snip
as for the distortion, I challenge you to hear the difference between .001% and .1% on a system, and that .1% distortion is at 2volts rms, show me a cd player or dac that gives 2vrms, while playing music, it would blow an amp to kingdom come.
Heinz you have yet to hear one of these. Do yourself a favour and listen to one, I'm sure you'll change your views towards them.
Ok George, I will not hear a difference (but may be other), also because I go from audio to industry (amp) design 1982 and today I hear very seldom music ... it`s to noisy!
BUT I like till today "perfect" things, that`s also necessary in my business.
And as I said before I will compare a LDR attenuator with other ones.. in ALL perspectives!
So I think how to eliminate the main "disadvantages":
1. Stability (Temp/Time)
2. Equality
3. Distortion
and I believe that together with a little bit more "electronic" one can get a fare more "perfect" thing
Regards
Heinz
as for the distortion, I challenge you to hear the difference between .001% and .1% on a system, and that .1% distortion is at 2volts rms, show me a cd player or dac that gives 2vrms, while playing music, it would blow an amp to kingdom come.
Heinz you have yet to hear one of these. Do yourself a favour and listen to one, I'm sure you'll change your views towards them.
Ok George, I will not hear a difference (but may be other), also because I go from audio to industry (amp) design 1982 and today I hear very seldom music ... it`s to noisy!
BUT I like till today "perfect" things, that`s also necessary in my business.
And as I said before I will compare a LDR attenuator with other ones.. in ALL perspectives!
So I think how to eliminate the main "disadvantages":
1. Stability (Temp/Time)
2. Equality
3. Distortion
and I believe that together with a little bit more "electronic" one can get a fare more "perfect" thing
Regards
Heinz
Too much perefect specs can be a bad thing, trust your ears and the specs. We can always hang plenty of feedback around amp thing to make a perfect spec, but not awalys for a perfect sound, I noticed you listen to some Class D amplifiers, You could'nt pay me to try to enjoy a Class D amp, I also love to listen to good high power (50watt) single ended DHT 805 tube amps, shocking specs great sound. As always trust your ears.
Cheers George
Cheers George
?? Never heard such a amp though a build a lot of them,
gfinlayson said:
Agreed, it's not a problem at all, it's the cleanest most transparent active preamp or passive-preamp that I've ever listened to, and it goes from dc to gigahertz in frequency.
Even if it did manage to give 0.1% distortion, it's second harmonic in nature which is pleasing to the ear, not that you would hear .1%. Some good tube amps give more than 1%, a lot of them are hard to beat sound wise, not to mention speakers, up to 10%
All of my customers have said that when they have used the Lightspeed Attenuator, it's been the blackest background they have heard on their systems. So feel confident in making one and report your findings back here, I would love to hear your comments.
Cheers George
Apparently Not Long Lasting
Am I reading page 37 of the Perkin-Elmer specification correctly? These units change resistance at the rate of up to 10% per year? The useful life expectancy is around 1000 hours? Wow, the guys who sell preamps with these volume controls have a better racket going than the phonograph cartridge people used to.
The average phonograph stylus lasts about 1000 hours, too.
As I said, I'm really very happy with my twenty-year old Penny & Giles fader. I just checked it for tracking and overall resistance. Dang if that piece of junk isn't still within 1% of spec after two decades of constant use.
Oh, and I checked with Penny & Giles. The wipers on their faders do NOT use a "feather weight" wiper system, and contact bounce doesn't occur until the AC current through the pots exceeds a value that would cause your LDRs to catch fire.
One of the reasons that it still requires a good sized knob to turn it is that the wipers have plenty of pressure on them and there is noticeable friction as a result.
The Clarostat factory in Mexico told me the same thing. Conductive plastic potentiometers won't work unless there is considerable pressure on the wipers. It's actually a design objective to figure out how to make the element as small as possible so that the applied torque can be reduced. The brand new Clarostat precision pots that I just bought for my new microphone preamp came straight out of the box within 1% for overall resistance and matching each other within 0.1%. Not bad for a couple of precision conductive plastic pots that cost $25 USD delivered to my door by Newark.
I don't know where you get your information, but the manufacturers of the pots seem to think you are misinformed.
Am I reading page 37 of the Perkin-Elmer specification correctly? These units change resistance at the rate of up to 10% per year? The useful life expectancy is around 1000 hours? Wow, the guys who sell preamps with these volume controls have a better racket going than the phonograph cartridge people used to.
The average phonograph stylus lasts about 1000 hours, too.
As I said, I'm really very happy with my twenty-year old Penny & Giles fader. I just checked it for tracking and overall resistance. Dang if that piece of junk isn't still within 1% of spec after two decades of constant use.
Oh, and I checked with Penny & Giles. The wipers on their faders do NOT use a "feather weight" wiper system, and contact bounce doesn't occur until the AC current through the pots exceeds a value that would cause your LDRs to catch fire.
One of the reasons that it still requires a good sized knob to turn it is that the wipers have plenty of pressure on them and there is noticeable friction as a result.
The Clarostat factory in Mexico told me the same thing. Conductive plastic potentiometers won't work unless there is considerable pressure on the wipers. It's actually a design objective to figure out how to make the element as small as possible so that the applied torque can be reduced. The brand new Clarostat precision pots that I just bought for my new microphone preamp came straight out of the box within 1% for overall resistance and matching each other within 0.1%. Not bad for a couple of precision conductive plastic pots that cost $25 USD delivered to my door by Newark.
I don't know where you get your information, but the manufacturers of the pots seem to think you are misinformed.
chewrock, mine are'nt the Perkinelmer ones, mine are from a different company, also I told you they have been on now for 2 years 24/7, are you deaf?, not just mine but all of my customers, and all are as good now as the day they were built. As for the Perkinelmer VTL5C3 lasting only 41 days, you are scare mongering, if you use them as I have outlined, the life should be as long as my units, which so far is 17500 hrs and still going strong.
As for all your negative comments, it's bizzare that someone thinks they can give ANY constructive input when they have not even listened to or built one, and who admits they listen to oxidized pots that are over 20 years old.
As for all your negative comments, it's bizzare that someone thinks they can give ANY constructive input when they have not even listened to or built one, and who admits they listen to oxidized pots that are over 20 years old.
Terry Demol said:
Sorry Terry, but I have a short fuse sometimes.
You asked in your PM to me.
[Private mail quote removed by moderator]
Ok, time to shoot oneself in the foot, the company I deal with is Silonex of Canada the units I use are the NSL-32SRS (sorted)
There is no published life expectancy on the units I am using, therefore I presume they could be indefinite.
I have had no degradation after 2 years of being on continuously, but mind you that the unit is left at the half volume position (normal listening), this is only half led power, this could be different if it is left at minimum or maximum when the leds are at full power, I have not tested it in these two positions for any length of time, maybe a day or two with no problems. The leds themselves would then have a certain life expectancy, how long I have no idea, could be years also. So far there has been not one failure in any of the units I have made.
Cheers George
Badge said:
Badge, if you look at the ruff circuit that I posted, it has one dual that can be 100k log or linear. You can use two duals one for each channel that would give you balance between channels, you could also de-adjust the 1k 25 turn trimpot to give you small range balance control, which is what I do, but it's only a couple of db each way.
Cheers George
The Lightspeed; An owners Opinion
I've been following this thread with interest and thought it might be time to add my 2 cents worth.
Firstly, I am not affiliated or related to the builder of the Lightspeed Attenuator, but I do own one and am a confirmed believer in its sonic superiority.
My path towards this unit has been long and varied. My system consists mainly of a pair of Infinity RS4.5's coupled to an Audio Research D250. Sources have varied over the years, but currently they are a Marantz CD17 KI and a Micromega Duo Dac. I would say this system is extremely musical but revealing - I'm into the music, not the equipment. I care more about how it sounds than how shiny it is or how many LED's I can see.
In terms of preamps, those that have passed through are as follows, as near as I can remember, but probably more; Phase Linear 4000, Bryston BP25, Dynaco Pat 5 and Pas 3 (modded), McCormac Micro Line Drive, Whatmough Passive, NAD 1100 (modded), Kenwood KC-1, Accuphase E-202, AV Light Surround Amp/Processor/Preamp, Pioneer Spec 1, Avantic etc etc
I by no means claim anything approaching "Golden Ear" status, but I do know what I like to hear and I believe I can recognise it when I hear it.
A friend recommended the Lightspeed after an afternoon of listening to his system. I liked what he was trying to achieve in terms of a true "Holographic" sound, using some rare Q-Sound Albums as a benchmark. The resulting improvements with "normal" tracks, once the system was tuned to the Q-Sound, were impressive indeed. Anyway, he mentioned the Lightspeed as a Preamp worth investigating. Following several long discussions with the builder, I placed my order. At approx. $550 AUD, it was and still is, an absolute no brainer.
I have now been using it for over 2 months, long enough to form an opinion, I believe and long enough to assess its merits. The sound is neutral in the extreme and if there are any enhancements or coloration at all, they are in the area of sound field extension and depth, but not at the expense of clarity and "musicality", if I can insert such an 'oft used and abused term here. One mans musicality may well be another’s ear bleed in my experience. Suffice to say that I like to hear everything that was recorded, I like to hear all the detail present, but not thrust at me so that it overpowers the "feel" of the recording. Basically, like a large majority I suspect, I like to have my cake and eat it too - a "system for all seasons" if you will.
The Lightspeed distinguished itself within 10 minutes of connection. I wont say I was awe-struck, or bowled over, or any of the usual Audio Superlatives that seem to fly thick and fast when a change for the better is heard in someone’s system. I guess the most noticeable thing for me was that the whole system sounded much more coherent, placement of both vocals and instruments were impeccable, with a true widening and deepening of the soundstage. Yes, I did hear things on some of my reference discs that I had not noticed before at a lower listening level than previously, always a good sign in my opinion. Bass was slightly sharper, especially in the leading edge of percussion instruments, which is apparently a Lightspeed trademark. Vocals, especially female, were presented with a silky lushness (Sorry for the superlative, it snuck in on me!) that let me hear all the sibilants along with each intake of breath from Norah Jones. Decay was excellent, with piano especially, hanging after being struck and then wisping away into a lovely black space between the sounds.
As you can probably guess, I like my Lightspeed, I like it a lot. Quite simply, it's wiped the floor with everything I've heard to date in my system. I now discover that it is being used in systems that cost considerably more than my first house, and is being used regularly and happily. Not that this means much to me, but it's nice to be in such illustrious company, if only by proxy!
To those who doubt its credentials, based on whatever notions of theory or practice they may have, all I can say is this: Don’t criticise until you've tried it and at the current price, you'd be crazy not to give it a go!
I've been following this thread with interest and thought it might be time to add my 2 cents worth.
Firstly, I am not affiliated or related to the builder of the Lightspeed Attenuator, but I do own one and am a confirmed believer in its sonic superiority.
My path towards this unit has been long and varied. My system consists mainly of a pair of Infinity RS4.5's coupled to an Audio Research D250. Sources have varied over the years, but currently they are a Marantz CD17 KI and a Micromega Duo Dac. I would say this system is extremely musical but revealing - I'm into the music, not the equipment. I care more about how it sounds than how shiny it is or how many LED's I can see.
In terms of preamps, those that have passed through are as follows, as near as I can remember, but probably more; Phase Linear 4000, Bryston BP25, Dynaco Pat 5 and Pas 3 (modded), McCormac Micro Line Drive, Whatmough Passive, NAD 1100 (modded), Kenwood KC-1, Accuphase E-202, AV Light Surround Amp/Processor/Preamp, Pioneer Spec 1, Avantic etc etc
I by no means claim anything approaching "Golden Ear" status, but I do know what I like to hear and I believe I can recognise it when I hear it.
A friend recommended the Lightspeed after an afternoon of listening to his system. I liked what he was trying to achieve in terms of a true "Holographic" sound, using some rare Q-Sound Albums as a benchmark. The resulting improvements with "normal" tracks, once the system was tuned to the Q-Sound, were impressive indeed. Anyway, he mentioned the Lightspeed as a Preamp worth investigating. Following several long discussions with the builder, I placed my order. At approx. $550 AUD, it was and still is, an absolute no brainer.
I have now been using it for over 2 months, long enough to form an opinion, I believe and long enough to assess its merits. The sound is neutral in the extreme and if there are any enhancements or coloration at all, they are in the area of sound field extension and depth, but not at the expense of clarity and "musicality", if I can insert such an 'oft used and abused term here. One mans musicality may well be another’s ear bleed in my experience. Suffice to say that I like to hear everything that was recorded, I like to hear all the detail present, but not thrust at me so that it overpowers the "feel" of the recording. Basically, like a large majority I suspect, I like to have my cake and eat it too - a "system for all seasons" if you will.
The Lightspeed distinguished itself within 10 minutes of connection. I wont say I was awe-struck, or bowled over, or any of the usual Audio Superlatives that seem to fly thick and fast when a change for the better is heard in someone’s system. I guess the most noticeable thing for me was that the whole system sounded much more coherent, placement of both vocals and instruments were impeccable, with a true widening and deepening of the soundstage. Yes, I did hear things on some of my reference discs that I had not noticed before at a lower listening level than previously, always a good sign in my opinion. Bass was slightly sharper, especially in the leading edge of percussion instruments, which is apparently a Lightspeed trademark. Vocals, especially female, were presented with a silky lushness (Sorry for the superlative, it snuck in on me!) that let me hear all the sibilants along with each intake of breath from Norah Jones. Decay was excellent, with piano especially, hanging after being struck and then wisping away into a lovely black space between the sounds.
As you can probably guess, I like my Lightspeed, I like it a lot. Quite simply, it's wiped the floor with everything I've heard to date in my system. I now discover that it is being used in systems that cost considerably more than my first house, and is being used regularly and happily. Not that this means much to me, but it's nice to be in such illustrious company, if only by proxy!
To those who doubt its credentials, based on whatever notions of theory or practice they may have, all I can say is this: Don’t criticise until you've tried it and at the current price, you'd be crazy not to give it a go!
Thanks for the glowing recomendation Audionutz, It's the type of explanation to the sound I would have liked to have posted, except it sounds a bit biased coming from the designer, so I had to temper my thoughts.
I hope that this will give some of the DIY'ers on this forum the confidence to build one for themselves, as I also beleive that it sounds very special, to the point of saying to one self that all other devices active or passive sound flawed in some way when listening to one, it's instantly reconizable.
The parts/nice case should be around the $150-$200aus mark and about a day to build, also I double regulate, down to 12v first then again regulate to 5v for the led power supply, it's important to get the this supply super smooth and stable and isolated as much as possible. A scope and sigal generator is handy to do the calibration 100%, though it can be done close enough by ear. Happy building.
Cheers George
I hope that this will give some of the DIY'ers on this forum the confidence to build one for themselves, as I also beleive that it sounds very special, to the point of saying to one self that all other devices active or passive sound flawed in some way when listening to one, it's instantly reconizable.
The parts/nice case should be around the $150-$200aus mark and about a day to build, also I double regulate, down to 12v first then again regulate to 5v for the led power supply, it's important to get the this supply super smooth and stable and isolated as much as possible. A scope and sigal generator is handy to do the calibration 100%, though it can be done close enough by ear. Happy building.
Cheers George
Audionutz,
Interesting! Can you please clarify - are you using the attenuator as a passive volume control or is it part of an active preamp, and/or did you insert it directly in place of an existing attenuator within an existing circuit, if so what was the original attenuator? Many thanks.
Tim.
Interesting! Can you please clarify - are you using the attenuator as a passive volume control or is it part of an active preamp, and/or did you insert it directly in place of an existing attenuator within an existing circuit, if so what was the original attenuator? Many thanks.
Tim.
wboyd said:
I would Wayne, but the ones that are made for customers, all have potted circuitry, therefore you can'nt see anything but cubes of of potting mix.
What I can do the next time I have it open is take photos of my own prototype one which is not potted, though it's not as neat on the eye as the others and the case is ordinary, but you'll get the drift of the layout.
Cheers George