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've light loaded the RM10s and RM9s and prefer the 8 ohm tpa with the Merlins - in part, this must be because the VSMs are not speakers seaking more damping from the amp, so it might be very speaker dependent. There is a thread on Audio Circle like you mention. Might be an interesting question as a separate thread, that is the whole light loading approach with amps that have differrent rated taps.
Light loading is supposed to make the amp more linear, with significantly less distortion, and more headroom. Yes, there will be less power (negligible in my case), but the damping factor doubles. My speakers are rated between 8 and 12 ohms, so while I've used the 8 ohm taps on the amp, I'm not sure I'm getting the same benefit of light loading as others who might be using the 4 ohm tap for their 8 ohm speakers. Perhaps using the 4 ohm taps would be better. I'll go over to Audio Circle and post the question over there.
Do you think the 12ohm nominal benefits you with light loading because you lose less power output? I think your "light loading" with the 8 ohm tap with your speakers.
Wilsynet, I agree with everything you just said, and the Merlins, like the Zus are very benign loads, and efficient enough for 35 watts. I think, not always sure, that my preferred system is the all Atma-sphere rig, but the LSA with my RM10s and RM9 SEs, are might fine, can't really get myself to sell any of them. In my system, I preferred the Atma M60s and MR RM9 Special Editions to my CAT JL2s which I thought were just about as good as amps could be, certainly the CATs can handle a wider array of speaker loads than the Atma-sphere, but those RM9 SEs put out 162 watts into 8 Ohm and 200 into 4ohms, that is alot of tube power - if I could only own one amp for all seasons it would proabably be the RM9 (with my LSA).
I do agree with the review. It's a well balanced amplifier, does everything well, some things very well and nothing at all poorly. It is very, very good with the LSA.
Regarding speed, it's fast but not fast like the Atma-sphere S-30. On the other hand, to these ears, it has more density than the S-30.
The 6moons review notes that the amp is not as good with complex music at scale, I have no such observation, although my speaker load is particularly benign and efficient.
I would say the RM10 is quite neutral and fast with the LSA, as described in the 6moons review. But, use it with a 6sn7 based active preamp, and use RCA 6sn7s and you might have a "tubier" flavor, but the amp itself seems neutral, with tube bloom and soundstaging that only tubes seems to do compared with even the best SS. The RM9 with EL34s is a slightly darker flavor, but I think Roger has always designed with neutrality in ,ind and nothing overtly tubey in the CJ/Cary vain. I am always amazed by the RM10. I wonder what the mono setup wpould sound like - I suspect Roger would say the stereo version is better if you don't need the extra power (35 versus 70 watts).
I agree with the assessment, although some tube rolling could change that. Pubul57 might be able to share more on that as I believe he has done some tube swapping with the amp. I use the stock tubes as supplied by Roger and the way Srajan describes it is how I hear it. FWIW and if IIRC, Roger designed the RM-10 using Quad 57 speakers with it for his listening tests. There are some other interesting design characteristics about the amp that fly in the face of typical amp designs and how we audiophiles associate various sound qualities with them.
Tvad, if you're interested in hearing the RM-10 let me know. I'm not using mine at the moment. If possible I'd like to compare the RM-10/LSA combo versus RM-10/VRE-1 combo.
Wilsynet, glad you were able to put together this combination. It is incredibly good for the money. I have about $1500 invested in my LSA and RM-10 MkII. That's tough to beat for SOTA sound.
I've been listening to the LSA with battery power supply for a while now. I would suggest to anyone that owns one to give it a try. The parts cost is less than $75 (here in the US anyway) and it's plug and play. Also, I've been using my LSA with the Atmasphere S-30. Now I'm tempted to break out the RM-10 again.
Wilsynet, I'm glad you gave it a try. By the way, Clio9 is also using the LSA with the RM10MKII. Not sure if this is the reason why, but one reason I felt the compulsion to try a passive was the Roger Modjeski (Music Reference)told me to use a passive, that no active could be better; though he was willing to build me a more traditional tube-buffered with or without gain. Well, you know Roger can buiild anything, and he loves selling tubes, yet this fella who knows a thing or two about audio insisted to go with a passive. Then I read Arthur Salvatore's comments on passive versus active. Well, I had to go about testing the concept and have had Placette, Goldpoint, BENT TVC and AVC, and Roger's Pot-in-a-Box - they all sounded excellent, these were not gradations of crap to great, they were all at least very good, and at the end of that path I came to the LSA which was the best of the lot IMHO and I'll say that in my system with ideal[?] impedance matches and ICs the LSA is the best passive preamp I have heard, and I suspect if your system well suited toward the passive approach the LSA will give you SOTA sound quality for $450 which is a good thing to know, especially if finance are an issue, combined with the RM10MKII I think that is just about as good as it gets IF 35 watts is enough power for your speakers, room, listening volume.
I decided to take Pubul57's lead. Using the Lightspeed Attenuator with the Music Reference RM-10 MkII. Sources are the db Audio Labs Tranquility SE DAC or the Ray Samuels Nighthawk phono stage.
I don't miss having an active preamp at all.
The sources have 50-60 ohm output impedance, and the amplifier has 100Kohms input impedance. I think with the right components and appropriate input and output impedances you won't miss an active preamp either.
"I too will be getting an opportunity to hear the LSA and compare it to my TRL Dude. That should be fun. More importantly, I will involve my non-audiophile, musician wife in a blinded listening test between the two and will report on her findings rather than mine." (Agear)
Agear, have you been able to do this comparison yet? looking forward to it.
CES is huge, think downtown Manhattan in rush hour. Proper planning can assure you get to see what you want, and potentially in off-peak hours. The rooms are good size and I find the set-up done properly can sound very good. It can be intimidating at first, but overall not so bad. IMO it will be proportionally worse space wise at RMAF on Saturday when you get the full impact of the outsiders and locals attending. The Venetian will be crowded, but there's more space to work with overall.
I think the jewel is THE SHOW. Last year it was at the Flamingo and was done very well IMO. You'll get more boutique manufacturers, less crowds, and can cover more ground in less time. The kicker would be if the NSF exhibit room is on for this year. An audiophile(s?) rents the space and provides a funky lounge atmosphere (no pun) with adult beverages and music. Last year John DeVore had his speakers in the room and the rest of the system I believe was supplied by the sponsor(?). Played lots of vinyl too. THE SHOW is where Ralph sets up shop, as does Brian Cheney (VMPS), Audio Note, and a few other notables.
How does the atmosphere, no pun intended, and rooms compare at CES versus RMAF? RMAF is on of the best audio shows I have been to -- I use to go to the COMDEX shows in the old days, would not want to go through that again:)
If you're inclined to come out West you could sure stop by. Think CES/THE SHOW. Ralph will be in town as well. He's mentioned I should hear one of his preamps in my system with the S-30, especially using the balanced phono inputs. Maybe I can convince him to drop by too.
Well one thing for sure GR, you have the best amps in the world:) Do you use Speltz autoformers with the Sound Labs? For some reason, I'm not tempted to use the LSA with the Atma-sphere (M60s).
I do want my system to sound like the natural sound of an instrument or voice un-amplified electronically. A piano for example is the most difficult to get right. That is where I really miss the weight and scale on the LSA as well as large Orchestral works. Even Van the Man and other live events can and do sound great at the right venue. The PA comment does not always define the sound of live music as we know.
I hope to bring my 40 pound active, looks like an amplifier active, to someone's LSA friendly and smokin system soon.
Thanks all for the great thread of life here. Van the Man has the same hefty and full bodied voice on all of his last CD's recorded over the past 20 years or so. I simply don't get that or the 3D stage of the recording or live performance with the LSA as much as the Dude. But the Dude is that 1% that may in fact do it better! Ha!
Really, I do think my system is a best/great match for the LSA. My speakers are so very hard to drive with an impedence curve from a low of 2 ohms all the way up to 35 ohms in the bass. It is hard on my OTL amp! Fact is I need more power.
I would welcome the opportunity to bring my Dude over one of your home's with a great LSA matching system and do the A/B. I am most interested in your take away from that experience.
I don't care how hard you try, even if you put considerable investment ($$$$$) and built a custom dedicated room you would not get anywhere near true live sound. You stand a much better chance of getting the true essence of the recording, or at best something that meets your listening preferences and is pleasing. There's nothing wrong with that either. I've been in some really nice listening rooms too, but the replication of live sound (even on a live recording) is not what I hear. Great sound yes, live sound no.
Personally, if you want to replicate live sound go build/buy a studio, club, or music venue and book live performers. If you're going to do it then do it right.
I must say that when I come home after listening to a live jazz concert, natural acoustic, unamplified, I realize that if I had a $1,000,000 system, with a perfect room, and and 24/96 digital recordings, it would still never sound like real instruments in a real venue - in some ways it might even sound better, or be more pleasurable at home, but it never really feels like the real thing to me - but that is OK with me, I'm not going to find Coltrane or Mingus at the club down the road either.
I've been following this discussion with much interest, and I feel inclined to chime in. . .
There have been several comments about the goal of our systems (preamps here specifically) being to sound like the live event. Bill just commented above about hearing Van Morrison live, and feeling that the LSA doesn't provide that experience.
I submit that the role of our systems is to reproduce the recording, not the live event. If the recording doesn't contain the appropriate information or is of poor quality, then by default, if it reproduces the sound of the live event it's coloring the sound. If I happen to like that sound, that's okay but I'm not fooling myself into thinking it's an accurate reproduction of the recording. The question then becomes, "what does the recording actually sound like?".
I think the suggestion is that the LSA provides the best answer to that question, all things being equal.
Well said Pubul57. If I could just add to that, as I tell many customers, a direct connection between CDP (non tube) and Poweramp is the best/truest transfer of what is recorded on the disc. And the Lightspeed Attenuator comes the closest to that direct CDP (non tube) to poweramp connection.
If an active preamp sounds better than this, then it is the system that has a problem and needs the coulouration of the active preamp to band-aid fix that problem, it would be better to fix the problem than to cover it up.
Grannyring, "it is the recording my preamp has more fidelity to" - more fidelity than the LSA in your system? -- that is very possible. What seems impossible is that an active linestage could have more fidelity to the recording than a direct connection (with no impedance mismatches, and no ICs), I suspect that in your system, for some reason, you would hear a difference between the direct connection and the LSA connection because something is just not matching right - now, if it sounds the same then I just don't see how your preamp is truer to the recording; though I believe that Van Morrison live, in a large space, and amplified through a sound system is going to sound quite different than a studio recording or even a live feed from a live performance. The important thing is you have a preamp that you love and makes you happy; what it is all about.
Paul, I'll be attending the party for a little bit this year seeking out some folks to say hello. I'll be getting over to Del Frisco's Double Eagle Steakhouse as well. There's a bottle of Silver Oak Cabernet with my name on it courtesy of friend. Can't miss out on that.
Some good after hours events in the rooms too. Thom Mackris from Galibier Design (I use his Serac turn table) is doing some fun stuff. I'll be staying in the Concert Fidelity suite as their guest, so I'm sure we'll be keeping the music going a bit past 6pm. It should be a very well attended event.
Keep CES/THE SHOW in mind. If you've never been to it this is a great time too, although somewhat more exhausting than RMAF. We have a Del Frisco's here too:)
No, it is the recording my preamp has more fidelity to, not distortion etc... I have heard Van Morrison live on many an occasion and the weight and heft of his voice is missing on the LSA compared to the active.
Sorry, but them there are the simple facts in my system.
George, that is what I thought but being an E.E. ingnoramus I did not feel comfortable making that claim, or the my EMM Labs CDP seems to have a pretty well built power supply. I think that whatever it is that some prefer with active linestages (even when impedance matching, current, and gain is not a problem), and they have every right to feel that way, it is not something actually in the recording, but a distortion that might "feel" truer to some, but cannot be truer to the source in fact.
The argument of passive versus active may be as unwinnable (and it does not have to be "won") as the old SS/tubes argument, what I feel pretty comfortable saying however, is that in a well matched source, cable, amp environment, the LSA is the best passive volume control I have had in my system after trying all the major alternatives. In a different system setup than what I have, I might prefer a unity gain with buffer, or an active tube linestage.
10-11-10: Agear CDPs generally suck when driving amps directly due to a lack of current (not merely a function of output voltage as some have suggested above in this thread). Current, from my limited understanding, is needed to reproduce in particular lower frequency information. Agear
CDP's (not tube output ones) have lower output impedances and therefore and higher driving current ability into power amps than 99.9% of tube preamps.
The "Heather Test" has officially entered the Audiogon lexicon, and I suspect we all do it and rely on it from time to time:) Now, where did I put the Chianti....?
"What you should do Grannyring to see if the Dude is artificially giving depth, is what I preach all along, put your CDP straight into your poweramp (Bolero Test) no preamp. Put on a quite cd so you can then ascertain a good level of cd to play, then swap in the Lightspeed then your Dude and see which is closer to no preamp. The one that is, is the one that is truer to the source." George...
As I stated on the 9th, using the Bolero test to argue for a pre-amps' relative transparency or "trueness" is circular and flawed logic IMO. After rereading George's statement, the real burning question is not whether the Dude is adding an artifical depth but rather whether the LSA is simply not able to convey information that is inherent to the recording. CDPs generally suck when driving amps directly due to a lack of current (not merely a function of output voltage as some have suggested above in this thread). Current, from my limited understanding, is needed to reproduce in particular lower frequency information. When that is missing, soundstaging is effected among other things. Driving higher frequencies (tweeter) generally requires less current, and when done without proper representation of the lower frequency info, people often misinterpret this thin sound as "transparency." I myself have experienced that transitory illusion when playing direct. Ergo, a device which more closely mimics this phenomenon is not desirable IMO.
I am signing off. I will report back with results from the "Heather test." Some particulars you need to know about this particular test: I usually have to ply her with at least one glass of red wine in advance. A vintage Vera Neuman scarf (of her choosing) as a blindfold. 5-10 familiar tracks played at between 80-90 dB. Each single track will be played on each device and will be verbally labelled A + B. Just now, Heather giggled with glee when I informed her that a test has been named after her.
Yes the Burson is also discrete but with +6db of gain, but not DIY, and Nelson's is unity gain and I would say more transparent. As for running a single ended Lightspeed into a balanced amp, you could use something like these on the input of the Atma-Sphere's
George, aren't the Burson Audio buffers an FET design that does not use ICs? Their RCA version includes a volume control too. Curious as to why the balanced XLR version doesn't. Might have liked to the balanced XLR version give a spin with my Atma-Sphere amp.
Yes, Nelson Pass very kindly did get involved, and designed a nice direct coupled discrete (no yuk opamps) DIY buffer for the Lightspeed Attenuator, because some of his amps were 12k and 20k input impedance, and this made Lightspeed Attenuator match those low impedance amps correctly.
Clio09, Of course in LSA the series/shunt photoresistor IS the volume control. The knob that you twist merely controls the control. I'm suggesting that by adding a companion active buffer, the LDR control could be directly compared to a conventional volume control(e.g. potentiometer, stepped attenuator, etc.) independent of systems matching. Chances are good that an LSA buffered in this manner would come out ahead of most active preamps. And by switching off the buffer function you would know immediately whether the problem is a mismatch.
Interesting comment on the buffered approach Dave. I believe when John Chapman re-introduced the Tap-X with the Slagle autoformers the remote allowed you to choose from buffered or unbuffered (only on the multi-input models though). In his testing he said he couldn't distinguish a difference between the two, but his goal was obviously to allow a user to address impedance mismatches. The Truth preamp I wrote about in another thread uses photo cells and a buffered output. Output impedance is extremely low, something like 2 ohms. It supposedly can drive cables up to 30 ft. in length. It works nicely with my Atma-Sphere S-30, but as Pubul57 mentioned if you don't need the buffer, and my other amps don't, why add anything to the mix.
In this scenario the comparison of LSA to other preamps becomes more of a contest between volume controls-- which is a critical and oft-neglected determinant of a preamp's performance.
I agree we often forget the impact of the volume control in preamp designs. The concept of removing the volume control from the equation was what got me interested in the LSA to begin with. The LSA doesn't need a high quality volume control since the design eliminates the impact on its performance.
As George said June 14th, "The best sound you will get is to put your (CD DAC or Phono) directly into your power amps with a VERY quite CD track first, this is the most perfect "true to the source" sound you will get, and only the Lightspeed Attenuator is closest pre or passive to mimicking that sound." This description suggest the direct connection, where Bolero is simply used to keep from blowing out your speakers, and it appears to be George's view the standard for the most accurate transmission of the source signal to an amp (not a level test) - and in this case there is no impedance mismatch; I agree with Dgarretson that when there is and impedance mismatch, a buffered passive (or active) will likely perform better - As George has susggested and Arthur Salvatore and Roger Modjeski of Music Reference both said - but with good impedance matches the buffer option will not be as pure/good as truly passive. I do wish I had a Pass B1 to test in the system.
I don't think I will run the LSA with the Atma-amps no matter the season for they are designed to run with balanced connections, and they are not very sensitive - some gain in the preamp is needed. The LSA has made my Music Reference amps sound their best (the RM9 SE I preferred to my CAT JL2), but I still prefer the Atma amp cuz I don't think you can beat OTLs if your speakers work well with them - mine do.
Dream preamp - active tube line stage with low output impedance and variable gain settings, switchable to unity gain tube buffered output, or purely resistor passive - the LSA as volume control of course. Hmmm. I bet Modjeski could build one....
As George just stated, the Bolero test is a level test only, not a tool for system analysis. Grannyring got people excited with his description of the 2D sound staging of the LSA. What followed was philosophical posturing, semantics, and the infamous Bolero test...all attempts to rationalize his findings. His findings are his findings only, not gospel as he has already said.
Pubul57, I will await winter and your comparison of the LSA and Atma gear since you are straddling two worlds and are thus somewhat double minded. That report will have the same value (or close to) as my wife's description. The "Heather test."
Larkston_zinazpic, you are brilliant. You said something without saying anything.
"Amplifying the low-level stuff, stuff that might not get through (stage depth & other nuances) is important and not insignificant as we know. Is it possible a great active can get more of this information by way of design then a passive?"
When I was building a replacement analog stage for my Sony CDP, I compared an entirely passive solution that used silver step-up transformers directly from the voltage DAC to output, to the same transformers with the addition of an active battery-powered buffer. In each case the CDP output was connected to an Atma-Sphere MP-1 tube line stage. Going into that experiment I expected to hear sonic trade-offs, with the passive winning on treble resolution & overall sonic purity, and the active winning on dynamics and LF control. In actuality the hybrid buffered approach won on every point. As a result I opine that if the impedance match is anything less than perfect(and who really knows for certain what is perfect?), a passive would benefit by being equipped with an active buffer on an A/B switch. There are several simple & inexpensive buffer designs(including one contributed to the Lightspeed DIY thread by Nelson Pass)that will do justice to a top-quality passive. In this scenario the comparison of LSA to other preamps becomes more of a contest between volume controls-- which is a critical and oft-neglected determinant of a preamp's performance.
Bill, I'd certainly love to hear those Sound Labs in a good room set-up. I have heard them at audio shows and once at a local Chicago area dealers home. The latter was a very good experience, but not ideal IMO.
Your point you made in your other post is very clear to me, but I happen to agree with Pubul57 on this one. Six of one half a dozen of the other.
Pubul57 - Seems I have written pages :-) on this yet no understanding of my point? It may be impossible and that's OK!
A "direct connection" as you say, is as I say, just another STEREO SYSTEM and produces a sound of its own. Direct connection from CD player to amp is not, as another has stated here, the GOLD STANDARD, it is simply another way to hear music out of a stereo system. A CD player driving amps is still a stereo system that does or does not reproduce the voice or instrument accurately to the recording or live event. The END result (sound) of a system is the proof. I and others suggest a passive unit "can" or "sometimes" can, depending on the total system, fail to pass along the recording with a sound that is true to the source. This can also be true of an active unit.
Many folks far more educated then me on audio circuits and recording practices will wax poetically why DAC's/CD players etc.. are an insufficient means to pass along the signal to an amp with only a passive in the chain. Meaning the resulting sound may lack in areas as the system simply lacks the horsepower needed to convey the energy and space of live music and great recordings. I don't want to argue that and all the math and audio geek talk that goes with it. I do know what I hear however in my system. It is not added coloration; it is in fact hearing MORE of the recording as intended with my active in place.
One reason may be as simple as my active Dude preamp has all the lows, all the highs, all the transparency, and depth of field and soundstage width simply because it actually amplifies ALL that is there and does not mask as has been implied. Amplifying the low-level stuff, stuff that might not get through (stage depth & other nuances) is important and not insignificant as we know. Is it possible a great active can get more of this information by way of design then a passive? At least as much? Seems reasonable to me.
Just trying for us to see with a broader view that sweeping comments about one type of design being the GOLD STANDARD may be a little narrow?
I don't think there is any confusion about why "Bolero" is a recommended piece for trying a direct connection between CDP and amp.
Not sure I've hear an argument yet as to why a direct connection is not "the" standard for assessing the sound of a recording from a particular CDP as a source, to me it seems absolutely is the standard of what a recording sounds like unadulerate and uncolored by the use of a preamplifier; the LSA is about as close to that as you can get, and an active preamp, which one might prefer, in nevertheless an additive coloration not found in the source signal.
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