solution to those who say that LED's affect the sound adversely

elizard · 8th June 2003, 01:04 AM

Well, after looking over some (quite a few) threads, and reading all sorts of claims of how LED's (i.e. high-brightness blue ones) affect the sound when the power for them is taken from the rails, i decided to find a sensible solution:

well, one was additional transformer/additional winding for a transformer which peter employs .. but i don't feel like breaking the potting of my toroid, and i don't have space for another small transformer ..

so ...
batteries came to mind, 9V specifically

well, i had no 9V batteries lying around, so i picked up a 1.5V (AA? .. or AAA? in any case, A of a sort!) and the LED doesn't work (not enough voltage) ..
two of them work though

no diodes needed, no resistors (in my case, the led is bright but doesn't light up the room .. although it IS still light outside, so i may need to re-evaluate that decision when the sun sets) needed .. and i have a bright red LED on my gainclone supply w/o it effecting the sound at all

btw, for this to work, you can't use a spst switch .. dpst/dpdt is required so that the LED lights up when you press the switch

elizard · 8th June 2003, 01:06 AM

oh yeah .. the thread title should be "... adversely affect the sound"

i think .. that sounds right

jackinnj · 8th June 2003, 01:08 AM

as a birthday candle held near your preamp.

elizard · 8th June 2003, 01:16 AM

well the birthday candle will eminate some heat, which will warm up your preamp more so at the spot you're holding the candle at, and therefore totally throw off the sound!
especially if you're leaning towards left/right channel and less towards the other

theChris · 8th June 2003, 01:19 AM

hmm, i often lean to the left and right at the same time...

any info on the current draw with 2 AA batteries?

elizard · 8th June 2003, 01:39 AM

no clue, sorry ..

the LED's are rated 20mA .. now I've seen one light up at 20mA .. and um, then i fried it shortly thereafter

it seems its about 1/2-2/3 of its brightness .. and its getting to be pretty dark as the sun is starting to set .. although i'll be able to tell when its fully dark in about 2-3 hours ..

Steve Eddy · 8th June 2003, 01:41 AM

Quote:

Originally posted by theChris
any info on the current draw with 2 AA batteries?

Well, it will be the total voltage of the two batteries minus the forward voltage drop of the LED divided by the total series resistance of the two batteries.

You could probably get away with a bit of additional resistance (i.e. a resistor) and prolong the battery life.

se

elizard · 8th June 2003, 01:43 AM

well the setup i did with the 2AA batteries is just a temporary one to test and see if it works, and if it does, how well

when it runs out i'm going to use a 9V battery, and DEFINITELY a resistor .. probably around 1k should cut it and still be plenty bright ..

Steve Eddy · 8th June 2003, 02:10 AM

Quote:

Originally posted by elizard
well the setup i did with the 2AA batteries is just a temporary one to test and see if it works, and if it does, how well

when it runs out i'm going to use a 9V battery, and DEFINITELY a resistor .. probably around 1k should cut it and still be plenty bright ..

Yeah, that'll work. Though you could also just get a little AA battery holder at Radio Shack and stick with the AAs. I was just playing around here with a pair of Duracell AAs and some LEDs with a 3 volt V<sub>F</sub> and even with a 68 ohm resistor I got sufficient brightness.

se

analog_sa · 8th June 2003, 08:17 AM

As someone with absolutely no interest in LEDs (or birthday candles) i wonder why don't you just put a few turns of wire on top of your toroid and get the led supplied from there.

8th June 2003, 01:04 AM	#1
elizard diyAudio Member Join Date: Mar 2003 Location: Winnipeg, MB	solution to those who say that LED's affect the sound adversely Well, after looking over some (quite a few) threads, and reading all sorts of claims of how LED's (i.e. high-brightness blue ones) affect the sound when the power for them is taken from the rails, i decided to find a sensible solution: well, one was additional transformer/additional winding for a transformer which peter employs .. but i don't feel like breaking the potting of my toroid, and i don't have space for another small transformer .. so ... batteries came to mind, 9V specifically well, i had no 9V batteries lying around, so i picked up a 1.5V (AA? .. or AAA? in any case, A of a sort!) and the LED doesn't work (not enough voltage) .. two of them work though no diodes needed, no resistors (in my case, the led is bright but doesn't light up the room .. although it IS still light outside, so i may need to re-evaluate that decision when the sun sets) needed .. and i have a bright red LED on my gainclone supply w/o it effecting the sound at all btw, for this to work, you can't use a spst switch .. dpst/dpdt is required so that the LED lights up when you press the switch

8th June 2003, 01:08 AM	#3
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	A led should have the same effect as a birthday candle held near your preamp.

8th June 2003, 01:19 AM	#5
theChris diyAudio Member Join Date: Dec 2001 Location: SIUE, Illinois, USA	hmm, i often lean to the left and right at the same time... any info on the current draw with 2 AA batteries? __________________ if only it could be used for good, not evil...

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Would this tear in the driver affect sound? (pic inside)	wixy	Multi-Way	1	6th January 2007 07:41 AM
Will routing edges of front baffle affect sound?	Ken C	Multi-Way	12	3rd December 2004 08:57 AM
Can a power cord affect sound quality??	sully	Parts	103	13th November 2003 02:23 PM
does the resistor's ppm affect the sound?	mekanoplastik	Parts	9	4th June 2003 04:21 AM


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

8th June 2003, 01:06 AM	#2
elizard diyAudio Member Join Date: Mar 2003 Location: Winnipeg, MB	oh yeah .. the thread title should be "... adversely affect the sound" i think .. that sounds right

8th June 2003, 01:16 AM	#4
elizard diyAudio Member Join Date: Mar 2003 Location: Winnipeg, MB	well the birthday candle will eminate some heat, which will warm up your preamp more so at the spot you're holding the candle at, and therefore totally throw off the sound! especially if you're leaning towards left/right channel and less towards the other

8th June 2003, 01:39 AM	#6
elizard diyAudio Member Join Date: Mar 2003 Location: Winnipeg, MB	no clue, sorry .. the LED's are rated 20mA .. now I've seen one light up at 20mA .. and um, then i fried it shortly thereafter it seems its about 1/2-2/3 of its brightness .. and its getting to be pretty dark as the sun is starting to set .. although i'll be able to tell when its fully dark in about 2-3 hours ..

8th June 2003, 01:43 AM	#8
elizard diyAudio Member Join Date: Mar 2003 Location: Winnipeg, MB	well the setup i did with the 2AA batteries is just a temporary one to test and see if it works, and if it does, how well when it runs out i'm going to use a 9V battery, and DEFINITELY a resistor .. probably around 1k should cut it and still be plenty bright ..

8th June 2003, 08:17 AM	#10
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	As someone with absolutely no interest in LEDs (or birthday candles) i wonder why don't you just put a few turns of wire on top of your toroid and get the led supplied from there.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read