeed is a product that fall mostly to the later and appeal mostly to the diy community. By saying diy community I don't mean only those who seek to build an attenuator only but also those who are constantly searching for tweaks to their hardware such as Caps and tube roll or optimising an amplifier circuit. The writer is one such person. LS did no active advertising and I am ashamed to admit that as a self proclaimed audiophile for 20 years I chance upon the LDR circuitry in a diy forum only recently while seeking to improve my channel imbalance with the Alps variable resistor swipe type volume control. While using a contact cleaner did solve the problem somewhat, I explore deeper into the various types of attenuators. I assembled a 23 steps attenuator and realised my Alps variable resistor was indeed a bottleneck to my system. The 23 steps attenuator was like from winter to spring in my system. But I believe much can still be done to improve the performance. Than came the LDR attenuator. A simple and logical concept of using an isolated LED light intensity circuitry to vary resistance in another circuit hence producing a clean signal through the amplifier circuit resulting in crisp, clear, smooth, transparent and quiet layers of music only limited by the quality of the equipment downstream to the LS. The use of the stereotype audiophile jargon such as soundstage height/width, imaging, timbre, etc... is to me irrelevant in describing the LS. I believe an attenuator's aim is not to have a sound but to vary the signal level and passthrough effortlessly and not impeding the potential of your equipment. Any improvement gain is due to your equipment and LS is just an enabler. But I will certainly get bomb to claim the LS do not have a sound because the signals do run through some circuitry before it gets transmitted to your equipment. My point here is that if the LS produce a negative effects to your setup or swing towards certain attributes that is not to your liking, most likely the cause is a mismatch in impedance or you have a coloured attenuator and not the LS being inferior. Is the LS a plug and play component? No and maybe. First you need to make sure you don't have an impedance mismatch issue which is rare but not impossible. I have also a tube pre and SS power system and I lost the much preferred "tube sound" by putting the LS in place of my tube pre. This is not to say that it is terrible but not my preferred sound. I have now bypass my tube pre 23 step attenuator and use it as an over glorified tube buffer. If you are using a passive preamp the LS is a no brainier upgrade. If you have and like your SS pre, you will likely like the LS in place of your SS pre. Comparing my Alps to the LS is like winter to summer. It doesn't sound thin or dry on the contrary to some who have reported their experience. I recommend it highly if it fits you bill. A working LS circuit is available from a diy forum if you are a diy-er or are hell bend for saving up for other upgrade and only if you can find a match pair of LDR out of the many required for a project. I believe I can also make one from the available info from the internet but I choose to support the inventor who is passionate and generous enough to share his circuit and know how to the diy community in the numerous forum in the internet. His generosity proved that he is not a money grabbing person and in today's world such character is few and far between. The LS is where I stop my search for a better alternative for now. Buy it if it fits your bill before you consider an interconnect upgrade, tube roll, power cord upgrade, component upgrade. Most likely it is cheaper than other conventional upgrade path. DIY if you want and George will throw you his float when you are drowning. I hope the Lightspeed reach commercial success in a huge way in the future not that George care if it did or not. http://members.optusnet.com.au/~georgehifi/ PS: I am not affiliated to the Lightspeed product.
wizardofoz Posted May 21, 2017 Posted May 21, 2017 There are a few of us who have these here if you search.
DIYer Straits Posted May 21, 2017 Posted May 21, 2017 And I know someone who owns the Tortuga Audio LDR preamp. A local dude.
Me2U Posted May 22, 2017 Posted May 22, 2017 I don't know anymore about this hifi thingy.... it is becoming like a "black art". Lot of tweaks here and there to drive off the "evil spirits". Not so much about the LS being a black art but there are so much more to learn everyday. One local hifi shop here is selling those stickers tweak to put on caps and lots of people love it.
DIYer Straits Posted May 22, 2017 Posted May 22, 2017 I don't know anymore about this hifi thingy.... it is becoming like a "black art". Lot of tweaks here and there to drive off the "evil spirits". Not so much about the LS being a black art but there are so much more to learn everyday. One local hifi shop here is selling those stickers tweak to put on caps and lots of people love it. It's called salesmanship. The art of selling something that one doesn't need. Happens everywhere. As long as there are people with money, they will spend. You just have to know which button to push. The problem with Audio is that a lot of the science involved, has yet to be theorised empirically and reviewed by their peers. It is after all a relatively new field in Science. As a result, this gives rise to all kinds of claims and tomfoolery. Therefore, as with any sales transaction, Caveat Emptor. Isn't Audio great? (The scientific field, not the XP forumer.)
wizardofoz Posted May 22, 2017 Posted May 22, 2017 tomfoolery = audiofooleryv :o diy is still fun in audio and as long as it sounds good I will stick with diy solutions I do support the guys locally doing things that are what I need/like as long as reasonably priced too like the vinshine dac etc. There is much value to be had in diy if you are up for it, either building it yourself or sometimes buying someones efforts.
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