Grannyring: I've noticed a great dependence on cable length.
Because of my set up, I have been running 2m Mogami cables out of the LSA to my rm10 and 1/2m Soundsilver sextopia into the LSA from my Allnic phonostage. They are both low capacitance so I thought I'd be ok.
Bored last week, so I moved the LSA closer to the amp so I could use the shorter cable (I used the longer cable to connect stage to LSA). Big difference! For the better, I think, but that's besides the point. I've now purchased longer speaker cables so I can try short IC's for both the input and output. |
Glad to here their a few more of us "dealers" out there. I was getting a little worried George wasn't building a large enough network to push product out the door to the masses:) |
Batalok, how long are your cables now and what brand? Just curious as I did not realize a cable could make such a big difference with this passive. Also curious what was done to your SS amp to help it work so well with the LS.
Thanks much. |
09-27-11: Acuscott
"...if you can afford a very epxensive pre-amp, then trying out this little $470 number as an experiment won't hurt the purse strings."
Precisely. It is indusputably worth auditioning and deciding for yourself if it does the trick in your setup - you may be more than pleasantly surprised. |
Sorry. I posted twice because the first didn't post right away. |
Are you guys dealers for LSA? :) |
This preamp simply, "isn't there". Ridiculously good. Ridiculously cheap. |
I have been using the LSA for a few months now with Coincident Frankensteins.
It replaced the Coincident Statement linestage which I really loved. I was lucky to reach out to Tony (clio09) when I saw he lived in the same town. I heard it in his system and for $470.00 decided to give it a try. As others have said it is flawless and is like having a direct connection from source to amps. I do have a system that meets the requirements- short interconnects etc. I have no problem with those that love active preamps, but for this price I think everyone should try the LSA. Thanks Tony!
George |
This preamp simply, "isn't there". I just shake me head at all of the ridiculously overpriced preamps out there after hearing this thing. |
I've owned one for years since i first saw it reviewed in 'audiophile'. It performs flawlessly and i would suggest less is more in these preamp circumstances. I have also owned the 'promethius' pre-amp and found that volume attenuators do a great job. If you must have an expensive pre-amp because you trust your wallet more than your ears then so be it. But if you can afford a very epxensive pre-amp, then trying out this little $470 number as an experiment won't hurt the purse strings. |
I've been using my lsa with ss monoblocks. In the beginning the lsa was polite, missing some dynamics. But I have changed the whole thing, other cables (shorter and different brand), I have modified a bit the poweramps (by somebody, a wizard). The lsa "sounds" terrific now! Dynamics? Yes! Polite? No way. All in all te lsa "sounds" as it should be, no other (?) preamp in the 15k pricerange (and maybe above) comes in the neighbourhood imho. But George could you make a remote control.....?
batalok. |
I have had my LS now for over 2 years and can thoroughly recommend it for its clear, transparent sound. I use both integrates and pre- amps and since buying the LS, my favourite pre being the Melody 1688 has sat in its box due to non use. I sometimes tend to have short listening sessions and warming up a tube pre is inconvenient.
The LS having only one set of inputs hasnt been a hassle as I use a multiple input phono stage but when I do need to change source say to CD its a little hassle unpluging and repluging new interconnects. For the price differential compared to a full blown multi source pre that sounds as good, its not a hassle at all.
George, if you made a dual/multi source LS then the world would be your oyster! cheers Michael |
If Teajay asked that of Paul I certainly missed it too. Not sure why it's even logical to ask of either of us. In any case I have no business relationship with George.
I'm not attempting to design and sell tube amps, I am actually doing it, preamps too, and step-up transformers for MC cartridges. How that factors in here I'm really not sure. However, per Audiogon rules I disclose my business affiliations when required. |
Don't mean to suggest with an amp with less than 100kohm input impedance, rather that would be my personal pridelection - I'm sure Goerge would point out that 47kohm and up should work fine. Of course you would not have any tubes in the chain and I would only use a SS amp with a tube preamp - something always seems to be missing when there are no tubes involved - I don't like it nearly as much. |
Teajay asked me that? That's odd - missed it. I use to think this site was mostly enthusiasts that liked blabbering to each other, but perhaps there are more commercial interests lurking in the woods that I care to think - nothing wrong with that if there is full disclosure.
As far as SS, I never tried it, and unless it was a 100kohm impedance load, I proabaly would not bother, something like the First Watt Alpeh J might do well, but for the most part, I see this as a tube amp device, though I imagine it has been used with SS and like Drubin some of them have found it perfectly suitable.
Disclosure: I paid full price for my LSA. |
I've been using the LSA with a Spectron Musician for the past couple of months and I'm very very pleased with the results. |
Not helping anyone at this point Tony. Just curious. Do you have any current or planned business relationship with George? Teajay asked that of Paul above and it is logical to ask the same of you. I know you are now attempting to design and sell tube amps now. Correct?
No LSA users with feedback on its performance with SS amplification? |
Was your S&B TVC a DIY job, looks nice. If so, have you considered trying a Slagle AVC? |
They have a term for what this has become....... "Circle-jerk" |
Has anyone heard the Troll 2B MKIII yet? |
What doesn't make sense Andrew?
Seems like it made sense to Al who replied that my methods reinforced the meaningfulness of my tests. I as well as many others around here respect his opinion.
Have you tried these tests yourself?
I sense you're about to start helping your "friends" again;) |
That is an interesting experiment Tony. I wonder what the technical explanation would be for that finding? It does not make sense.
Can anyone else describe their experiences with the LSA and SS amplification? I am still wondering the flat sound staging and what that is a byproduct of? |
Agreed, Anthony. That certainly reinforces the meaningfulness of the experiments you cited. This Jensen paper may be of interest to others who are following this thread. It explains why unbalanced interfaces between components can be prone to both low frequency hum and high frequency buzz, resulting from ground loop effects. Best regards, -- Al |
Al - agree with your point on ground loops, especially if the resulting noise is 60Hz hum. That is why if I suspect a ground loop I use the Jensen plugs to determine the component that is responsible. As I suspect you know, as you are familiar with Jensen products, this would be a good test method. |
09-22-11: Clio09
In my conversations with some designers the indication was that active preamps are responsible for a larger source of the noise in ones system than amps (assumption is we are talking similar designed equipment).... Adding any passive preamp I own (a TVC and the LSA) to the chain and then shorting the inputs on the preamp the noise level does not change (regardless of volume level). I can't say that for active tubed preamps (mine and other's systems), especially those that use tubes. Interesting, Anthony. I would add the thought, though, that the increase in noise that occurs with an active preamp could often be due in part to ground loop effects occurring between the active preamp and the amp, especially if the interface is unbalanced. To the extent that may be the case, a dilemma would arise, both philosophically and technically, as to which component is really responsible. Paul, thanks for your comment. Best regards, -- Al |
I have talked to two other designers of pre-amps who disagree with the fundamental premise behind the superiority of light-based volume controls. That does not make them right, but the gospel according to George is just that. Gospel to some and apocrypha to others. I've talked to some notable designers as well, including Roger Modjeski, whose word I will take as Gospel on many topics, but not this one. Not that he was not correct on a generic level about issues with LDRs. These are things that have been said before by others more knowledgeable than most around here and can be referenced on the DIY site. So nothing new there. I think what many miss is what George does to eliminate the main criticism of LDRs which is the issue of drifting. It is said that when ones work is copied it should be considered a form of flattery. Obviously some serious preamp manufacturers have found enough in George's work to copy it. I trust he is flattered. Regarding the paradigm shift. I for one have tried both and prefer having tube amps to tube preamps (although I will be digressing a bit by the end of the year). In my conversations with some designers the indication was that active preamps are responsible for a larger source of the noise in ones system than amps (assumption is we are talking similar designed equipment). Case in point at least in my system and others that have allowed me to do this simple test. Using shorting plugs on the inputs of my amps I cannot hear any noise (with my ear to the drivers) coming from my Music Reference amps (both sets). With my Atma-Sphere amps I get a minute level of noise from the tweeter. Adding any passive preamp I own (a TVC and the LSA) to the chain and then shorting the inputs on the preamp the noise level does not change (regardless of volume level). I can't say that for active tubed preamps (mine and other's systems), especially those that use tubes. There have been cases as well with noisy amps when I have done these tests outside my system, so that just adds to the noise floor in most cases. Also, from the perspective of the preamp in the chain, I agree with Ralph and his opinions of the volume control. It is nearly always the weakest link in a preamp design and will be responsible for sound deterioration. The LSA and some other very expensive switches will eliminate or minimize this, but even in some expensive preamps you get nothing more than an Alps pot. |
09-21-11: Teajay
Hi Unsound,
One of the oldest forms of knavery in a debate is to share very nasty implied information by saying that it was proposed by someone else, not the speaker, to get the dig in and than avoid the heat from the audience.
If a desinger is not using LDR, I would be surprised that they would argue for the superiority of LDR. Which does not mean the an LDR is better, but they would have little incentive to suggest that it is, even if it were.
I'm glad Al joined in, I always learn something from him. |
Not sure if diode effect theory drove George's design or the design was in search of a theory to explain its performance. It does seem he is doing something right, as others like Dartzeel deploy this approach in their active linestages where it serves as an attenuator in place of an ALPs, DACT, TKD, etc. |
Thanks Al. Your elucidation of the "diode effect" was helpful and confirmed some of my suspicions.
"All active circuits produce distortion/colouration whether they have no gain or unity gain." Can you be more specific? And what about amps? Do I need to revert back to the straight wire with gain?
I have talked to two other designers of pre-amps who disagree with the fundamental premise behind the superiority of light-based volume controls. That does not make them right, but the gospel according to George is just that. Gospel to some and apocrypha to others. We need more detailed feedback from actual engineers who make this stuff. Things are much more complex than we want to admit. I know that is not going to happen for reasons stated above.
If you were to rank system components in terms of importance, where would the volume control be?
If this is a paradigm shift, it appears to be away from tubed pre + SS amps to passive pre + tube amps. The "distortion" remains. The villain has just changed clothes....
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Hi Paul,
Yes, I certainly don't question that, assuming there are no significant tradeoffs in the "no contact" approach. As I indicated, what I was questioning was simply the explanation that I quoted.
Best regards,
-- Al |
Al, but we do know that contact quality is important[?], so would "no contact" have to be better? for whatever reason or theory? |
The (diode thingy) "diode effect" is bought around by very fast music transients from the source, CDP or phono, which can be in the order of 100's of volts per micro seconds (volts per uS) these happen as the name implies in micro seconds. While I have no reason to doubt the audibility of diode effects that may occur with many volume controls, I would respectfully point out that this explanation strikes me as fundamentally flawed. For line-level amplitudes, swings occurring at rates of 100's of volts per microsecond would represent spectral components (frequencies) at several tens of MHz. No source material and no source component will provide signal frequencies remotely approaching those rates. Not to mention that the amplifier, the speakers, and our ears would not respond to them even if they were somehow present. Regards, -- Al |
Love the DIY community, unfortuantely, I can only be an observer:)
What I found interesting at the start of the Warpspeed thread was the identification of a few "problems" with the LSA and attempt to improve upon the LSA:
-the inability to adjust to complete silence
-on low/high volume level settings, power levels on the LEDs endanger/shorten/toast the life out of the optocouplers
-the need to improve the power delivery to the optocouplers
-the need to improve on quality of the volume adjustment pot
-the Lightspeed, simple as it is, still has a number of variables/design factors that affect performance
How many of these are valid but not too relevant or important, valid and relevant but insurmontable due to a brick wall and sonic price to pay for addressing the issue, invalid (are the LEDs really in danger)? |
Ok some normal hifi speak for a change, I never been a big fan of balanced as 90% of the time to make them balanced a lot of the equipment manufacturers just bundle in more opamps into the single path to make it balanced input or output, very few are true balanced and discrete all the way through, you need to see the circuit diagram to find this out. Even the advantage of it does nothing for me, it's just so I'd be able to run 20mt interconnects with good noise figures. In the end most hi end poweramps speaker outputs are + and ground, single ended again.
I have tried doing balanced Lightspeeds quite a few times and even when double quad ldr's are matched perfectly they go out of calibration after just a few hours sometimes days because they are exponentially more critical to temp drift. And it is exponentially harder to match double mathed quads for balanced as it is single matched quads for single ended.
It can be done with sensors that would measure a test tone before each listening session and then do an auto calibrate circuit, but that then takes them away from being a matched set with the same i/o impedances for each channel, they would get wildly different readings and therefore each channel will sound slightly different to the other at different levels. Or you could do a feedback type arrangement then your asking for more crap in the signal path and making them active and creating distortions /colourations.
After one and a half year of developing Wapo seams to have hit a brick wall with his on diy, http://www.diyaudio.com/forums/analog-line-level/170381-precision-led-ldr-based-attenuator-15.html#post2687081
what I presented to them is the way it is, with development going back to 1974 in all sorts of formats, but they love to tinker, and good on them, this is how man reached the moon, but it's sad to see them as he said "This project has hit what appears to be an insurmountable brick wall."
Cheers George |
That is precisely what I do when I am not interested in a thread, ignore it. BENT was good, LSA was better in my system. But it is true, the BENT offers much more flexibility, but that was not a priority for me with a single source and short IC to amp, if it were the BENT would be at the top of my list for a passive, especially the version with Slagle auto former, even better than the S&B, at least to my ears. At this point, while I love the LSA, what is interesting is the new approaches taken, especially as the DIY tinkering community pursues new forms of passive forms of attenuation. Though for ergonomics, ease of use, and input/output flexibility, the BENT was heck of an excellent passive preamp. |
I for one would love to see this thread die already. I've followed it on and off from the sidelines for the last 15 months and for the most part it's little more than a three way conversation among like minded audiophiles... At one point I even suggested to George that he start his own forum, but as he said it would distract him from surfing. cool.
Here's my take, if anyone cares. Even if the LSA is the best, I'll never buy it. It's just to restricting in the real word. I need the flexibility offered by full function preamps, both tube and passives.
I've lived for years with a John Chapman, Bent Audio NOH. It's a passive similar to the Music First and based on the same S&B transformers. (Mine are copper.). It has 4 sets of RCA inputs and 2 xlr inputs, it outputs 2 sets of either single ended or balanced feeds, sports 6db of gain, has flooring grounds, etc.... I run 20 foot interconnects to mono blocks and a sub. Short interconnects and one input - no way.
I've also lived with a great dual mono tube preamp that offers similar flexibility.
I guess since this tread won't go away I will. |
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Not going through, don't know why. Google warpspeed attenuator you should find wajonaudio a few links down. |
http://wajonaudio.webs.com/GET%20THE%20PERFORMANCE%20of%20a%20$20k%20PRE-AMP%20for%20$200.html |
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you might find this interesting
http://wajonaudio.webs.com/GET%20THE%20PERFORMANCE%20of%20a%20$20k%20PRE-AMP%20for%20$200.html |
Regarding the question on the diode effect. For those that missed it or don't recall it George explains it as follows: The (diode thingy) "diode effect" is bought around by very fast music transients from the source, CDP or phono, which can be in the order of 100's of volts per micro seconds (volts per uS) these happen as the name implies in micro seconds.
When we view a static (constant) 1k-10k square waves on an ocilloscope all looks fairly fine going through a good pot (Alps Bournes ect).But it's when you pulse the waves at micro seconds (transients) an then store it on a very good super fast digital storage ocilloscope play the micro second pulses back frozen in time, and magnify the corners of the waves it's then you see the ringing/occilations effect of the light wiper contact on the conductive track of the pot, (I have named it for want of a better word, "dynamic contact bounce")It's the wiper being ever so slightly bounced on the track.
When pressure is applied to this wiper (with in my case a wooden skewer) so the wiper presses down hard down on the conductive track, the ringing occilations stop when doing the same test. When a soldered resistor is in place of the pot it's not there either, when a Lightspeed Attenuator is in place of the pot it also is not there either.All pots no matter how good bounce to a certain degree this is why they all sound different, they are all fundamentially flawed. The diode effect that George references and that the LSA eliminates is clearly something designers of some well known preamps understand and can hear. Here is a quote from one: Having done some audition in this regard (we 'switched', if you will pardon the pun, to our custom Shallco part about 15 years ago as a result of some of these auditions), the difference in contacts that George is describing above is clearly audible.
Its my opinion that the volume control is what shoots many preamps down (especially preamps with remote control) before they can even get off the runway. One of the consequences is that the majority of line stage technologies are in a deplorable state- I don't fault anyone for thinking that a passive might be better. FWIW - The custom Shallco switch referenced above is used in his top of the line preamp that uses gold contacts, with a double-spring-loaded wiper. Highly superior and much more costly compared to other switches. The designer also had this to say about the LSA: I had the opportunity to compare the Lightspeed against one of our own preamps and I have to say it was the most neutral passive I have heard. Anybody want to take a guess at who it is? I doubt anyone will question his knowledge on the subject. |
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Agears I hope I did not say mine was better than yours. Even musicians don't agree on sound. But that it is my perspective. I haven't even speculated in this thread as to the reason why, I think I know the simple answer, it is the 'why' in every other situation that causes something to be closest to the original. Anyway I thought my perspective would help someone looking at this thread or LSA for a view. I appreciate others view. We can learn something if we contribute. So George, Pub, Clio09, Atmasphere, Fiddler, Tvad, Grannyring and others thank you for some good information. |
AGREE!! And, what is the Warpspeed??? |
George,
You, I, and your tube gurus will just have to agree to disagree on this one. I think there could be more to this than we know and if so it may give you and some of the tube gurus the information needed to fully understand the circuit design. However, I'm not going to waste Masa Tsuda's time on this any longer given that he is not prone to be part of a public debate.
Suffice it to say as I have stated before I believe Masa Tsuda's specifications for output impedance and can verify that from my own personal use of the CF-080 the tube sockets hold the tube pins tightly and there is no reason for concern that they would fall out. The purpose of the roll bars is to protect the tubes from being banged up against something.
I consider both you and Masa very competent designers who have different approaches to achieving specified goals for your respective products. Each of you also have very different personalities. Like I said in a previous thread, what we probably have is a failure to communicate. It's obvious your personality rubs some people the wrong way. For me, that is not an issue, I can handle that. Others, well we know how they react. I agree that one in particular would like to see this thread go away and their behavior shows it. Enough said on that subject.
You have been very generous with sharing your ideas and helping people like me learn about a new product that has enhanced my system. Masa Tsuda has done that as well, and in the process become a friend. Like I also said before, if I ever get down under I would certainly enjoy quaffing a few beers with you.
Let's get this thread back on course and continue the discussion on the LSA. Also I'd like to discuss this Warpspeed if you are inclined. Seems like another interesting approach. |
Why is a preference for distortion and/or coloration utter nonsense? What is wrong with prefering it. Distortion is measureable, not a subjective gremlin, what if you also happen to like the the piece with more distortion? How many folks have loved CJ equipment over the years knowing full well it was colored, but in a very satisfying way.
What I do suspect is that the signal from the source output is closer to the signal coming from the LSA output than if the signal must go through an active linestage. One might differ on whether this is what we should want, or what we should prefer, but I think (not 100% sure) that this would be measurably the fact of the matter, measurably truer to the source (meaning the CD player output, not the live performance). If the active linestage alters the relationship between the two (source ouput/preamp output) it is inarguably a distortion (and not true or part of what is exist in the signal at the source output connection) -- which you might very well prefer.
Carver's Hologram generator sure did unflatten a soundstage, but it was no part the recording, it was an effect, an artifact created by altering the source signal and delivering something different to the amp. And it may be lovely, enjoyable, pleasant, wondeful, magical, mysterious, etc. - but whatever it is, I just don't see how it can be said to true to the source, true in a measureable and meaningful way - assuming what we measure is relevant. |
Unsound,
I don`t believe Mr.Tsuda, Nelson Pass, Kevin Hayes(VAC) Israel Blume(coincident) just to name a few very accomplished designers of active linestages would come on a public forum and mock/dismiss someone else`s work.
There`s such a thing as decorum, class and restraint that would prevent them from such smug and arrogant behavior.
I`m sure these men believe in their ideas and products as much as george.
I don`t believe they would put down those who after auditioning their components and then decidimg to choose another brand,they would`nt blame the listener`s system or attribute it to an inability to hear(the epitome of patronizing attitude).
Following this thread for a while, my take is that for some the Lightspeed will be ideal and make them very content.
Those who have taken the time and effort to audition this component and then selected something more to their liking don`t need to be subjected to, well you just prefer distortion and colorations. Utter nonsense. |
