Lightspeed Attenuator - Best Preamp Ever?

George
Do I need to buy anything else other than the item in that link (eg power cable?). I will try one out.
Thanks

Yeah a few now have really liked the TeraDak power supply, good value for what you get $44!!!!, just the chassis would cost me that.
http://www.ab-system.hk/index.php?route=product/product&product_id=64

Good to see someone else likes DHT SE transmission tube amps, I managed to get the circuit for these, and built my own 805 mono blocks (40kg each) a few years ago just for mids and highs on my esl's
http://www.wavac-audio.jp/md805m_e.shtml

Cheers George

Well for me the differences were easy to pick up in my particular set up. Remember, my LSA components were placed inside my dac thus turning my dac into a dac with volume control. This eliminated the need for a set of ICs and RCA connectors. I also used some very good silver/gold solid core wire in cotton from Jupiter Condenser to wire the LSA board inside my dac.

I prefer the battery over the wall wart in my system finding it sounded more relaxed and engaging. Just wanted to listen more with the battery. The difference here was slight and some may like the linear wall wart better because it did seem a tad, just tad, more dynamic and upfront.

However the TeraDak supply simply put a big smile on my face immediately. It delivers the best of both the battery and linear wall wart and then some! I immediately heard more powerful and impactful bass. This was evident the moment the first song began playing. In addition, the music in general was more dynamic and alive. One final area of improvement that I found most noticeable was a blacker background with the instruments emerging with more realism, resolution, and sense of space and real estate between instruments. This was quite surprising to me and very fun to listen to. I really did not expect this result.

I use two amplifiers and both revealed the same improvement. An 845 DHT tube SET amp and a Lector VM200 hybrid amp that is direct coupled. Both work great with my set up and the LSA .

Hi Grannyring, good to see your still loving the Lightspeed Attenuator. It would be nice to get a "sound" difference comparison between the standard wall wart v battery v Teradak power supply.

As my a/b's with a group of golden ears showed differences when they knew which power supply was being used.
But were also inconclusive when asked in blind a/b tests with the same group, then they said the differences were too close to call.

Here is something very interesting that can explain why many say what they say about the Lightspeed Attenuator's superior transparency compare to volume control potentiometers used in most all commercial preamps, active or passive.

http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp-273.html#post4394156

Cheers George

I purchased the following power supply based on George's suggestion in this thread,

TeraDak TeraLink X1/X2 DC8.5V 1A + USB DC5V port Linear Power Supply

Well I think this little power supply is a must buy for the LS. I could not be more pleased with the results. I have the linear wall wart as well as a cheap battery supply and this TeraDak is far better in my rig.

Enjoying the music and just wanted to pass this on.

We've found that a buffer for the Lightspeed Attenuator is only needed if your amp is less than <33kohm input impedance or your source has a tube output stage with high 1kohm or more output impedance.

If your poweramp has an input impedance less than 33kohm, then this is the best solid state buffer we've heard so far with the Lightspeed. You do have to diy a little with a simple 15-0-15 power supply, case and rca's.
But it's a killer fet input, bi-polar output buffer at a stupid cheap price of $20.

http://www.ebay.com/itm/171436195085?ru=http%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_from%3DR40%26_sacat%3D0%26_nkw%3D171436195085%26_rdc%3D1

Cheers George

Agree with Marqmike; the Burson ab 160 adds nothing negative to the equation. Get one to try if you can find one.

Thanks Vyokyong
At times I use a Burson ab 160 with my LSA. It is a buffer that is exceptionally organic sounding. I wanted to say tube like but organic/natural sounding is more correct. They are not made anymore but sometimes available used. Now I may change out my internals. Thanks again

Hello,

As I confirm with Marqmike, I will give more impression.
I am still using LSA and very happy with LSA. After mod with pure silver wire and pure silver WBT RCA plug, the LSA provides very delicate micro nuance, better contrast of micro and macro dynamics, better transient and articulate bass. The treble is sparkling. The only concern is that you have to make sure that the electricity feed LSA is strong enough when LSA is run by battery power. If yours system sound is weak in dynamics, please check battery power first that it is strong or not. When battery power is weak, it makes your system sound no dynamics.

However now I plan to acquire Coincident Line Statement preamp. Because my system is not loud enough when music recorded with low gain is played. My system need more gain. It is not fault of LSA. Because the sound is not loud enough also when I connect front DAC directly to amp. I will give my review between Coincident Line Statement preamp verus LSA when I got Coincident Line Statement Pre-amp.

I have been living with my LSA for a couple of months now. It was bought to help improve the dynamics of my system. It has worked better than I hoped for. Not only have the transients improved greatly but the unexpected gain in fine detail and accuracy of the sound placement is indeed a pleasant surprise.
My system has been built up over a period of 20+ years, with the intention of getting the absolute best sound I can, while avoiding the trap of the law of diminishing returns, which is so common in hi-fi. This approach has resulted in an unconventional setup that sounds far better than the sum of components would suggest. It consists of:- Sony BDP-s580 blue ray---Musical Fidelity M1 DAC----LSA---Elliot Sound Products 4th order active crossover---Rotel RB 930AX for highs, Rotel RB991's for mids and lows---B&W matrix 801 s2's now running full active. All interconnects are standard Monster as is the speaker cabling, which has a double run for the bass to reduce voltage drop on large transients. The speakers sit on custom made lead filled stainless steel stands.
The LSA has been the last link added, with the $500 or so giving far more improvement than the price would suggest.

Sorry no, we have done it a few times, but without the electronic type/s of feedback that other single ended Lightspeed clones use, they will not stay in calibration over a long period of time, as the matching of the 8 x led/ldr's for balanced output is exponentially more critical than just quad matching for normal single ended.

We have found with a/b listening tests with numerous audiophiles, that these types of electronic matching feedbacks no matter which ones we designed, were detrimental to the sound quality of just doing the proper quad matching without feedback, even though it takes much time, labour and expense to do.
Forced matching seemed to have thinner bass and more etched highs, with a lack of body to the mids, when compared to the production normal Lighspeed Attenuator.


Cheers George

George,

Do you make a balanced version? What would that cost?

Yeah ditto, Grannyring back probs are a "b***h"

Get well soon George

Thanks Al and Swampwalker!

Bill (Grannyring), a strong +1 to Swampwalker's comments. Very glad the surgery, and less importantly the system, have had fine results.

Best,
-- Al

Hi Bill- Glad to hear that the surgery on your back and your system both went well. As long as it sounds good it is good! And with your back feeling better, well, I'd say you have made some very good decisions. Best wishes for a fast, full recovery!

Life has thrown me a curve ball that necessitated the selling off of my most expensive gear to pay for some specialized back surgery. The surgery was very, very expensive and cutting edge . It was not covered in large part by insurance. However, I still wanted a great sounding system. I just returned from surgery yesterday after a long week in LA where the surgery took place. Just two days after this special surgery I am doing very well and feel I spent my money wisely.

The LSA placed directly in my dac was the perfect answer. I am happy with the net result of my system and feel I spent my money wisely again.

I placed the LSA guts into a Yamamoto dac which feeds an Ultra Fi Monaco 845 DHT amp. The resulting music is resolute, musical, and very engaging. I could not be more pleased. Are there trade-offs in going from my active tube preamp/Aesthetix Romulus combo to the one box Yamamoto dac with internal LSA Attenuator? Well in audio there are always trade-offs. Without getting into all the Aphile differences I can certainly say that I am enjoying my music as much as ever. That is the bottom line.

I have a unit that I didnt buy directly from Tortuga, but it uses their board. I am extremely happy with it and did compare to the lightspeed. Very close performance, both are excellent.

Shakey

Wow!!!!!! I am speechless, over his post in this thread that I unsubscribed to!
Good work Grannyring, you've found the "Light" speed.

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1426779273&openflup&128&4#128

Thanks George

Roxy54: PM sent

Cheers George

What is the price? I looked at the website and it says to call for price.

05-05-15: Rob_j

So I thought I'd post a bit of feedback now that the LSA has had a couple of weeks of play to settle up.

My regular attenuator is a Townshend Allegri passive which retails for very many times what the LSA costs. Retail price is not a reliable indicator of performance as we know: just setting the scene.

I have to say that the LSA is simply astonishing. It is fluid, extended at the frequency extremes and has a lightning fast attack at the leading edge of notes, then a detailed and realistic decay. Instruments exist in their own space and are distinct from others. There's a quiet confidence to the sound, with a dark background seemingly devoid of interference/noise. No grain, silken and natural.

That's the thing: this really plays music rather than sounding like "good hifi". Music sounds real and involving.

The LSA seems equally happy with Hans Zimmers massive layering and soundstage as it is with Marcus Millers dynamic bass guitar, Army of Mushrooms's bonkers electronica or Jan Garbareks soprano sax. It all works.

In short: Well done George! Overall, the LSA bests the Townshend in my system.

Robert

First off Robert, I would like to thank you for your praise and great review of the Lightspeed Attenuator.

You are right in that it has extended range as it is dc coupled to almost infinity in speed, hence the name Lightspeed.

As for the dark background you mention, it has a far lower noise than any active preamp can be. This is why you get a perfect black background, which aids in greater dynamic range and space around the notes. There will be times you'll think your system is not switch on when your in-between tracks, or when the lead in of tracks have no music content yet.

As for your "No grain, silken and natural" comment, there are no "active preamp" component distortions/colourations, what goes in comes out uncoloured and true to the source.

Thanks again for your praise Cheers George

Drubin
'...Has anyone here tried the passives from Tortuga Audio?...'

I had an LSA and now have a Tortuga Audio. The only reason I switched was that I found a used Tortuga that had two outputs and of course the remote with volume and balance control is very handy.
Sound wise, I`d be hard pressed to choose one over the other.

So I thought I'd post a bit of feedback now that the LSA has had a couple of weeks of play to settle up.

My regular attenuator is a Townshend Allegri passive which retails for very many times what the LSA costs. Retail price is not a reliable indicator of performance as we know: just setting the scene.

I have to say that the LSA is simply astonishing. It is fluid, extended at the frequency extremes and has a lightning fast attack at the leading edge of notes, then a detailed and realistic decay. Instruments exist in their own space and are distinct from others. There's a quiet confidence to the sound, with a dark background seemingly devoid of interference/noise. No grain, silken and natural.

That's the thing: this really plays music rather than sounding like "good hifi". Music sounds real and involving.

The LSA seems equally happy with Hans Zimmers massive layering and soundstage as it is with Marcus Millers dynamic bass guitar, Army of Mushrooms's bonkers electronica or Jan Garbareks soprano sax. It all works.

In short: Well done George! Overall, the LSA bests the Townshend in my system.

Robert

Nice review. I especially appreciate your decision to wait a while before pronouncing judgement. Too many people jump the gun with conclusions in this hobby.

Has anyone here tried the passives from Tortuga Audio? I haven't, but they use LDR technology and offer multiple inputs, remote control, balanced options and some other features. I'm curious how they compare sonically.

Finally, my definitive review on the Lightspeed Attenuator, by George Stantscheff. Here's what happened...

I was happily playing with a pair of Magnepan 0.6 QRSE speakers, powered by a Portal Panache integrated (and a Velodyne DD12 sub to complement the Maggies). Sweet system, killer bass and I could listen to music for hours without falling asleep or being annoyed.

One day I got the opportunity to trade the Magnepan/Velodyne combo for a pair of fully restored Apogee Duetta Reference speakers (all new ribbons by Graz)... a no-brainer of course. Although the Panache is one powerful integrated, the Duettas really benefit from more power. I did like the amp a lot(!), so I searched and found a pair of Portal Paladin mono amps. Naturally, this meant I needed a pre-amp because I lost the (passive) pre of the Panache.

First I tried the Placette RVC. Nice and compact, features a remote, single input (RCA), single output (RCA). A bit outdated and cheap cabinet, generic Sony remote, but hey... as long as it sounds good. The Placette really delivers in terms of musicality, but I did not like the bass response. Although Placette and the Stereophile review are correct in stating that it's not lean as with other passives, it lacked the impact of active preamps. So I sold the Placette.

Then I tried the Rothwell Indus SE. Average sized box, sheet metal and acrylic front (mine was black, silver controls). Multiple inputs (RCA), dual outputs (RCA), tape monitor, etc. The very unique thing about the Rothwell is the dual volume control. By dividing the steps into a coarse and fine stepped attenuator, it offers a lot of steps combined, while having only two resistors in the signal path at all times, keeping the maximum output impedence a lot lower than most others. No remote though, which was tough after the Placette. However, the Rothwell Indus SE beat the Placette in every area. More tansparent, more separation and the bass had a bit more impact. I liked it so much that I had already developed an add-on module, with Arduino Uno controller, remote, stepper motors and display to stack on top of the Indus SE to be able to remote control it while keeping interferences out of the box. Too bad that personal schedule and the loss of Rothwell's main tech guy threw lead me to sell the unit.

In Nov. 2013 I was picking up where I left, and after a couple of reviews I decided to try a passive pre-amp called Lightspeed by a fellow named George Stantscheff. I was curious about the performance after reading up on the design, and after a brief and very kind conversation about impedances, cable lenghts and what not, I ordered the dual mono model from George directly. Three weeks later it arrived, carefully packed. The box itself is very compact but heavy enough not to be dragged off a shelf by cabling. Single input (RCA), single output (RCA). No remote, but I was simply too curious. A non-switching DC power adapter is included to operate the LEDs which determine the output through the LDRs.

My trusty source for all of these years has been a Pink Triangle Litaural player, so the only difference was the Lightspeed. I hooked it up, set the volume per channel by ear and sat down for a quick listen... which turned into an hour... which turned into hours. What struck me is that I didn't try to analyze the sound at all. Sometimes you read that a 'veil was lifted' or something of that nature, but that's usually just a combination of factors like improved high frequency response, less distortion and the fact that you introduced a new component in your system in the first place, while you anxiously tell your brain to pay extra attention and focus on the details. So I'm not stating that 'a veil was lifted', I was just listening to music and completely struck by the natural level of detail, instrument sounds and dynamics of the music.

As with all new stuff, how exiting it may be at first, you get used to everything in the end. So I decided not to post a review immediately, but wait a couple of months before doing so. In the meantime, I scored a second pair of Portal Paladin amps. After about 6 months of using the Lightspeed, I hooked up the second pair using Cardas F-type RCA splitters. I can tell all purists right away, using splitters is inaudible, period. The real difference was more power, which really opened up the Apogees and controlled them like never before. The bass was even better (due to the second pair of amps) but that also showed mme the Lightspeed wasn't a factor in this, not at all.

However, due to expanding the setup, I felt I should take another 6 months before finally writing this review. So, here we are... hence the opening paragraph: my definitive review on the Lightspeed.

I would go as far as stating that the Lightspeed ended my search for another preamp, even ending my search for other components. It completed my setup and quite contrary to the previous statement that you get used to everything in the end, I am still amazed by the Lightspeed every time I listen to music. It simply isn't there. It shows the strenghts and weaknesses of the source material, the source component, and has no effect whatsoever on the signal going into the 4 power amps. Not doing anything to the signal is the greatest achievement in my book, and this thing is a world champion at it. It fused my components to a coherent system and I've enjoyed it from day one, never ever feeling the urge to 'upgrade'.

Music never ever felt so good, the imaging and soundstaging is superb, tonally everything is what it should be, every instrument is spot on, I can't say anything about pace and such, because all of that is up to the source and power amps in the end. The Lightspeed is perfect in every way, while being as absent as it can be.

Now for the ONLY, very very personal side notes. First of all, for those of you who are absolute control freaks, one word of advise: get the stereo version. I ordered the dual mono version and it can really, seriously mess with your head. It took me a year to just set the volume per channel by ear and be happy with it without wondering if it was 0.5 dB off between channels. If it sounds right, it is right!

Secondly, I would really really like to have a remote control on it, because of the type of volume control it is. Turn it up to 9 o'clock and your older CDs will sound great, throw in a post-1995 CD and your cat will get scare of its life (you may too). Doing every adjustment between CDs will be less stressful when you could remember a good absolute value on a display, easily set with a remote (without loosing the possibility of separate volume control per channel). I personally volunteer to design the volume control add-on box which main task should be NOT to interfere with the beautiful and mindblowing performance of the Lightspeed itself...

Thanks George, for giving us the Lightspeed!

Features: 6/10, Performance: 10/10, Value for money: 10/10

Final setup:

- Apogee Duetta Reference loudspeakers
- Portal Audio Paladin mono power amplifier (2 pairs)
- George Stantscheff Lightspeed Attenuator
- Pink Triangle Litaural CD player
- Grover Huffman ZX 8ft speaker cable (bass)
- Grover Huffman ZX+ 8ft speaker cable (mid/high)
- Grover Huffman ZX+ 1m RCA interconnects (3 pairs)
- Cardas F-type splitters (1 pair)

So, my first post on this here forum after much lurking in the shadows...

I had the chance recently to try the LDR attenuator at home courtesy of
a friend here in the UK and I have to say it's one of the nicest surprises I've had in 30+ years of messing about with high-end hifi. Well done George!

I've ordered one.

Robert

Hi George,

You're welcome!...it's a no brainier to praise your LSA, as it is so good!

Yes, I realized after listening to older cd's that I know quite well, that there is a learning curve in dialing in the perfect balance. Mind you, I have never had a dual balance preamp. I am much better at it now, and it's actually fun to have control over the balance. When it's dialed in correctly, you know it!

Another sonic observation...for ex, I was listening to an older Chesky Cd...(their recordings are really good), Ana Caram's "Blue Bossa", her voice was center, drums behind her, bass to the left, guitar to the right, all in their places, with width, depth, and a naturalness, as if she were in my living room....uncanny really. The speakers are that good, but only as good as what's feeding them upstream.

An older Dorian Organ Recording of Bach's Goldberg Variations, played by Jean Guillou...amazing sense of the church venue, depth, height, 3d sound, I might as well have been sitting in the church. Btw, there is no lack of bass impact with the LSA and these speakers. 40-27,000khz, I have not yet felt the need for a subwoofer. I have one, a Sunfire 10....I am sure that would enhance any recordings such as this organ cd. In fact, how can I hook that up to my system? What's the best way?

Thanks for that great review Soundguy3 (John).
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1276356977&openflup&1635&4#1635

As others that have the Dual Mono Lightspeed Attenuator you will get used to using it, like owning the Audible Illusions Modulus 3a preamp same head space learning curve.

Some customers that have both the stereo and dual mono Lightspeeds have said that prefer the dual mono, as they can get precise stereo image regardless of recordings or system/room imbalances, I think this is more the reason for them preferring the dual mono.

Cheers George

Hi B_limo...ahh, the "phase" plugs. You know, I have the black cones on both drivers...the plugs are black, you barely see them as they blend in with the background of the drivers depending on the time of day of course. At night in low light, you cannot distinguish them from their background.

That aside, the sound is so incredible, and I don't say that lightly, that their looks don't bother me. I think there is a 40 day return policy. I believe once you've heard them, you would not want to return them. :)

Milpai, I was wondering if you were going to be able to pick up on the ringing that George was talking about. Guess its a good thing that you can't!

Soundgyy, good to see another happy Lightspeed owner. I had to sell mine but will have to buy another one when I have the funds available. It's the only pre amp I've had in my system that removes ALL of that slight haze or fog that is present with any other preamp I've tried. Another thanks for your thoughts on the wavetouch speakers; if they didn't look like pinocchio I'd consider them, but I can't get past that "happyto see me" look.

Milpai, I'd be interested in you comparing a Lightspeed to your tvc...

George,
Try as I might, but I could not find any ringing in my TVC, for the past so many days.
One thing I really hoped that Nicholas Chua did better - customer service and response. His TVCs (at least the dual box) are pretty awesome. But I hesitate recommending them to others because of the wait times and unresponsive customer service.

Had the Lightspeed now for about 4 weeks... I opted for the separate volume control for each channel so I could have more control over the balance.

Wow, is the superlative that comes to mind. Having the LSA in the mix is so revealing, it's like removing a layer of film on a window of sound. I have been around live classical music all my life, (pro classical musician). It is amazing how the LSA is allowing clean, clear, full and natural sounds from my system...and this is with some of the equipment that is not new!

Sony XA7ES CD Player

Aragon D2A DAC (prototype)

LSA w/Teralink X2 Upgraded Linear Power Supply DC 8.5V 1A, USB 5V 1A

Newly Rebuilt Pass/Threshold S200 Amp www.vintageamprepair.com (Great sounding SS amp)

Anticable speaker wire (Level 3) www.anticables.com

Ic's are Jena Labs Digital Symphony from the Sony Xa7es digital out to the D2A, and Jena Labs 2 strand ic from the XA7es to the iput of the LSA. LSA to the S200 is a generic ic.

And the speakers...another "WOW"....brand new for me...
Grand Teton SE's. www.wavetouchaudio.com If anyone is looking for the most incredibly revealing, natural, non-fatiguing, beautiful sounding 2 way speakers that are worth far more than their cost, these are it. They really should cost a heck of a lot more than they do! Voices, instruments, floating in space, pinpoint accuracy, holographic, 3D depth and width of the soundstage, even behind me, depending on the venue/recording. I listen to Jazz, classical ensembles, orchestra, Vocals such as Eva Cassidy etc. Pretty much all kinds of music except hard rock. Drums...amazing realistic impact, cymbals etc, all right there... all of these attributes are more clearly defined with the LSA!

The S200 is one great sounding amp in ALL areas. I had it rebuilt/upgraded. I tried several pre-amps, an Acurus L11 and an Aragon 24k, which are both older pre's and not the best...there was no contest..the LSA was clearly superior. In reading about the pre's and LSA, even pre's that cost a lot more, do not beat the LSA.

These speakers are so good, also very sensitive and revealing of ANY change upstream. For example..changing the powercord for the TeraDak power supply to the LSA, you could hear the difference through these speakers. I tried several, one had better depth, but not as clear, another was more upfront, instruments, voices were clearer, but the soundstage was not as deep. Interesting, the best balance is the powercord that came with the TeraDak, and best sounding so far.

In all the years I have had stereo, have never heard this kind of realism and quality of sound coming from my system. The speakers are amazing, allowing one to hear very clearly, how incredible the LSA is.

The 2 volume control is a bit tricky to get just right. At this point, after listening very carefully, just visually getting them in the exact spot, I'm getting good balance.

I leave the LSA on 24/7 as George suggested it will last 50 years instead of 25. :)

What a sound people...this is def a big step towards having live sound in your living room! Great job George...thank you!!

thankyou

I don't know, but if you look at the thread I posted at diyAudio forums on how to make a Lightspeed yourself if you electronically minded.

http://www.diyaudio.com/forums/analog-line-level/80194-lightspeed-attenuator-new-passive-preamp.html

It's ratio is at 1 million hits for 5,000 posts

Cheers George

does anyone have any idea what the view count is for this thread?

Very well put Lacee.

Just two words sum it up "BLACKER BACKGROUND"
This not only improves dynamic range as it lowers the perceived noise floor, but gives you space between notes, as well as transparency to the sound.

Cheers George

I can understand why someone would think that a passive pre amps and a LSA are lacking something compared to a tube active pre-amp.

It's the noise that is seldom ever noticed until it's gone and if you've made the mistake to feel that the pre sounds fuller than an LSA then I think it's the added noise you like.

When I speak of "noise" I mean the stuff that encrusts the music like a spiders web.

You hear the music, it sounds good.
Clean up the noise and the music sounds anemic, threadbare, fatiguing, sterile, pick any term you like.

But it's just the absence of the noise that was filling in the cracks that made the sound "smoother,fatter, sweeter" or pick any term you like for pleasant distortions we all live with and accept.

When you start to rid your system of the "noise"by cleaning up the power from your panel to your gear,and doing the tweaky things that just can't make any difference, you begin to hear your system in a new clear and cleaner light.

You can then more fully appreciate how a clean sounding passive pre (or better yet an LSA) is doing such a great job of not adding any more noise to the system.

I've just done some more tweaks involving Nordost QV2 and several Stillpoint ERS cloths throughout my system.

I can add that the system has never sounded better, and that the LSA is adding nothing to detract from the sound.

Did the sound become more threadbare by eliminating more of the "noise"
No.

What I notice is more detail and space between the instruments and vocals.

The space that was filled with noise isn't .
It just space where there should be space and music where there should be music.
The two are not entwined together in the spider's web.

More than ever I feel that noise is being accepted as part of the sound of some systems that are described as warm, musical and smooth.

And when absent some folks miss it.

They blame the new school of audio design as having lost it's way , lacking soul and of ramping up the treble for the sake of all the old audio farts etc.

The LSA is noise free in my system.

And that's all that I want from any component.
A component that neither adds nor subtracts from the music.

I wish there were more components like the LSA.

Like a metal dome tweeter without a Zobel network on it, they ring very similar and sound "hot".

And the proper word to call it is it's resonance frequency, "ring like a bell" is just slang.

That is why when the TVC is loaded down by a 1kohm load (in my posted Stereophile graph) it damps the resonant frequency out and creates a roll off instead, but then you also have an impedance mismatch.

Cheers George

George,
Can you point out, what to listen for in a music passage, so that some instrument/voice/etc starts to ring like a bell? I will listen to more carefully and see if my TVC does that.

Hwv1 hi.
Thank you very much for your praise and very in depth review. And I'm not surprised it better your TVC preamp, as Shakeydeal also has said, as transformer (TVC/AVC) preamps have a problem as I've outlined to Milpai above.

Yes with any passive preamp or active tube preamp with their high'ish output impedance, when you try to simultaneously drive your main poweramp and a subwoofer amp/s, you create a heavier load for the preamp to see. And it's really only suited for solid state active preamps with their low output impedance to drive.

This problem is the same for any passive or tube preamp, and the way around it is to use a high input impedance buffer in front of the sub amp as you've done, as most sub amp have stupid low input impedance.

Cheers George

Thanks George.

The rising peak into the high frequencies in the first graph I last posted.
If this was to be seen as a square 10khz wave response on a scope, the top of the square wave would be ringing similar to this 1st link, instead of being perfectly square 2nd link.

http://www.digitalprosound.com/2001/03_mar/images/testing/fig8_650.gif

http://imagizer.imageshack.us/a/img14/1007/2u3a.jpg

Cheers George

Grorge,
What do you mean by "rings like a bell starting at 10khz!"? An example would help.

Hi Shakydeal, Sonic Euphoria looks to be out of business.

I can understand why you like LDR passives, this is the problem with TVC/AVC passives, look at the frequency response of it into 100kohm 10kohm 5kohm input impedance of poweramps. It rings like a bell starting at 10khz!

Only into a 1kohm input impedance poweramp does it behave itself, but 1kohm is a severe impedance mismatch, and then it rolls off to early in the HF.

http://www.stereophile.com/content/sonic-euphoria-plc-passive-line-stage-measurements

The Lightspeed Attenuator itself with low capacitance interconnects is flat from 0hz(DC) to mega hertz.

Cheers George

I have tried preamps up to 8K against TVC/AVC preamps and they lost. An LDR was the first thing to unseat my Sonic Euphoria PLC.

Shakey

Stingreen,
TVCs and LDRs are different I believe, compared to the traditional passives. I have tried a $4K preamp with my TVC and nothing was missing.
But like many have said in these forums - it is all system dependent.

I never had luck with passive preamps.. there was always something misssing.

Hi all.
As many of you, I have had the great chance to become the owner of a dual mono Lightspeed Attenuator (LSA).
I should first briefly describe my system so that you can figure out how I use the LSA. A CD drive (Mephisto I, Audiomeca) feeds a highly modified Behringer DEQ2496, of which I mainly use the internal DAC. The DAC output is made of a pair of Lundahl transformers with an output impedance of less than 30 ohms. The signal then goes (went) to a passive preamp (a Stevens and Billington transformer volume control unit (TVCU) using copper TX102 transformers mk1(?)), and then from the TVCU to 2 amps per channel via a Y cable (bi-amp). One cable goes through a VT25 SET amplifier to a wide range loudspeaker. The other cable feeds an "all in one" commercial [class D amp / low pass filter / volume control / phase control] package (Atohm S300) and then a pair of Eminence alpha 15 A per channel below 150 Hz.
In a first trial, I just replaced the TVCU with the LSA, and listen to the CD I was listening with the TVCU when the LSA arrived. Well, the result was not so good. It resembled the sound my former Alps pot provided: listenable but with rather poor definition. I knew the impedance matching between the LSA and the downstream amps plugged in parallel was not good because the S300 has a 20kohms input impedance, which considerably reduces the overall downstream impedance "seen" by the LSA even if the input impedance of the SET amp was (presumably because I do not know it) most probably 50 or 100kohms. So, I simply unplugged the S300 and listen again to the same CD using the wide range loudspeakers only. In this configuration, the impedance seen by the LSA is only that of the SET amps. The difference was like night and day! Perfect definition, perfect sense of space, perfect timbres, etc.
Not only was the LSA extremely transparent feeding the SET amps alone ("true to the source" to use George’s expression, which perfectly accounts for what it is about), but it now even largely outperformed the TVCU! To be more specific about this important point, the CD I was listening to was Handel’s opera Agrippina by Rene Jacobs. With the TVCU, the sound was very accurate but also very harsh. With the LSA, not only all harshness disappeared (I could listen louder without fatigue) but that was not at the price of lower definition. To be sure this was not unique to the first CD I was listening to, I tried another one and got exactly the same result. This meant that the first listening impression was not CD-specific, but was an actual difference between the TVCU and the LSA.
Surprisingly, although I was listening through wide range loudspeakers only (remember the bass loudspeaker amps were not used anymore to solve impedance matching issue) I could hear very good bass! I conclude that the LSA also improved the bass, a result that could not be achieved using the TVCU, which sounds lean without the support of 15' loudspeakers.
George suggested inserting a buffer between the LSA and the bass amp to solve the impedance mismatch issue. He was kind enough to even propose a link to a very cheap buffer. Unfortunately, the access to the buffer was denied by ebay for some reason. After a very limited search, I found a ready for use buffer sold by Indeed (Hong-Kong), which I bought. Indeed buffer has an interesting 1Mohm input impedance and a less interesting “more than” (?) 5Kohm output impedance. Since the latter was lower than what I read was that of the LSA (7Kohms, is that correct George?), I thought Indeed buffer was worth a try. After a few weeks, I received the buffer and plugged it between the LSA and the bass amp. The result was perfect! Since then, I have not changed anything to the set-up and enjoy rediscovering my CD collection.
As a provisional conclusion, I would say that I am more than satisfied with the LSA, and that George is a great researcher and a great creator whom I thank for making this jewel available to us simple human beings...
Good listening to all,
Christophe.
PS. I would like to specify that the goal of the above review is certainly not to denigrate the Stevens and Billington TVCU. When it replaced my Alps pot a few years ago, it really improved the sound, and I have enjoyed listening music thanks to it.

Wrong type of just. It should be judge.