Lightspeed Attenuator - Best Preamp Ever?

update
wow, what a different it make,after I change wallwart to terdak, the lightspeed became more slam & dynamic. frankly this got to be the best hifi investment I ever make.

Hi Georgelofi, come on over to the cable thread,Taralabs 0.8 versus the one, there you will find a member friend of mine that is interested in your product, His name is waxwaves, read the last few post, if you could agree with my findings and back me up concerning all that I said about active pre-amps versus source direct to amps, and addresse waxwaves about your product, I would be grateful, thankyou George.

So So no big decal HELLO!!!!!

What do you mean by your post Ebm?

Hi, Audiolabyrinth, tell him to come over here and read this.
I had a quick read of that thread, and there are those that like to be on the preamp merry-go-round, spending lots of money and are addicted to it.

They say that their preamps aren't coloured. But keep changing them for "different sounding ones" (odd I thought they were uncoloured).

I have yet to hear them use the statements like "straight wire with gain" or "true to the sound of the source" as these statements are describing a preamp the is truly transparent, dynamic, uncoloured and invisable to the sound of the source.

Cheers George

Georgelofi, It would be an honor for you to come to the thread I requested, there is a need there for your vast exsperience, comment on all subjects, as you can see, this thread is unlike most others, we talk about all audio, not just the subject of the thread, please.

Have been reading with interest the comments about the TeraDak and keces DC-116 power supplies and am encouraged that users are happy with the TeraDak given its considerably lower cost.

Is AB Systems (source of the TeraDak) still in business? I have written emails to the Contact@ listed but have not received any responses over the past several weeks. As expected, I am reluctant to order anything blindly.

I understand that Input Voltage must be specified.
I also see that Output Voltage is "adjust" between 0.25V and 9V. Is output voltage adjusted by user...or preset by the vendor to user requirement?

Also would like to know what the DC connector barrel dimensions are...5.5mm/2.1mm or other?

Anybody have any experience with their other products, e.g., power cords?

Thanks!

AB Systems was off for the Chinese New Year which ended a few weeks ago I beleive. Just before that, on January 10, I ordered the TeraDak U9VA for use with my LSA. It arrived within a few days from China, kind of surprising how fast. Very happy.

There was no need to specify the voltage for the U9VA, it came PnP for the LSA; all I needed was to use my own PC.
This model doesn't have an adjustable output voltage. Nevertheless, it's not necessary when using with the LSA. I am supremely happy with my purchase and highly recommend AB Systems.

About three days ago I sent AB Systems an e-mail about and have not heard back. I hope all is well.

~Tom in Sacramento

I also see that Output Voltage is "adjust" between 0.25V and 9V. Is output voltage adjusted by user...or preset by the vendor to user requirement?

There's nothing to adjust on mine--at least not on the exterior.

I bought mine from their bay store, but I see that they have nothing presently for sale...hmmmm.

I came across this thread in my mission quest to find linear, regulated power supplies. I have a non-LSA application and need 5V @ 3A output with a 120V input. However the specs listed on the site seemed to be just what I need since it indicated
"DC output: 0.25V-9V adjust (Default DC 9V 1A)"
though I am not sure what the maximum amperage is if not the 1A indicated.

Need to wait and see if my "proof of life" inquiry gets a response. ;-)

IF anyone knows of another linear, regulated alternative to the TeraDak other than the pricey and overkill KECES D-116, I would love hear about them.

I have a Teddy Pardo 12V/2A PS here. Can I use that safely with my LSA?

Drubin, I wouldn't use the Pardo;the 12V/2A will fry it. The LSA takes 1A max I beleive. I'm not an expert, maybe others with more knowledge will chime in here...

03-03-14: 4hannons
Drubin, I wouldn't use the Pardo;the 12V/2A will fry it. The LSA takes 1A max I beleive. I'm not an expert, maybe others with more knowledge will chime in here...

Sorry but just to correct this, it will work fine, so long as the plug that goes into the Lightspeed Attenuator is 2.1mm and centre positive. Voltage can be between 9vdc-18vdc.
True 2amps is way way over kill, but the amperage does'nt matter so long as it's above 100mA.

Cheers George

Has anyone heard any of the LDR products from Tortuga? They have addressed the need for multiple inputs and remote volume control at prices that are not unreasonably higher than George's, so I'm curious how the stuff sounds in comparison.

Audiolabyrinth:
Thanks for the invite, but cables and how they sound are such a subjective thing, and very system dependant.

All I say that for all passives and high output impedance tube preamps, one should make sure that the capacitance of the cable is low, as not to form a HF (high frequency) filter if the capacitance of the cable is too high.

Luckily good quality cables are nearly always low capacitance, and just to be certain you should ask the manufacturer.

A good worst measurement case is 100pf (pico-farad) per foot or lower good ones are much lower, for a 1mt interconnect this worst case capacitance would be 300pf, this equates to with a passive and many tube preamps to have a HF (high frequency roll off at around -3db at 76khz.

But if you pick an quality interconnect that is 50pf per foot, then the HF roll off is -3db at 152khz.

Cheers George

@ Georgelofi, Wow!, My interconnect, The Taralabs Zero Gold's capacitance is 4 pf per-foot!, then the new Taralabs Evolution Grand master interconnect is 2pf capacitance per-foot, I'm good with the capacitance specs then!, thankyou for your reply Georgelofi.

Yes this what good interconnects should be, as little as possible capacitance.

Otherwise if over 300pf total for a 1mt length, they will start to create 1st order (gradual) HF (high frequency) roll-off's into the audio band when combined with nearly all passive preamps and many of the tube preamps as well.

Giving the impression of sometimes sweeter highs less sibilance (if the system has some).
And because the top end has been curtailed a little less detail, it can also give the impression of more bottom end or richer lower midrange.

Cheers George

I didn't measure capacitance or anything but after trying quite a few interconnects, I found the Purist Audio Museaus to work fantastically with my Lightspeed. Cleaner, clearer, more true.....

Dhcod hi,
I had a bit of a search and yes your Purest Audio cables are very good low capacitance ones.

They are fine to use with many tube and most passive preamps, and will not cause early (into the audio band) high frequency roll off.
I would keep these to a max length of 1.5mts from pre to poweramp.

I looked at most of the ones they give specs on, and they give the 1mt length pF (pico-farad) capacitance and all that I saw are under the 100pf per ft measurement I gave earlier.

This is good to know that some cable manufacturers are responsible and doing this specification for their customers, who know how to use it, for their systems compatibility with them.

http://www.puristaudiodesign.com/products/interconnects.php

Cheers George

Just wanted to thank George for a great job well done with the lightspeed attenuator.. The music in my system has really opened up and I'm hearing instruments more clearly in background with better detail then I ever had before.. The instruments sound so realistic as if I was right there and the voice's are so clean and airy..

I'm running the lightspeed with pass labs x250.5, Oppo bpd-105 and Eggleston fountain 2 speakers and am very happy with the results after over 20 years of listening my search is at last over..

Thanks George for a great product with good customer service.
Dave

Great Passive Preamp. Received light speed from George two weeks ago. In my system the light speed has great dynamics and clarity. System is primaluna prologue five tube amp and Tyler acoustics PD 15 speakers. Thanks George for a wonderful product.

Hi everyone, I have a question about the TeraDaK U9VA power supply, which I recently bought. The ac input is too large for the 2.1mm connector used by the Lightspeed. I asked the TeraDak manufacturers how to convert the plugs but the language barrier is preventing me from getting an answer.

What adapter have the folks using the TeraDak with the Lightspeed been using? If you have an online link, that would be very helpful. Thanks.

Jult52: I just use whatever came stock with the unit; no adapters needed. I do note that the cord juts out a bit when plugged into the LSA, but it is powering the unit as it should.

Perhaps the Teradak people changed their stock cord?

Never had any problems attaching the two with what came from TeraDak.
Perhaps you should contact them for the answer,and enlighten others who may want to purchase the "newer"units if in fact they have made a switch.
Perhaps they are offering an alternative to the previous cord.

I pushed the TeraDak ac input plug into the LSA and, though it isn't the right size, it powers the unit. Problem solved. Thanks for the advice, Banquo & Lacee.

I'll try and do some careful listening and come back with a report on how the TeraDak compares with a SMPS wallwart.

The ac input plug is available from www. ab-system.hk

~Tom in Sacramento

Is this cable listed under power cables on the ab- system.hk website and is 11.00 USD.

I think he means one of these esoteric ones.

http://www.ab-system.hk/index.php?route=product/product&path=78&product_id=172

http://www.ab-system.hk/index.php?route=product/product&path=78&product_id=173

Cheers George

George will these cables fit the 2.1mm dc connector on the lsa.

Has any one used his LSA with active monitors?
mine do have an input impedance of 10KOhms, which is not the recommended 47Kohms.
Output impedance of the source is extremly low though.
any thoughts?

04-28-14: Digital3
George will these cables fit the 2.1mm dc connector on the lsa.

Yes, the Lightspeed Attenuator has a dc socket that has a 2.1mm centre pin, 5.5mm external, plug. The centre has to be positive which I believe the TeraDac is.

Cheers George

04-28-14: Luxsound
Has any one used his LSA with active monitors?
mine do have an input impedance of 10KOhms, which is not the recommended 47Kohms.
Output impedance of the source is extremly low though.
any thoughts?

It all comes down to what the source can drive, because it will need to drive the combined load of the Lightspeed and the active speakers If it (the source) has a very low output impedance say below 50ohms there should be no problems.
But say it (the source) has a tube output stage then some of these can be very high in output impedance ( some up to 5Kohms), they could have trouble in this particular case.

Cheers George

No problems with my Acoustats,the ones with the servo charge tube amps.

I have been using my dual mono version for a few months now. It has always been dead quiet and did great things right out of the box. I have recently added the rechargeable battery and it has pushed things to an even higher level.

I know that some people said that it wouldn't make a difference using a battery supply but for me it did. It sounds even more natural and more information comes through.

That's cool, Detredwings. Can you provide a link to your battery pack.

I bought a battery for my LSA years ago and the differences were subtle at best. But the battery was suspect and died within a month. I'd like to try batteries again even though I'm very happy with the Teradak.

These are the Ebay 12vdc rechargeable Li-Ion batteries (and similar) that I have been recommending, they have (usually) 2.1mm plugs and centre positive. which is right for the Lightspeed Attenuator, just check to make sure.

All users say they prefer the battery to the linear wall wart but can't pinpoint why. Even Sam Tellig (of Stereophile) says "it's that's close that sometimes he forgets which he has on", but they're cheap enough and give a couple of weeks use before a recharge is needed.

http://www.ebay.com/itm/12V-DC-Rechargeable-Li-ion-Battery-CCTV-Cam-6800mAh-F47-/221117937029?pt=US_Surveillance_Accessories&hash=item337ba7f585

Cheers George

I compared the LSA with a switch-mode ps and the linear TeraDak 9v supply discussed earlier in this thread. I am going to report a null result: I could not reliably differentiate between the sound of the two. The TeraDak carried no benefits in my system.

Hi George,

I've been enjoying your Lightspeed Attenuator for three days now, and it prompts the following remarks.

As a lifetime analog fan, I only lately invested in a truly great CD player, an oppo 95 with Ric Schultz's all-out mods, only to discover that the digital volume control noticeably degrades information at lower -and what I would consider reasonable- levels. Additionally, the increments are less than subtle, and the lowest audible setting is still too loud for my taste. A friend told me that digital volume controls deserve to be banned. I concur.

In my experience a system's ability to resolve lower levels is essential. Not being the diy type, I started looking at stepped attenuators that plug directly into the amp output, and therefore would require one less interconnect. The only two I found, Ric Schultz and Scott Endler's, were unfortunately no longer made, and TVC's have their own issues. After discovering your LightsSpeed Attenuator on diyaudio.com, I ordered one a couple of weeks ago, which arrived safely ten days later.

I think the best way for me to describe the LightSpeed is that with the CD volume control set to maximum, I can now listen to my interconnects, not to the unit itself, because in every respect -style, size, sound, and setup- , it simply stands out of the way. I power it with an older car battery. It's always difficult to describe a product which has no characteristics of its own, whose presence is in its seeming absence, which adds or subtracts nothing, but the end result is that I now listen far more often to far more music which is far more enjoyable. For $450 I'm finally experiencing the full potential of what I consider to be an exceptional CD player, which now comes very, very close to my $15,000 analog source. I have yet to try the LightSpeed on the REC OUT of my phono preamp, probably because I am enjoying it so much on digital.

The only limitations I can think of, have nothing to do with the sound: leaving the volume control half-way to extend the life of the optoisolators took some getting used to, and indeed the lowest setting lets will let some minimal signal through, which compared to my previous setup, however, is well within my tolerance, and greatly superior to my earlier direct CD to amp connection. The overall experience is far beyond my expectation. This is a product that I will not be parting with, period.

You asked about the volume setting for normal loud listening with the Oppo at full. It's at ten of twelve maximum. If I want to increase that setting, I can then use the remote on the oppo while retaining excellent definition.

05-19-14: Erwann
The only limitations I can think of, have nothing to do with the sound: leaving the volume control half-way to extend the life of the optoisolators took some getting used to, and indeed the lowest setting lets will let some minimal signal through, which compared to my previous setup, however, is well within my tolerance, and greatly superior to my earlier direct CD to amp connection. The overall experience is far beyond my expectation. This is a product that I will not be parting with, period.
Erwann (Answers | This Thread)

Glad you like it so much Erwann, as for leaving it at 12o'clock when not listening, this is not set in stone, as the leds should last 10-20 years at full power, which I never run them at, and by leaving it at half volume should double or tripple this life.
PS don't forget to let us know how your $15K!!!! analogue source sounds through it when you get the chance, as analogue lovers have told me it's the best they have ever had their records sound.

Cheers George

Hi George,

I just had a quick glance at the Audiogon thread to figure out whether I can find a better power supply than my decommissioned Prius auxiliary battery, and I fail to understand how a Teradak, with or without a fancy cord, could offer an improvement other than convenience. I guess the answer is that you haven't felt an overwhelming urge to try it yourself. Not being an exhibitionist, I personally think that my best audio component is my brain with ear input, which in addition to being portable and self-powered, doubles as the biggest sex organ, but I'm still burning it in at sixty-six, and it keeps improving.

Please do try the LSA with your phono stage.
I run my Steelhead volume full out and the LSA under 12 with very good results.
In my system, the Terra dak with upgraded power cords in conjunction with dedicated lines is an improvement over the stock LSA and walwart.
No doubt your power supply is also much better than the stock walwart.

I use the Annaconda power cord only because it was a spare,but I would assume any upgraded power cord would work quite well with the LSA/TeraDAk combo.

However if you haven't been able to hear the differences power cords can make with other components, then by all means use whatever you have at hand.

It's not about one-upmanship,just being practical without selling it at a loss.

Besides what would I spend the extra dough on?

05-09-14: Jult52
I compared the LSA with a switch-mode ps and the linear TeraDak 9v supply discussed earlier in this thread. I am going to report a null result: I could not reliably differentiate between the sound of the two. The TeraDak carried no benefits in my system.

Hi Julian, I noticed on another forum you did a comparison with the Lightspeed up against another clone, and mentioned the Lightspeed Attenuator had the better bass performance.
I believe there could one of 3 factors for this difference.

1: The main one I'm leaning towards may be that the Lightspeed has no contacts in the signal path, where I believe the clone has, as it has input switching. And the whole point of the Lightspeed when I first built the original in the 70's was to eliminate any switches or volume pot wiper contacts from the signal path.

2: I also use quad matched LED/LDR's in the Lightspeed, this keeps the i/o impedances more stable, and also gives a better logarithmic feel to the volume control, I believe the clone only uses 2 x matched pairs.

3: I use the more expensive NSL32SR2S, where the clone from what my spies told me does not.

Cheers George

05-19-14: Erwann
Hi George,

I just had a quick glance at the Audiogon thread to figure out whether I can find a better power supply than my decommissioned Prius auxiliary battery, and I fail to understand how a Teradak, with or without a fancy cord, could offer an improvement other than convenience. I guess the answer is that you haven't felt an overwhelming urge to try it yourself. Not being an exhibitionist, I personally think that my best audio component is my brain with ear input, which in addition to being portable and self-powered, doubles as the biggest sex organ, but I'm still burning it in at sixty-six, and it keeps improving.

I strongly believe that battery is the "technically" the best form of dc supply for the Lightspeed Attenuator.
But sometimes I forget which is on mine, the battery or the linear wall wart, they're that close to each other.
Sam Tellig of Stereophile uses both battery or wall wart on his Lightspeed, and so does his guitar teaching son on his Lightspeed. And both can hear a slight difference but can't say what that difference is.
As for the Teradac power supply, if you technically want a very good mains powered supply for the Lightspeed that to me is total overkill, this is the one to get. And it's only $44.
Some here that have used it, swear it's the ultimate mains powered supply. I have never used one so I cannot comment on it, but on paper it's miles ahead of a linear wall wart, but to me technically battery is even better again.

Cheers George

My analog front end is a vintage Verdier driving a London Decca Reference cartridge on a Cartridge Man Air Bearing tonearm. With its 5 mv output the Decca is not exactly shy, so signal strength is not a concern with the LightSpeed .

I use the phono stage of a modded EL34 type Scott amp, which in terms of what I would consider absolute musical value, is without peer. The ability to further tap that value upstream via the REC OUT into the LightSpeed Attenuator is the equivalent of adding Bybee Golden Goddess 'Super Effect' Speaker Bullets, which to me, was a revelation, and is of the same order of magnitude as being able to bypass that dismal digital attenuator on my Oppo, whose potential has finally materialized.

For me, pace and tone are paramount, and trump imaging any time. Music is not about hollow graphic photography, but about living the performance. The Lightspeed clarifies intention and complex interdependence between notes the way a juggler keeps his balls, up in the air where they belong (sorry about that).

Insofar as the only weakness of the Lightspeed is the additional interconnects required, time permitting I hope to experiment with the diy version of the Tempo Electric Aurum Ag Hybrid interconnects, which should do justice to this exceptional little gem.

Ewrann (Gerald), thank you very much for the kind words on how the Lightspeed performed with vinyl, and for rekindleing my memories for the Decca London cartridges, which on a great TT/arm such as you have, were one of the best sounds I could get from vinyl, the slam and dynamics still live with me today.

For those young bloods reading this, here are some similar pics of what Gerald's setup is for vinyl repaly.

http://www.tnt-audio.com/sorgenti/conductor_e.html

http://www.blackpearls-shop.de/DECCA-AEC-LONDON-REFERENCE-TONABNEHMER

https://www.flickr.com/photos/hannes_frick/7645363880/

Cheers George

Hi George,

I don't use the Isolator cartridge/headshell de-coupler pictured at
http://www.blackpearls-shop.de/DECCA-AEC-LONDON-REFERENCE-TONABNEHMER

Instead, I couple the Decca to the arm and the arm to the 'table with Mapleshade's Nanomount System,
(http://shop.mapleshadestore.com/prodinfo.asp?number=NANOMOUNT).

Mapleshade's no-nonsense vibration control products shame anything else for a fraction of the price, which is exactly what you've managed to do. Its founder, Pierre Sprey, fathered the legendary A-10 Warthog, recently rescued from extinction by Congress. It's the only USAF aircraft designed solely for close air support capable of extended loitering over the battlefield, to devastating effect, again for a fraction of the price of an F-35. Have a look at this: http://www.motherjones.com/mojo/2012/01/a-10-f-35-air-force-budget.

Your LightSpeed is the stealth version A-10 of the audio battlefield. Simply devastating!

Here is another reasonably priced linear powersupply, you Lightspeed owners may wish to play with, with digital readout!!
It has the correct size output plug, at 2.1mm X5.5mm with center positive.

All you have to do is specify 220v or 110v mains and say you want the output set for either 9vdc or 12vdc. Both voltages work, as I have a second regulated supply inside the Lightspeed which re-regulates again.

http://www.ebay.com/itm/Hifi-linear-power-DC-1-USB-amp-DAC-external-power-supply-with-digital-display-SN-/221458260575?pt=US_Home_Audio_Amplifiers_Preamps&hash=item338ff0e25f

Cheers George

This only applies to UK and European Union members.

There seems to be complete ignorance about these Light Dependent Resistor products. A word of warning really needs to be published about LDR based pre-amps. LDRs contain Cadmium gas which is lethal (kidney or liver failure) if eaten or breathed and is a long term serious health (Cancer) risk if just touched on a regular basis. Because of this it is illegal to import or sell these items within the EU as they are not RoHS or WEEE approved, so cannot be given a CE mark. This is true for both kits and built products.

So is the Beryllium(Be) used in Focals/JM Labs and other speaker manufacturers that use Focals top tweeters.
So is Yamaha NS1000, NS1000X and NS2000, tweeters and midrange units.

So is NOS and OS tubes that have Nickle(Ni) inside them.

And so is the lead(Pb) based solder hiend manufactures still perfer to use.

I can go on and on, at least the Silonex LED/LDR package that the Lightspeed Attenuator uses, are hermetically sealed within a tough hard acid resistant plastic case, I don't think anyone is about to open up a Lightspeed Attenuator put one in their mouth and crunch down on it like a boiled lolly. It's not "Cadmium Gas" it's Cadmium Suplhide (CDs) solid.

http://en.wikipedia.org/wiki/Photoresistor

http://en.wikipedia.org/wiki/Cadmium_sulfide

Cheers George

This is vintage EU mind control: identify genuine existential problems, say the girth of bananas, to justify a metastatic bureaucracy, whose days, judging by the latest EU Parliament elections, are numbered.