LDR photoresistor attenuator preamp, in general - Page 6 - diyAudio
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Old 21st February 2011, 11:36 AM   #51
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Default a comparision.......

Hi all,
I built a LDR series shunt,a 1% resistive ladder switch ,and a used a vishay 1% resistor,Now I replaced my volume controls with each one and played the same song same levels and listened,no test equipment other than my ears,lol 2 big floppie ones,
Results,I could tell a difference between the resistor and the ladder ,maybe contacts? in the ladder,sonics were different a little closed in,ok.
The ldr's I have one (set) series ,shunt per side,I like 2 volume controls one for each channel, I do hear better highs,midrange is more open and I did notice a bass increase,IF thier is distortion in this setup It's ok! It sounds good to me,I can't silence the volume but it's low enought to be a background when I'm doing other things.
I have a display with db's into active 3way system into gain clone amps,no special caps or resistors,or power supplies,maybe These change later ,but for now I listen for a while !
My audiences like the system so I am not trying to upset anyone's opinion this is only mine and my 2 cents,but I like the LDR improvement for now.
I have listen to some very expensive equipment, I live in a large city,
lots of high end stereo stores here,I'll stick with building from this GREAT site,
I come out alot better and cheaper!
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Old 21st February 2011, 11:43 AM   #52
AndrewT is offline AndrewT  Scotland
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one can use a stepped attenuator to send control currents to the LDRs. This can be trimmed at every step to ensure balance throughout the whole range of steps.

The stepped attenuator also allows experimentation with a very wide range of control currents, thus achieving small steps in volume adjustment wherever in the volume range you need small steps and can achieve accurate balance at very high attenuation levels.
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regards Andrew T.
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Old 21st February 2011, 11:48 AM   #53
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Default good Idea

hi Andrew T,
I didn't think of that but I will try it and see how it works,
Thanks
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Old 13th December 2013, 09:39 AM   #54
mikelm is offline mikelm  England
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Quote:
Originally Posted by dave slagle View Post
The output Z of a resistive attenuator changes with attenuation setting.
A voice of sanity in the midst of confusion.

Did everyone get that this applies to LDRs just in much the same way as any other resistive pot ?

Just the shape of the curve will be different.
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Old 14th December 2013, 03:32 AM   #55
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I decided to take a shot at making a ldr,so far so good ,I made some with just a drop of SG and the led to the photocell,it works better to flatten the tip of the led ,the whole assembly fits better,I checked the 2 I had made up and they were exactly the same, I made the circuit to test and only changed the ldr when testing,I made 4 more I will test and try them out tomorrow,BTW I cover the LDR when testing,when I finish them I will cover them with Black heat shrink and blk tape if the shrink bleeds light.
I found these parts on ebay 50 photocell $7.00 and 100 White LED's /resistors were $4.00. I did find some after I bought these that have a flat top,lol,my luck!
so if they hit 20 cents it's a keeper,
I like the test circuit I think Nelson put that up for us,THANKS ! I used push on monetary switches ,as all the rotary I had on hand where 1 to 6 ers,lol.
I am thinking about a touch up down control for these anyone made one yet?
Regards,
NS
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Last edited by noSmoking; 14th December 2013 at 03:39 AM. Reason: added some
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