Are there passive attenuators that don't zero volume and only offer one input ?


I am not sure how many people would like those features, but its worth asking in case someone would try to sell such a thing.

Which is to say it is essential I should think  to be able to zero volume, and have more than one input, do you agree ? 
dbxrecord
Are there passive attenuators that don't zero volume and only offer one input ?
You've just described the Lightspeed Attenuator to a tee.

Cheers George
This sounds like something I could use but it would need to have XLR ins/outs. My preamp has two "pre out" pairs: one RCA, one XLR. The XLR are 2-volts hotter than RCA so would be louder if trying to bi-amp. 
Sure, Khozmo and Hattor. I just recently received a Khozmo dual mono passive attenuator with separate left/right channel volume adjustment, one input, two outputs (one for subs), all balanced XLR ins-outs, display, and remote control of all functions. I use it for remote volume adjustment in conjunction with a unity gain buffer. Discrete resistors with Takman REY metal film shunt resistors and a Vishay "nude" Z-foil series resistor.
Placette passive. 
Are there passive attenuators that don’t zero volume and only offer one input ?

The op wants a passive pre with one input, that doesn’t go to zero, all the ones mentioned above do zero the volume.
As far as I know only the Lightspeed at minimum volume still has a small amount of output, as Light Dependent Resistors (ldr) can’t attain absolute zero impedance.

Cheers George
What is the benefit of a passive attenuator that "don't zero volume"?
Is there some sonic or operational benefit?  What am I missing?
Just curious.
I don’t know either, maybe a safety factor against accidently leaving things running, works for me sometimes when I’ve had a few too many🤷‍♂️🤷‍♂️

Cheers George
I think you can have one made from here:
https://www.passivepreamp.com/

All the best,
Nonoise
I have heard George’s Lightspeed Attenuator, and I have to say, it is the most " invisible ", that I have heard ( or actually, not heard ). I require multiple inputs, and enjoy remote volume, which are reasons I do not use one. I personally never liked TVC units myself.
I personally never liked TVC units myself.

I agree, TVC passives are usually colored, softened in dynamics, also in the frequency extremes. I would say they might appeal to those that like laid back SET tube amps.

BTW: before anyone sez anything "snidely"
I’m NOT trying to sell the OP a Lightspeed Attenuator (I’m sure he can find a used one somewhere) As all my production has stopped, till this Covid mess sorts itself out, so OS shipping is back to being reliable, as the last one took 3mts to get to the customer.

Cheers George
That coloring/softening is why I didn’t care for the sound of the Acoustic Imagery JaySho (which is basically a Bent).  That sound can be a subtle effect but it is there.  I have 3 resistor passives here now, Goldpoint, Endler, and the Khozmo that I like best.  Takman REY shunts and Vishay "nude" Z-foil series resistors in the Khozmo.  The Endler sounds a little coarse or unrefined, the Goldpoint with SMD resistors is clean but maybe a touch thin, and the Khozmo doesn’t have much of its own sound at all.  It is definitely more neutral than the Shallco volume control using AN Tantalum resistors that I took out of the signal path of my preamp - which is now a buffer.  The Khozmo was very reasonably priced considering the features and the sound quality.
The op wants a passive pre with one input, that doesn’t go to zero, all the ones mentioned above do zero the volume.
As far as I know only the Lightspeed at minimum volume still has a small amount of output, as Light Dependent Resistors (ldr) can’t attain absolute zero impedance.


Quite the opposite actually. Referring to my first post, it can be seen not being able to zero volume, or have more than one input, is not desirableat all.

Both are serious compromises, that designs must overcome.
If you want to use LDR's , as I observe in other designs, they find it easy to both achieve silence at zero volume, and to also have as many inputs, as are required.  
If you want to use LDR's , as I observe in other designs, they find it easy to both achieve silence at zero volume, and to also have as many inputs, as are required.  
True but it's not as pure a signal path. I have owned my LDR passive (Lightspeed) for over 10 years. I have also built/owned other resistor and transformer based passives. The simplicity of the Lightspeed and the ability for it to stay out of the way more so than the other passives is why it is the one that stays in my system.
I'm in agreement with mitch2 - the Khozmo represents exceptional dynamic transparency, and an attractive price.  I use a stereo version, with three inputs and two outputs, Vishay Nude Z-Foils and Takman REX shunts (carbon vs metal film of the REY).  I have two Khozmos, the older one using a stepped attenuator (with Takman REY and the same Vishays), and the newer unit which utilizes relays for volume control.  Both are superb, but I think the relay based unit is the more transparent of the two.  My previous "volume knob" was a set of Intact Audio/Dave Slagle autoformers, via a Shallco stepped selector and a Bent remote control kit.  An excellent unit, which the Khozmos finally displaced.
Here is a balanced attenuator that I just made for someone.....he loves it.

http://tweakaudio.com/EVS-2/custom_modsultimate_attenuators.html
True but it's not as pure a signal path. I have owned my LDR passive (Lightspeed) for over 10 years. I have also built/owned other resistor and transformer based passives. The simplicity of the Lightspeed and the ability for it to stay out of the way more so than the other passives is why
it is the one that stays in my system.

But what I observe is other LDR attenuators, based on what I have learned may be the NSL32SR3 type of LDR, apparently these can offer better audio characteristics, namely lower distortion, the manufacturer Luna Inc stating "best distortion characteristics"  and also as I understand, providing wider resistance range.

Apparently they are also able to easily zero volume with a clever technique, and offer more than one stereo input, as I understand as many inputs that are needed, can be catered for. 

It would  seem then easy enough to solve, not to have  problems like not being able to zero volume, if designs, and designers, have motivation to do so.  The one you mention appearing after so many years,  to lack any motivation whatsoever, to overcome the two said issues.


But what I observe is other LDR attenuators, based on what I have learned may be the NSL32SR3 type of LDR, apparently these can offer better audio characteristics, namely lower distortion, the manufacturer Luna Inc stating "best distortion characteristics" and also as I understand, providing wider resistance range.
This is BS, do your own homework.
The very best is the NSL32SR2S and is the most expensive, second is the NSL32SR2.
The R3 is the cheap one and doesn’t go low enough in volume unless over powered/stressed and won’t last if done so.Cheers George
This is BS, do your own homework.
The very best is the NSL32SR2S and is the most expensive, second is the NSL32SR2.
The R3 is the cheap one and doesn’t go low enough in volume unless over powered/stressed and won’t last if done so.


First off observe the incivility of language being used in the first paragraph, and the attitude of demeaning.  He would do well to learn to tackle the subject, & not the writer.

Lets look at the subject. The manufacturer Luna inc states  for the NSL32SR2S " low distortion"   , and for the NSL32SR3 " best distortion characteristics "  best,  in my dictionary The Concise Oxford has the following meaning: " of the most excellent, or outstanding, or desirable kind "

The second part of his reply,  its easy to assess that pricing of goods of any business relates to the number of units being sold. Indeed the SR2S is more expensive as a direct result of fewer being stocked and one would have to then think units sold, a weak point in his reply to raise.  Trying as we see, to attribute higher cost, as being better. As example today DigiKey stocking 13611 of the SR3, and just 897 of the SR2S.

but lets go on, he states as we see 
doesn’t go low enough in volume unless over powered/stressed and won’t last if done so.

He refers here to 20 ohms of difference that the SR2S has when powered with 20ma of current, vs  the SR3,  his attribution being needed to go low enough in volume. 

Herein the problem, finally exposed, deep breath ... one does not need to raise current, to achieve low or zero volume with LDR's.  In fact other designs achieve current draw of no more than 3ma total at all volume levels which includes the entire circuit, with the benefit of no stress at all, to the LDR's

Another issue being lowering shunt resistance too low, appeasing to achieve low volume, does nothing,  other than squashes available dynamics in music. It is far better to have a higher resistance to begin the shunt resistance range, with the NSL32SR3 its possible though to have 100 ohms at zero volume, and 56k by mid volume with the shunt pair , and to have  25 mega ohms at zero volume with the series pair and 18k at mid volume.   That though does take quite a bit of design effort.... but it can be done.
Other designers providing LDR attenuators worked this out many years ago how to zero volume, and to provide more than one stereo input,  without using higher current , they even went to the trouble of publishing how to do it, for everyone's benefit.  



I owned the Placette Passive and one of my friends still owns one. They are fantastic. Mine was a 4 input, one output version. My friend's unit is a 3 input, 2 output unit.

I would still have it, except I decided to go to an integrated amp to free up some audio rack real estate.


The S3 ’s are widely all over the place, almost impossible to get few "quad matched sets" to do a Lightspeed properly with close to zero volume low volume, unless they are forced matched with servo feedback arrangement and by over driving some which "raises the distortion substantially" to meet the others which will kill them over a very short period.

NZ shysters
Chris Daley? JAVA ldr passive preamplifier $3.5K!!!!!!


The S3 's are widely all over the place, almost impossible to get few "quad matched sets" to do a Lightspeed properly with close to zero volume low volume, unless they are forced matched with servo feedback arrangement and by over driving some which "raises the distortion substantially" to meet the others which will kill them over a very short period.



Actually the SR3 are better in my experience than the SR2S for matching. There is no need either, to use servo feedback arrangements.
Keeping current 3ma for the whole circuit is the key. Sweeping between lowest volume and highest should achieve variance of just 2.78ma to 3ma , for the entire circuit, encompassing the load of 4x NSL32SR3 

There is no need to go any higher at all, which keeps distortion extremely low, and achieves much better stability with cell resistance. 

R(on) of 20ma per device, or anywhere near that figure, is thus neatly avoided .   





Whatever, why did you start this thread, if you know all the answers 
The S3 ’s are widely all over the place, almost impossible to get few "quad matched sets" to do a Lightspeed properly with close to zero volume low volume, unless they are forced matched with servo feedback arrangement and by over driving some which "raises the distortion substantially" to meet the others which will kill them over a very short period.

NZ shysters
Chris Daley? JAVA ldr passive preamplifier $3.5K!!!!!!

I have no association with either name, please stick to the subject rather than libel. 
Like I said.

"Why did you start this thread, if you know all the answers"

And add yourself to the list,
https://robmid42.wixsite.com/diyaudiokits/stereo-coffee-preamplifier

And the dreaded "pass transistor" https://ibb.co/HKwPhsh 

https://www.head-fi.org/members/dbxrecord.192735/

over and out!
I said.

"Why did you start this thread, if you know all the answers"

Over and out!

If you read the first post it asks a question.  Am i right in assuming you are you somehow totally OK,  with all passive preamps not being able to zero volume and offering one input ?

The discussion points, that its not too hard to do, even with LDR types.

I really hope not, rather hopefully your response would be on reflection,  that would be much better for all passive preamps to have silence at zero volume, and offer more than one stereo input. 

The question is there for all to respond to, perhaps we can see from others contributing, that not being able to zero volume and only provide one input is really undesirable, in fact dreadful,  now knowing its easy to correct.

It remains for those marketing passive preamps, that it is quite easy to turn around, to be a success story instead,  and that is what the thread is all about.... improving what is out there.
NZ shysters
Chris Daley? JAVA ldr passive preamplifier $3.5K!!!!!!

I have no association with either name, please stick to the subject rather than libel.

You’ve been caught out sunshine, you want more posted up from diyaudio also

https://robmid42.wixsite.com/diyaudiokits/stereo-coffee-preamplifier

And this is the "Chris Daly" famous opamp "pass transistor" con job, which you use as an avatar!!!! here https://ibb.co/HKwPhsh
https://www.head-fi.org/members/dbxrecord.192735/

These are my last words, I'll leave the rest to admin come Monday if you continue.

You’ve been caught out sunshine, you want more posted up from diyaudio also

https://robmid42.wixsite.com/diyaudiokits/stereo-coffee-preamplifier

And this is the "Chris Daly" famous opamp "pass transistor" con job, which you use as an avatar!!!! here https://ibb.co/HKwPhsh
https://www.head-fi.org/members/dbxrecord.192735/

These are my last words, I'll leave the rest to admin come Monday if you continue.
Maybe deal with the topic instead , refer to post 1 if you need to. 




@dbxrecords ....why not just disclose or post under your industry affiliation?
Not being an engineer here, any sound comparisons, opinions regrading the Axiom Passive Preamp? Thanks 
@dbxrecords ....why not just disclose or post under your industry affiliation?
If this thread is anything to go by, it is obvious a code of ethos is desperately needed.  Until then,  sorry but few would submit themselves to such abuse.  Let alone give up personal information,  to be potentially subjected,  to more of the same.

Here as example is a forum with a code of ethos, that is good to reflect on:  
https://theartofsound.net/forum/showthread.php?17-The-basics-of-Ethos

  


@bigwave1 - The base Axiom uses a shunt to ground design that they indicate keeps the signal path away from the Alps potentiometer. I believe Joule did something similar on their preamps. The upper end Walker Mod models use Khozmo’s discrete resistor attenuators. I looked at both Axiom and Khozmo earlier in the year and went with the Khozmo. I liked the small form function of the Axiom but was ultimately able to have more/better features with the Khozmo, including L/R channel control, larger display (for each channel), and my choice of resistors. Khozmo also has an upscale brand, Hattor, with even more feature possibilities such as an active stage and more substantial chassis, but I am not convinced those would sound any better than the Khozmo line for a purely passive unit. If you want the choice of switching from passive to active using a high end op-amp or even a tubed stage then look at the Hattor line.
Perfect, thank you mitch2
Which is to say it is essential I should think to be able to zero volume, and have more than one input, do you agree ?
No.
Every contact, additional component and wire/trace affects the sound. Anything below -20dB is pointless with properly configured gain structure.

Is it HiFi or sonic wallpaper?
I own the top model Luminous......3 in, 2 out, with remote ( single ended ), and I am very pleased with it's performance.
No.
Every contact, additional component and wire/trace affects the sound. Anything below -20dB is pointless with properly configured gain structure.

Is it HiFi or sonic wallpaper?


If it is contact less already on the signal path then you can have as many inputs as required, and zero volume too.

To do that arrange LDR anodes of each series pair to be switched on in turn - according with your stereo inputs. To zero volume needs your design to power shunt anode separate to series anode, it needs also NOT to ground the LDR cathodes, rather arrange a regulated  jfet current sink.

Your volume control is arranged between shunt cathode and series cathode.  You then arrange via LM317, with a higher potential on its adjustment terminal, place its Vin to the series cathodes and adjust for silence with resistance from the higher potential to Adj. As lower volume positions are reached, the start circuit thus named influences the series resistance readings, and causes extreme resistance on series pair at lowest volume, creating ability for silence. 

The start circuit is accompanied with another circuit called the continue together they interact together to improve relationship of the entire circuit for excellent current delivery and resulting audio performance.

   
testpilot636 posts04-10-2021 9:54pm@dbxrecords ....why not just disclose or post under your industry affiliation?
There’s only one reason he is here, to promote snake oil he makes.


georgehifi8,879 posts
NZ shysters!!!!!!!!!!!
Chris Daley? JAVA ldr passive preamplifier $3.5K!!!!!!

dbxrecord OP (aka Chris Daly)
I have no association with either name, please stick to the subject rather than libel.
How’s that for a outright lie!! How does he live with himself? Chris! you are certifiable.

From his Stereo Coffee website contact info https://ibb.co/hDwKkVV
and him preaching his snake oil at the NZ coffee shop Java ldr release. https://ibb.co/yqH11rj

Chris Daly has been criticize by some very knowledgeable electronic designers on many forums for his BS trying to get sales from the gullible, he’s even tried to claim the Lightspeed Attentuator, it’s about time he disappeared.

Cheers George
Please stick to the subject, rather than further libel,   the subject is

Are there passive attenuators that don't zero volume and only offer one input ?

I am not sure how many people would like those features, but its worth asking in case someone would try to sell such a thing.

Which is to say it is essential I should think to be able to zero volume, and have more than one input, do you agree ?



How’s that for a outright lie!! How does he live with himself? Chris! you are certifiable.


If you choose to spell my name wrongly, I have no obligation to agree to that mistake, I would expect you to do the same, not acknowledge your name being spelt wrongly - as would anyone.

Please once again,  stick to the subject. If you have nothing to contribute then don't contribute.

I can say, all my passive attenuators are able to zero volume, and I enjoy  6 contact less stereo inputs , that is if you need any further reminding of what the thread is about.  Just this morning I enjoyed radio on one input, then switched to a jazz CD, and to a hard disc recorder for some Pink Floyd, I did not have to change cables at all.


Just had a look @ OP Stereo Coffee LDR attenuator @ 
Stereo Coffee Passive LDR Preamplifier (wixsite.com)

Why an A/C supply when a DC wallwart would keep all hum outtadabox?

PCB looks like something a kid would have designed 40 years ago.

TRIM POTS?!?!?!? WTF? Trim pots are the bane of high fidelity.

"However, the real magic of the 2020 StereoCoffee is what happens after 40 to 50 minutes playing music."

If a passive is changing, it's not passive. The whole point, at least for me for 40+ years, is PASSIVES DO NOT CHANGE!!!

He a shyster ieales, and known all over other forums
All you have to do is see how he disowned his own name and product, in the proof I posted up.

This was the best one he tried to sell on ebay and diyaudio he called a "Pass Transistor opamps" https://ibb.co/Db3yj9s see the little smd transistor squashed under the opamp with the "snake oil" he tried on
https://www.head-fi.org/members/dbxrecord.192735/

Cheers George
Why an A/C supply when a DC wallwart would keep all hum outtadabox?
Because you then avoid the cheap rectification components inside wall warts, all avoided by using a AC 12v supply.  Rectification can then be achieved with thyristors, and jfets

https://www.stereo.net.au/forums/topic/113297-comparison-lightspeed-diy-ldr-pre-vs-stereo-coffee-diy...



See ieales BS baffles the gullible, that’s his game.

Cheers George

Rectification can then be achieved with thyristors, and jfets
¿Que?

Thyristor is a gated diode. What earthly advantage is there over a 1N400x diode?

High quality DC supplies are 10 a penny today.
High quality DC supplies are 10 a penny today.


 Look inside the plugpack  , it explains why they are 10 a penny.

"A thyristor is a semiconductor device which can be used to switch current on and off. When used in rectifier circuits, thyristors allow current to be controlled more accurately than diodes, which can only be ON or OFF. A thyristor can be triggered to allow current to pass in a graduated manner, by firing (switching on the thyristor) at a precise time, therefore controlling the conduction angle."
https://www.ppi-uk.com/news/thyristor-controlled-rectifiers/


@dbxrecord OP

Please deny again for the record

1: That you are Chris Daly
2: Have any associations with
a: Stereo Coffee
b: Java Preamps
c: Opamp Pass transistors
3: That this you https://ibb.co/yqH11rj
What about using those keyboard fingers instead, to design your product so that it can have more than one input, and can have silence at zero volume, ... a far better use of your time I should think.
Can't do it, because you are him!!!!
 
I am happy to ignore that reason, as  it has absolutely no relevance at all, relating to what customers want from passive attenuators.

We each know LDR passives offer so much better audio than other attenuation methods, and the task ahead is to make LDR passives the number one choice, as nothing else, can do what they do. 

The good news is each issue, namely more inputs and silence  are relatively easy to do.   I am very sure your customers will welcome those new features, and thank you,  for caring about their needs.,

on a wider perspective ... it will see see all other passives, .. eating dust.