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Old 6th January 2012, 10:13 PM   #4361
udailey is offline udailey  United States
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NSL32SR2 needs nowhere near 20mA to hit lower than 40. Did it 12 times today with 12 different NSL32SR2 and only 10mA. The SR2 and SR2S are in fact the same device. After manufacturing some are bagged and some are matched at around 100R to 200R and if they are within 10% of each other they are given an 'S' badge and a letter indicating into which 10% between 100 and 200 they fell into. Also all on the datasheet. However my information does not come to me via the datasheet but from several discussions with the vice president of silonex and their quality control engineer. Obviously I have performed my own experiments on many of these devices. Around 9000 of them now.
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Old 6th January 2012, 10:49 PM   #4362
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Believe what you will, but these are the facts below, and are verified to me by Fred P. Rohrbacher V.P. & General Manager of Silonex a Casco Company, with who I've had many a email disscussion with over the last 6-7 years.
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File Type: jpg NSL32SR2.jpg (112.0 KB, 405 views)
File Type: jpg NSL32SR2S.jpg (117.7 KB, 391 views)
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Old 7th January 2012, 06:41 AM   #4363
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Quote:
Originally Posted by georgehifi View Post
...you will also get better logarithmic feel to the volume instead of nothing at the start till you get to 12 o'clock or too much at the start and can't get passed 8 o'clock...
Curious what you are talking about here. What do you mean when you say "you will get better logarithmic feel to the volume instead of nothing at the start til you get to 12 o'clock"?

I ask because a true logarithmic curve is exactly that. It's high attenuation for most of the entry ramp, then rapidly reduced attenuation past the halfway point. This is what log scale means. I must be misunderstanding you somehow.

What do you use for a volume control to drive the LDRs in your circuit?

Click the image to open in full size.
Logarithmic Scale
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Old 7th January 2012, 09:06 AM   #4364
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Exactly what it should be smooth and progressive from zero to 12o'clock then quickly accelerating the level from 12o'clock onwards. (logarithmic). That's what the matched NSL32SR2S quads do with a 100k dual log pot controling the 5vdc to the led's through 100ohm resistors.
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Old 7th January 2012, 10:21 AM   #4365
AndrewT is offline AndrewT  Scotland
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Originally Posted by georgehifi View Post
Andrew:

Like I have said all along more times than I care too now (to put it less diplomatically), you will get better lower levels if you use the NSL32SR2S, and when quad matched you will also get better logarithmic feel to the volume instead of nothing at the start till you get to 12 o'clock or too much at the start and can't get passed 8 o'clock. And also more stable impedances which I believe gives a better more consistant sound at different levels also, over the NSL32SR2 or the NSL32SR3. As you have typically 40ohms min value with the NSL32SR2S where the others have well over 100ohms and if anyone pushes these harder than 20mA you will over time end up with a dead led/ldr and that's a given.

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Where in there, is the data, to show that "Quad Matching" results in "Lower Minimum Volume"?

I am not referring to any of your other claims.
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Old 7th January 2012, 11:21 AM   #4366
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Andrew stop trying to twist things, you must have a serious weed up your ****. I stated in post 4358. "This is why I use quad matched sets of the NSL32SR2S, to get lower min volume to get better logarithmic feel to the volume and better channel balance."
The data shows the NSL32SR2S has a far lower typical impedance (40ohm) at 20mA led current than the NSL32SR2 or the NSL32SR3 which are over 100ohms typically.

Cheers George
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Old 7th January 2012, 11:30 AM   #4367
AndrewT is offline AndrewT  Scotland
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Georgehifi,


Since you have replied with 4posts since I asked about that claim, are you deliberately avoiding offering any justification for your claim that "Quad" matching "lowers the minimum volume"?

If you don't show how you have arrived at that, then I'll simply have to conclude that my first impression was correct. Quad matching does not lower minimum volume.
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Old 7th January 2012, 11:50 AM   #4368
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Must be Scottish Heather, read my statment again, it's the NSL32SR2S I'm refering to because it has a much lower "R on" resistance than the other two, go and take another shot of single malt, that Heather must hurt. ouch!!!!!!

Cheers George
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Old 7th January 2012, 08:09 PM   #4369
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Quote:
Originally Posted by georgehifi View Post
Exactly what it should be smooth and progressive from zero to 12o'clock then quickly accelerating the level from 12o'clock onwards. (logarithmic). That's what the matched NSL32SR2S quads do with a 100k dual log pot controling the 5vdc to the led's through 100ohm resistors.
I've never seen a log pot that produced that curve. All are approximations. It's not terrible, I mean, we've all happily lived with pots for years. But it just seems to me that if you're trying to get away from pots with the LDRs, well, then you would get away from pots.

Not to be nitpicky - I realize your goal is to keep the mechanical wiper out of the signal path. The actual curve of the pot is probably well less of an issue to you. But it does seem to me like part of the problem inherent with mechanical potentiometers is still there.
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Old 7th January 2012, 09:27 PM   #4370
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Originally Posted by Wayne Parham View Post
But it just seems to me that if you're trying to get away from pots with the LDRs, well, then you would get away from pots.
As you may/may not know the pot has nothing what so ever to do with the LDR's or the incoming or outgoing music signal, and with this design the sound quality has always come first.
All it's there for is to control the amount voltage going to the LED's in the simplest, cheapest most convenient manner, if you have a simpler way I'm all ears, KISS.

Cheers George
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