One other thing.... I tested a new circuit for a LDR based attenuator in the past few days. I get FULL use of my volume pot in this circuit. I am going to test a few more versions of it as I see a few possible improvements. I will say this right now though... It sounds better. Power supplies, to me anyway, do matter quite a bit. The supply is a simple linear supply. Center tapped Radio Shack 6.3-0-6.3 transformer followed by two snubbed diodes that converge to form one positive rail. Then on to double 1000uf snubbed electrolytics and on to a regulator. Thats it for the supply but the sound is better. You know how sometimes a voice can get loud and you hear a little grain to it at that point? This is gone and thats about all as far as improvements due to the supply, but its good enough for me and you might want to try it. Its a cheap and easy build. Another thing.... dont worry about voltage to these LDRs. 5V is a myth that has been busted as I was running them for over a day at 20V. I spoke with Fred Rohrbacher, the GM of Silonex, and he confirmed that the 5V is important as a limit for signal though the resistive cell but that it makes zero difference in any way over the LED except that we want to try to keep under 100mW fo power per LED. A nice thing about this is that if you have to high of impedance you can increase the value of your protective resistors and increase the voltage. Increase in voltage will create lower impedance and with increase in protective resistor you will still control current flow to LED and be able to set that current to a max that still allows a 40-50Ohm minimum resistance in the LDR.
Many people have said 5V is max for distortion. False. Pure dribble. The datasheet states that the distortion is related to the voltage across the CELL. The CELL is the photoresistive cell. I dont know when an LED has ever been referred to as a CELL but it there is still arguments about this please take your question to Fred at Silonex and you will find they are talking about the resistive cell and the signal's voltage, not voltage across the LED.
Uriah
Many people have said 5V is max for distortion. False. Pure dribble. The datasheet states that the distortion is related to the voltage across the CELL. The CELL is the photoresistive cell. I dont know when an LED has ever been referred to as a CELL but it there is still arguments about this please take your question to Fred at Silonex and you will find they are talking about the resistive cell and the signal's voltage, not voltage across the LED.
Uriah
LDR delivery
Uriah, LDRs arrived today. Cheers!! Re your post above, how much useage do you get from an existing LDR volume control eg from minimum volume position upto 11/12 o'clock? Just wondering whether it would be better to await the results of your experiments rather than diving right in. Thanks, Mark
Uriah, LDRs arrived today. Cheers!! Re your post above, how much useage do you get from an existing LDR volume control eg from minimum volume position upto 11/12 o'clock? Just wondering whether it would be better to await the results of your experiments rather than diving right in. Thanks, Mark
Puffin,
I suspect that with your postal strike over there it may take even longer. Yours have been in the mail as well as everyone else'. I apologize about the wait, I know it sucks. I am investing a very large amount in a new test fixture so that waiting is not a part of buying matched LDRs anymore. Boards for it should be here in a week. Hopefully it works like a charm.
Uriah
I suspect that with your postal strike over there it may take even longer. Yours have been in the mail as well as everyone else'. I apologize about the wait, I know it sucks. I am investing a very large amount in a new test fixture so that waiting is not a part of buying matched LDRs anymore. Boards for it should be here in a week. Hopefully it works like a charm.
Uriah
Puffin,
I was pretty sure you were just disappointed and not ticked. I didnt take it personally but rereading my response I do sound defensive. Sorry about that. The time it took to do this batch was much longer than I had intended and I am defensive even before anyone says anything.
I hope you get them soon.
Right now I am listening to a new circuit I worked out for controlling the LDRs. Its the best my system has ever sounded. Folks the power supply matters a lot here. I got it finished about two weeks ago but got satisfied with it this morning.
Linear supply is the way to go. A decent amount of capacitance is used. 2kuF. Snubbed all caps and diodes. Well I am not giving away the farm yet. Would like to get some boards and have a few of you try it out. The circuit after the supply is far different from the Lightspeed and while I dont know why it sounds better it does and all I was looking for was full pot rotation which I now have.
Uriah
I was pretty sure you were just disappointed and not ticked. I didnt take it personally but rereading my response I do sound defensive. Sorry about that. The time it took to do this batch was much longer than I had intended and I am defensive even before anyone says anything.
I hope you get them soon.
Right now I am listening to a new circuit I worked out for controlling the LDRs. Its the best my system has ever sounded. Folks the power supply matters a lot here. I got it finished about two weeks ago but got satisfied with it this morning.
Linear supply is the way to go. A decent amount of capacitance is used. 2kuF. Snubbed all caps and diodes. Well I am not giving away the farm yet. Would like to get some boards and have a few of you try it out. The circuit after the supply is far different from the Lightspeed and while I dont know why it sounds better it does and all I was looking for was full pot rotation which I now have.
Uriah
Puffin, great news!!! I am relieved...is there a wiping sweat smiley?
Uriah has the patience of Job, helping me to get set up...and then H1N1 flu hit us hard in September. What luck!!
Folks, as Uriah said, he's got a plan that should help us get through this process faster. My wrist was numb for 2 days measuring these little buggers!
But all international orders have shipped several days ago and Uriah and I will go off and have a well deserved beer.
Ohh, and here's my wife in October during the LDR testing...
I'm getting back on the Nordic Track so I'm in shape for next time! Enjoy the music!
Uriah has the patience of Job, helping me to get set up...and then H1N1 flu hit us hard in September. What luck!!
Folks, as Uriah said, he's got a plan that should help us get through this process faster. My wrist was numb for 2 days measuring these little buggers!
But all international orders have shipped several days ago and Uriah and I will go off and have a well deserved beer.
Ohh, and here's my wife in October during the LDR testing...
I'm getting back on the Nordic Track so I'm in shape for next time! Enjoy the music!
I am now waiting for Oliver's PCB to put it all together.
I have been using an LDR pre-amp using un-balanced LDR's to very good effect so it will be interesting to compare.
I got my board frfom Oliver today and have stuffed it with all but the LDR's
Uriah. The data supplied with the LDR's suggests that they are in two matched pairs. Do you know if they should be placed in pairs in the positions on Oliver's board?
Uriah. The data supplied with the LDR's suggests that they are in two matched pairs. Do you know if they should be placed in pairs in the positions on Oliver's board?
An externally hosted image should be here but it was not working when we last tested it.
Puffin
I am sure Oliver has a better understanding of his board than I do. Its twisting my head trying to follow from front to back and backwards.
BTW if there is any difference in your LDRs readings from one pair to the other pair use the lower values for shunt. Your volume will come on a little slower.
URiah
I am sure Oliver has a better understanding of his board than I do. Its twisting my head trying to follow from front to back and backwards.
BTW if there is any difference in your LDRs readings from one pair to the other pair use the lower values for shunt. Your volume will come on a little slower.
URiah
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