theophile said:
Yeah got my eye on it, prime candidate for a Lightspeed transplant, if you want an active "tube buffer" Lightspeed Attenuator. I even have the circuit diagram for it "what a mess." In A/B comparisons I've done, the standard Lightspeed Attenuator I make sounds more open, just doesn't look as good or has the big $ tag.
The original "Photopotentiomer" they used was a nightmare, nearly all failed and lost channel balance.
The "SHA Gold Reference" is even better as it was a multi box unit, very expensive 20k odd, but it had the same problems with the LDR's in the "Photopotentiomer".
Cheers George
Attachments
George,I just thought I'd let you know that I have been listening to the Lightspeed minus the Burson buffer,since Six O'clock this morning.
There was an unmistakable increase in low-level detail,maybe a little less(it isn't gross)impact in the bass with a slight perception of increased brightness(again not gross).
I like the increase in low-level detail.
I'll leave things as they are(Buffer bypassed)for a while and let this thing 'simmer'.
I'm not getting the problems I initially had when I first put the LS into my system.I am however using different interconnects and the Accuphase active crossover,no longer using the Behringer active crossover.
There was an unmistakable increase in low-level detail,maybe a little less(it isn't gross)impact in the bass with a slight perception of increased brightness(again not gross).
I like the increase in low-level detail.
I'll leave things as they are(Buffer bypassed)for a while and let this thing 'simmer'.
I'm not getting the problems I initially had when I first put the LS into my system.I am however using different interconnects and the Accuphase active crossover,no longer using the Behringer active crossover.
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I am in the process of building a 5 (maybe 6) channel HT amplifier. I will need a volume control on the front end. So I was very interested to come across this thread. But matching enough LDRs for this many channels sounds like a non-starter from what I've read here. Some compromises will have to be made in my case. I'm wondering what these should be ?
For example, if I use a fixed resistor for the shunt and LDRs for the series then I only have to match between channels 1 LDR each. Of course it means that the impedance of the thing varies with volume - what are the consequences of this ?
For example, if I use a fixed resistor for the shunt and LDRs for the series then I only have to match between channels 1 LDR each. Of course it means that the impedance of the thing varies with volume - what are the consequences of this ?
You could put a pot on each one of them and turn each individually, but I think 5 channels is likely a pain in the you know what. However, this thing is the nicest sounding pot I have EVER heard and theres a hundred pages behind this one saying the same thing.
You shunt idea would, yes mess with the impedance, but this might be fine depending if your amps could handle the high and low of the impedance. It would probably sound better than your average pot, but many have commented on how both being LDRs sounds better than that option. However, if you go matching this will be by far your easiest solution and if you buy 30 or so you probably will get the 5 you need or at least 4 and then you could adjust your sub accordingly.
Uriah
You shunt idea would, yes mess with the impedance, but this might be fine depending if your amps could handle the high and low of the impedance. It would probably sound better than your average pot, but many have commented on how both being LDRs sounds better than that option. However, if you go matching this will be by far your easiest solution and if you buy 30 or so you probably will get the 5 you need or at least 4 and then you could adjust your sub accordingly.
Uriah
udailey said:
Uriah,
I really didn't do anything.
I suspect that the troubles I was having previously,were all related to the interconnects I was using with my Behringer active crossover.
I intend to listen without the Buffer for a couple of weeks,then reconnect the Buffer,just to reconfirm my impression of with/without.
I have no doubt that George is correct that in absolute terms,the Lightspeed should be used without a Buffer in order to realise it's full potential.However in some installations a Buffer would be mandatory.
The full realisation of the Lightspeed's potential is dependent upon other factors being present within the system in which it is used.
My previous set-up(with it's interconnects)was not sympathetic.My current one is much more so.
Another older review of the DartZeel NHB-18ns in Stereophile
A quote from it:
" The proprietary volume, or Enjoyment, control uses no contacts, relays, switches, or silicon devices. DarTZeel isn't talking about its exact methodology, saying only that "some light is involved."
http://stereophile.com/solidpreamps/607dart/
And the review of the DartZeel NHB-18ns from 6 Moons
A quote from it:
Part of the Herve Deletraz interview on the Dartzeel
Q: What is wrong with conventional volume controls?
A: You lose something. I use a system that varies resistance with light. However, until all the patents are in place, I would prefer not to specify the details.
Last page half way down of the Hervé Delétraz Interview
http://www.6moons.com/audioreviews/dartzeel2/preamp.html
Cheers George
A quote from it:
" The proprietary volume, or Enjoyment, control uses no contacts, relays, switches, or silicon devices. DarTZeel isn't talking about its exact methodology, saying only that "some light is involved."
http://stereophile.com/solidpreamps/607dart/
And the review of the DartZeel NHB-18ns from 6 Moons
A quote from it:
Part of the Herve Deletraz interview on the Dartzeel
Q: What is wrong with conventional volume controls?
A: You lose something. I use a system that varies resistance with light. However, until all the patents are in place, I would prefer not to specify the details.
Last page half way down of the Hervé Delétraz Interview
http://www.6moons.com/audioreviews/dartzeel2/preamp.html
Cheers George
DARTZEEL Amplifier -- you'll find a schematic somewhere in there
http://www.dartzeel.com/PDF_Files/AudioManuEN.pdf
http://www.dartzeel.com/PDF_Files/AudioManuEN.pdf
resistance range..
I got 16 SR2S LDR and tried to match it. In my setup 5V 300ma regulated PS, 100k ohm log pot, 100 ohm resistor like LS, I found the range is 35 ohm to at most 2k Ohm from the LDR. It is a bit low comparing to the people posted in the board. I checked the pot and I can read 2ohm to 96k ohm so it is okay. I even tried a 100kOhm resistor in series and found all 16 SR2S all read at most 2k ohm in this setting. I am lost here. Are the recent sorted (mine is R2A) LDRs have different characteristics than before. I need to use a 250k Ohm pot to get 7k ohm resistance out from the LDR. If someone have bought some LDRs recently, can you show me your reading at 20uA, 10uA and 1mA? If I use this 100k pot I can only get at most 36db attenuation...which is too loud for my setup at this setting.
Philip
I got 16 SR2S LDR and tried to match it. In my setup 5V 300ma regulated PS, 100k ohm log pot, 100 ohm resistor like LS, I found the range is 35 ohm to at most 2k Ohm from the LDR. It is a bit low comparing to the people posted in the board. I checked the pot and I can read 2ohm to 96k ohm so it is okay. I even tried a 100kOhm resistor in series and found all 16 SR2S all read at most 2k ohm in this setting. I am lost here. Are the recent sorted (mine is R2A) LDRs have different characteristics than before. I need to use a 250k Ohm pot to get 7k ohm resistance out from the LDR. If someone have bought some LDRs recently, can you show me your reading at 20uA, 10uA and 1mA? If I use this 100k pot I can only get at most 36db attenuation...which is too loud for my setup at this setting.
Philip
At 40k on one of my tests I have resistance from 1.2k (actually some real duds were much lower) to as high as one went to 26k. Real weird. Seemed like the ones with the same date would track closer to each other than even the sorted. If anyone buys a bunch to test, sorted is NOT an advantage. They will send you some with the letters A-H on them. So what? You are going to test them anyway, right? So whats the point in sorted? Plus their sorting system is terrible. They apply voltage for a few seconds and read the resistance, then from that resistance they catagorize it A-H. These things dont come close to settling for several minutes and then slowly settle totally in 10-20 minutes.
My average at 40k was probably in 3-3.5k and if you take that LDR up to 100k you will get something much more. I took a 1.3k up to 100k just for kicks and got 6.25k out of it. Now I have to run through all my 1.2k and similar resistors to see if I have some matches that might work better than I had though. If you want to email me we can talk about how you tested them and see if there was a mistake somewhere.
I think your 16 are better than you are thinking at least it just doesnt make sense to me that they would rate that low, but then again... look at the numbers on the side. Might be 408 or 109 or similar. If they are mostly all the same you might have got a junk date. Out of 300 I am not using over 100 so either my standards are to high or their manufacturing process stinks.
Uriah
My average at 40k was probably in 3-3.5k and if you take that LDR up to 100k you will get something much more. I took a 1.3k up to 100k just for kicks and got 6.25k out of it. Now I have to run through all my 1.2k and similar resistors to see if I have some matches that might work better than I had though. If you want to email me we can talk about how you tested them and see if there was a mistake somewhere.
I think your 16 are better than you are thinking at least it just doesnt make sense to me that they would rate that low, but then again... look at the numbers on the side. Might be 408 or 109 or similar. If they are mostly all the same you might have got a junk date. Out of 300 I am not using over 100 so either my standards are to high or their manufacturing process stinks.
Uriah
udailey said:
This does then beg the question - In operation as a vol control does it take this time for the volume to settle down when changed - I'm obviously wrong as this wouldn't work in practise so what am I missing?
I wrote to Silonex a while ago about their matching & they replied that they could not guarantee sorted parts from the same grade would be supplied through their distributors. They failed to respond to the following observation:udailey said:
Edit: Are you guys getting parts with the same grade letter? Uriah 33% scrappage is a low yield. I just got your package, thank you - i don't see any grade letter on the parts?
Thank Uriah!
My date is 408, R2A batch sorted. They are very consistent at 20uA setting (100k pot position) around 2k ohm. I also have some dated 408 non-sorted 2 months ago and they have around 7k ohm at the same current setting. At least they are consistent...and I just need a 250k pot to get to 7k ohm impedance to get 46db attenuation. So most people got 7kohm at 20uA setting...only me I got around 2k ohm in my sorted LDR...weird...
Any more people have different value at 100k pot position from their LDR?
I am going to assemble LS using a 250k pot to get 46db attenuation.
Philip
My date is 408, R2A batch sorted. They are very consistent at 20uA setting (100k pot position) around 2k ohm. I also have some dated 408 non-sorted 2 months ago and they have around 7k ohm at the same current setting. At least they are consistent...and I just need a 250k pot to get to 7k ohm impedance to get 46db attenuation. So most people got 7kohm at 20uA setting...only me I got around 2k ohm in my sorted LDR...weird...
Any more people have different value at 100k pot position from their LDR?
I am going to assemble LS using a 250k pot to get 46db attenuation.
Philip
jackinnj said:
Quote from the user manual, use the link below
Quote: Our proprietary volume control involves a very new
approach, never achieved before: no any contacts,
relays, switches or silicon devices are used. The
delicate sound then remains untouched, for your
greatest pleasure, so the reason why we did not
write “Volume” on the front plate, but simply
Pleasure Control… The way we do it is still a bit
confidential at the moment; we just can say that
some light is involved in the control. Quote:
These guys need to be told the idea is over 30 years old!
http://www.dartzeel.com/PDF_Files/preliminary_usermanual_phono_v093_en.pdf
Cheers George
George,
I decided to try a record which I know has really nice bass on it(Yes 'Fragile' UK pressing).
I at first got very nice sound,but with a channel imbalance.I decided to swap the interconnects from my Simaudio Moon LP5.3 phono stage around(this is the source which is feeding the Lightspeed)at the Lightspeed inputs.
OH MY GOD ! ! !
No more channel imbalance.What a sound !!!
OH MY GOD ! ! !
Forget about bass lightness.
OH MY GOD ! ! !
I've never really heard the Lightspeed before(obviously)despite owning it for 15 months now....
GET RID OF THE BUFFER ! ! !
Go back to active preamp?
YOU MUST BE JOKING ! ! !
Thanks George for giving us this brilliant piece of equipment.
PS is there any documentary proof you have to stifle Dartzeels attempt to patent this thing?
I realise that you have individuals who can attest to your using the LDRs for 30 years,but you need to get some evidence and stop those pricks from claiming that they invented the wheel.
I decided to try a record which I know has really nice bass on it(Yes 'Fragile' UK pressing).
I at first got very nice sound,but with a channel imbalance.I decided to swap the interconnects from my Simaudio Moon LP5.3 phono stage around(this is the source which is feeding the Lightspeed)at the Lightspeed inputs.
OH MY GOD ! ! !
No more channel imbalance.What a sound !!!
OH MY GOD ! ! !
Forget about bass lightness.
OH MY GOD ! ! !
I've never really heard the Lightspeed before(obviously)despite owning it for 15 months now....
GET RID OF THE BUFFER ! ! !
Go back to active preamp?
YOU MUST BE JOKING ! ! !
Thanks George for giving us this brilliant piece of equipment.
PS is there any documentary proof you have to stifle Dartzeels attempt to patent this thing?
I realise that you have individuals who can attest to your using the LDRs for 30 years,but you need to get some evidence and stop those pricks from claiming that they invented the wheel.
theophile said:
I've already sent a while back the US/European Patent offices proof that I started it (MkI) over 30 years ago, and shown them details of my current production Lightspeed Attenuator MkII which started over 5 years ago, I think now you will see that the Dartzeel Patent Pending will not get granted a Patent for "very new approach" pot that works with light.
And congrats on getting the records to so so good. Like I've always said, "the best buffer is no buffer".
And regarding your changing of interconnects, the chassis RCA sockets that I use on the production Lightspeed Attenuator are now the new safety type which make earth contact before center pin, what this means is that some of the older RCA plugs on interconnects have a center pin that is TOO short to make a good contact inside the chassis RCA socket, this may have been your channel imbalance problem "a high resistance contact" I've struck this a few times now.
Cheers George
Lightspeed remote control
Hi Troy and everyone in the group buy,
The VCCS boards have arrived. I will be populating and testing one over the next few days to verify that I haven't made any layout errors. Once verified I will finish the application notes and ship the VCCS board orders. This will probably be next week. VCCS modules will be prepared and shipped over the following few weeks.
I am expecting the infra red transmitter and receiver boards early next week. The same process will apply.
Some of you have ordered both VCCS and IR boards/modules and these will be shipped together once all are ready as this saves on the individual carriage prices. Unless, of course you are in a hurry to get started, in which case I will get the VCCS boards/modules out straight away. This will incur the the individual item carriage charge for each board/module so you would have to forward this additional carriage charge to allow me to ship the IR boards/modules separately.
Regards
Paul
Hi Troy and everyone in the group buy,
The VCCS boards have arrived. I will be populating and testing one over the next few days to verify that I haven't made any layout errors. Once verified I will finish the application notes and ship the VCCS board orders. This will probably be next week. VCCS modules will be prepared and shipped over the following few weeks.
I am expecting the infra red transmitter and receiver boards early next week. The same process will apply.
Some of you have ordered both VCCS and IR boards/modules and these will be shipped together once all are ready as this saves on the individual carriage prices. Unless, of course you are in a hurry to get started, in which case I will get the VCCS boards/modules out straight away. This will incur the the individual item carriage charge for each board/module so you would have to forward this additional carriage charge to allow me to ship the IR boards/modules separately.
Regards
Paul