Ok, than let us start.
Folks, please post your best circuits around the Lightspeed (power supplies, attenuator configurations, improvements ...)!
I think it is time for a little summary!
Folks, please post your best circuits around the Lightspeed (power supplies, attenuator configurations, improvements ...)!
I think it is time for a little summary!
and
As a lurker on this thread, and as one who would be interested in putting a lightspeed together at some point, may I suggest that this would be a good application for the (much under-used) wiki?
Regards.
Aengus
My guess is that anyone who has tried current regulation to power the LED's has preferred it and stayed with it.
I would be interested if this is true and how many have made this step.
Did anyone return to voltage regulation having tried current regulation ?
if we establish this we may have a good starting point
mike
I would be interested if this is true and how many have made this step.
Did anyone return to voltage regulation having tried current regulation ?
if we establish this we may have a good starting point
mike
The Wiki would be good.
I was thinking of going thru the thread and dividing the posts up into sections like "Ccts" (different designs), "Power supplies", "Testing methods" (of the LDRS, impedance, etc), "Buffers"(some repeats of some Ccts, no doubt), etc and adding ther post number to each and the relevant page, as there is a noticable lack of "attachment-moxie" here! (just can't get the darn things to work!).
Any suggestions? - saves time.
I was thinking of going thru the thread and dividing the posts up into sections like "Ccts" (different designs), "Power supplies", "Testing methods" (of the LDRS, impedance, etc), "Buffers"(some repeats of some Ccts, no doubt), etc and adding ther post number to each and the relevant page, as there is a noticable lack of "attachment-moxie" here! (just can't get the darn things to work!).
Any suggestions? - saves time.
I am using the Lightspeed using a low noise power supply to generate 5V.
I have seen reference to the use of a constant current source.
Where is the schematic/description of this?
I have seen reference to the use of a constant current source.
Where is the schematic/description of this?
Remote control for the Lightspeed
Hi Maximus,
I'm interested in your version of Lightspeed with remote control too. If you don't have PCB available, can you share the pcb's layout and the diagram circuits?
I'm running a SAC-DVD-A (Denon) with two solid state monoblocks of 500w in 4 Ohns, and always I have a big problem with pot noise and click, so I'm shure this is the solution.
Best Regards
Daniel
Hi Maximus,
I'm interested in your version of Lightspeed with remote control too. If you don't have PCB available, can you share the pcb's layout and the diagram circuits?
I'm running a SAC-DVD-A (Denon) with two solid state monoblocks of 500w in 4 Ohns, and always I have a big problem with pot noise and click, so I'm shure this is the solution.
Best Regards
Daniel
Hi
there is my prototype of DAC-controlled shunt regulated optocoupler attenuator. I have used two 16bit voltage output DACs that feed a 32SR2S coupler.
As you see it is on a very early state. The STK500 development board is on the left and the bread board on the right. I have use Vishay Dale CMF55-143 non-magnetic resistors as series resistor.
I have to do some listening sessions against MKII in order to hear what is better.
there is my prototype of DAC-controlled shunt regulated optocoupler attenuator. I have used two 16bit voltage output DACs that feed a 32SR2S coupler.
As you see it is on a very early state. The STK500 development board is on the left and the bread board on the right. I have use Vishay Dale CMF55-143 non-magnetic resistors as series resistor.
I have to do some listening sessions against MKII in order to hear what is better.
Attachments
Lightspeed remote control
Hi Daniel,
I am having a sheet of production prototype boards made next week and, as there was some space left on the sheet, I have included some lightspeed remote control boards to verify the circuit layout operates without problems. Once the board is verified I will get back to you.
Pot noise is not a problem with this circuit.
Regards
Paul
Hi Daniel,
I am having a sheet of production prototype boards made next week and, as there was some space left on the sheet, I have included some lightspeed remote control boards to verify the circuit layout operates without problems. Once the board is verified I will get back to you.
Pot noise is not a problem with this circuit.
Regards
Paul
DAC Lightspeed
Progress report:
The channel matching between L and R is < 0.1 dB what is one of my goals.
The sound: Not bad at all but series/shunt optocoupler is better. More live, more dynamics, wider stage, more headroom.
so, development keeps running ... next attempt: 4 DACs for 4 optocouplers! I think I have to buy more SR2S because there are only 5 left.
Who has a matched pair left over?
Progress report:
The channel matching between L and R is < 0.1 dB what is one of my goals.
The sound: Not bad at all but series/shunt optocoupler is better. More live, more dynamics, wider stage, more headroom.
so, development keeps running ... next attempt: 4 DACs for 4 optocouplers! I think I have to buy more SR2S because there are only 5 left.
Who has a matched pair left over?
For you few folks who have had a chance to listen to the stock version of Lightspeed and the one with a buffer. Any new comments. I have purchased the parts to make either the buffer or the stock unit and would like to know what you think. I will be putting this unit in my A-75 amp. Would it benefit from the buffer?
Tad
Tad
Just a quick post to say thanks for a great circuit.
I've build one myself now. I had a 20k motorised ALPS pot lying around, so wanted to use that. I'm running that with a regulated 3.3v supply and it works just great.
Put 470n caps across the diodes in the LDRs.
I'm running a balanced circuit - LDR in series with each signal line & an LDR shunt between the two signals. I bought 25 LDR's weeded out 2 pairs that were very closely matched for the series LDRS & 1 pair matched for the shunt.
Sound is very transparent, highly recommend this circuit.
I have 19 LDR's available with data, if anyone would like to contact me.
Cheers,
jason
I've build one myself now. I had a 20k motorised ALPS pot lying around, so wanted to use that. I'm running that with a regulated 3.3v supply and it works just great.
Put 470n caps across the diodes in the LDRs.
I'm running a balanced circuit - LDR in series with each signal line & an LDR shunt between the two signals. I bought 25 LDR's weeded out 2 pairs that were very closely matched for the series LDRS & 1 pair matched for the shunt.
Sound is very transparent, highly recommend this circuit.
I have 19 LDR's available with data, if anyone would like to contact me.
Cheers,
jason
digital volume control with optical devices
http://www.pns-tech.com/products.php
Does anyone knows whats inside or have schematics?
http://www.pns-tech.com/products.php
Does anyone knows whats inside or have schematics?
Re: digital volume control with optical devices
To be honest I thought I would have been the Chinese, that were going to rip me off, but the Koreans beat them to it.
I must say it is very nicely done and in typical Asian fashion, kit parts are available.
Well done (but I hate them for doing it) does anyone have any pricing on these?
Also Dartzel copied it, but in a much more expensive fashion http://www.diyaudio.com/forums/showthread.php?postid=1439012#post1439012
Cheers George
1543 said:
To be honest I thought I would have been the Chinese, that were going to rip me off, but the Koreans beat them to it.
I must say it is very nicely done and in typical Asian fashion, kit parts are available.
Well done (but I hate them for doing it) does anyone have any pricing on these?
Also Dartzel copied it, but in a much more expensive fashion http://www.diyaudio.com/forums/showthread.php?postid=1439012#post1439012
Cheers George
Not really cheap!
OPC271 Kit1 with controller, remote control and PS for controller => 765 Euro
Kit2 balanced version 1205 Euro
I have just finished my µController version of Silonex series/shunt version which is rather the same I think. It has attenuation between 0 and -72 dB with 1dB steps. But parts cost just around 70 Euro!
OPC271 Kit1 with controller, remote control and PS for controller => 765 Euro
Kit2 balanced version 1205 Euro
I have just finished my µController version of Silonex series/shunt version which is rather the same I think. It has attenuation between 0 and -72 dB with 1dB steps. But parts cost just around 70 Euro!
Tolu said:
That's great, makes my fully finished Lightspeed Attenuator look like a bargain at 500aud (259 Euro), although no remote.
Thanks Tolu you bought the smile back to my face.
Cheers George
Hi George
you haven't heard it. Perhaps you would smile more (or less🙂 )!
Why don't you make it remote-controlled? An 100k Alps pot and 5 additional parts for about 30 € and you can offer a R/C version with an additional charge of 100-150 AU$!
you haven't heard it. Perhaps you would smile more (or less🙂 )!
Why don't you make it remote-controlled? An 100k Alps pot and 5 additional parts for about 30 € and you can offer a R/C version with an additional charge of 100-150 AU$!
Double the cost of those parts here, receiver, remote, motorized pot and power supply, then add your margin, and you have something that is going to cost twice as much to the customer, and still sound the same, worse if input switching is used. In my opinion not the purest way of doing things.
Cheers George
Cheers George
Have you tried input switching with one optocoupler in series and a relais that switches ground in shunt configuration?
By the way, I am very 😀 with my new 4 DAC/optocoupler setup. R/C with -1dB steps and max. 0,1 dB channel mismatch.
It's a shame that the Silonex parts can't be used in the EU by high end firms because of WEEE and RoHS!!!
By the way, I am very 😀 with my new 4 DAC/optocoupler setup. R/C with -1dB steps and max. 0,1 dB channel mismatch.
It's a shame that the Silonex parts can't be used in the EU by high end firms because of WEEE and RoHS!!!