Hi,
i tried a blue LED at 20mA, simple AB test, small sound improvement: a little more room, more relaxed feeling...(could be psycho effect, so who tried it also??)
I used green leds for many years for the same thing in my old player, but i think to compare green/red/blue/IR LEDs and a small bulb for wideband spectrum to see, which gives most improvement;
tried also the green-colour paint-game and the freezing CD, sound changes are at the same level as with leds, id say;
alf
i tried a blue LED at 20mA, simple AB test, small sound improvement: a little more room, more relaxed feeling...(could be psycho effect, so who tried it also??)
I used green leds for many years for the same thing in my old player, but i think to compare green/red/blue/IR LEDs and a small bulb for wideband spectrum to see, which gives most improvement;
tried also the green-colour paint-game and the freezing CD, sound changes are at the same level as with leds, id say;
alf
Tried the Blue LED and....
Ok, with my Blue LED in hand I went home and pulled apart one of my CD players. Placed the LED just under the Trans. placed the cover back on and powered it up (Blue LED with a 1k res. on a 12v external supply...cont. by a micro spring loaded switch). I first let everything warm up...good 2 1/2 hours (Luxman MQ-360 amp, Luxman C-05 pre, Luxman D113 CD and an Alpine 3900 DAC played through some home brew speakers). Yes I like Luxman. Played some music (Fleetwood...Rumors) listed to what it sounded like, then turned the LED on. Right away I could here that something had changed. Turned the LED off, again the sound changed. Is the sound better I asked myself...don't know...I am the person with the switch so maybe it's all in my head. I get my brother and tell him what I'm trying to do. He takes a seat and listens to the system...first with the LED off. I don't tell him when I'm turning the power on. As soon as I hit the switch...he tells me I just did something. Ok, he noticed it, he keeps listening while I turn the LED on and off...again he tells me every time the LED is on or off (held the switch behind my back the whole time). I ask if the sound is better...he tells me that to him the back ground music becomes "more free and easy" and the sound stage is "higher". Well, at this point I grab my cousin (who happens to be visiting at the time). Sit him down and start the process over. He tells me the same...switch on, switch Off. The sound to him is "more open".
So, did this LED make things better...yes and no. Yes in the fact that my test people liked the change...but did they really like the change, or just notice the change. To me, I think I am on the fence here...some songs I liked the change. Others, I didn't notice it. But is this sound really better. Or is it adding some kind of distortion, translating into frequencies that are a little more pleasing to the ear?
If you feel like trying something new...it's only a few dollars worth of parts, try it and make your own des.
I myself will try a Green LED and see to what happens.
Rino Odorico
Ok, with my Blue LED in hand I went home and pulled apart one of my CD players. Placed the LED just under the Trans. placed the cover back on and powered it up (Blue LED with a 1k res. on a 12v external supply...cont. by a micro spring loaded switch). I first let everything warm up...good 2 1/2 hours (Luxman MQ-360 amp, Luxman C-05 pre, Luxman D113 CD and an Alpine 3900 DAC played through some home brew speakers). Yes I like Luxman. Played some music (Fleetwood...Rumors) listed to what it sounded like, then turned the LED on. Right away I could here that something had changed. Turned the LED off, again the sound changed. Is the sound better I asked myself...don't know...I am the person with the switch so maybe it's all in my head. I get my brother and tell him what I'm trying to do. He takes a seat and listens to the system...first with the LED off. I don't tell him when I'm turning the power on. As soon as I hit the switch...he tells me I just did something. Ok, he noticed it, he keeps listening while I turn the LED on and off...again he tells me every time the LED is on or off (held the switch behind my back the whole time). I ask if the sound is better...he tells me that to him the back ground music becomes "more free and easy" and the sound stage is "higher". Well, at this point I grab my cousin (who happens to be visiting at the time). Sit him down and start the process over. He tells me the same...switch on, switch Off. The sound to him is "more open".
So, did this LED make things better...yes and no. Yes in the fact that my test people liked the change...but did they really like the change, or just notice the change. To me, I think I am on the fence here...some songs I liked the change. Others, I didn't notice it. But is this sound really better. Or is it adding some kind of distortion, translating into frequencies that are a little more pleasing to the ear?
If you feel like trying something new...it's only a few dollars worth of parts, try it and make your own des.
I myself will try a Green LED and see to what happens.
Rino Odorico
Peter Daniel said:
Hi Peter,
Wanted to jump in here.
In the digital domain the LSB is no weaker or stronger than any other bit. They are all either 1's or 0's and all are equally effected by any systemic environmental changes (like a blue LED). The binary value of the bits in a serial data stream is just as arbitrary as the order of the letters of the alphabet. The letter 'A' is no stronger or weaker than the letter 'Z'.
Adding noise to an analog signal prior to converting it to a digital value can have the effect of reducing quantization noise (also is done in the digital domain when converting sample rates). This is a real and sometimes useful technigue for squeezing all of the resolution possible out of an A/D converter. But, I don't understand how adding noise to the process of reading the digital data from a CD could have this same effect (which seems to be the basic argument presented in the articles).
In my opinion, this is where Christer was coming from in his comments about synchronising the LED light with the LSB. This would have to be happening for the blue LED to be limiting it's effects to only the LSB. If the LED is actually effecting the bit error rate then it is just as likely to effect the MSB would if uncorrected would result in huge signal errors (pops, etc).
I agree with Christer, this particular explaination lacks rigor. I wonder what else might be happening instead?
Perhaps the intent is to overload the error detection/correction process with too many errors to correct, but I would expect the result of this would be no data output rather than improved sonic qualities.
Perhaps this reduction in data output is the intended effect, very short gaps in the data resulting in no change in the D/A output for short periods of time? This would tend to result in a reduction in high frequency content of the audio output which might be pleasing for some recordings. I have not played with DAC's sufficiently to know if this is how they behave during short gaps in data. Comments anyone? I expect that if this is the mechanism at work then the specifics of your DAC would strongly influency what doing this sounds like.
It would be easy to test for this effect. You would need a CD with Pink noise and an RTA or spectrum analyzer. If the Blue LED is in fact reducing the high frequency response of the CD then you should be able to see the effects on the RTA.
Actually that is probably a valid test to try even if my speculation about a possible mechanism is wrong (which is probable). A change in the frequency response of the CD transport would absolutely show that the Blue LED is doing something to the sound. A 1dB change in level at higher frequencies would certainly be audible to most people.
Phil
Hi Peter,
I hadn't read Steve's posts about monitoring the C2 pin of the decoder for errors (told you I wasn't a DAC expert). This would be even easier than my RTA experiment, just hook up a counter to this pin (or even just a low pass filter and a voltmeter).
This would be a good experiment to see if increasing the bit error rate is behind the effects people are reporting.
Phil
I hadn't read Steve's posts about monitoring the C2 pin of the decoder for errors (told you I wasn't a DAC expert). This would be even easier than my RTA experiment, just hook up a counter to this pin (or even just a low pass filter and a voltmeter).
This would be a good experiment to see if increasing the bit error rate is behind the effects people are reporting.
Phil
Haldor
Haldor, I'll try your test theory this weekend. Should be interesting! If it does in fact pick up a change, that would be very interesting. The only problem I see with this is my test RTA...she will not read in half dB steps. Only single dB steps, and I'm almost shure that the change in sound is less than a dB in amplitude.
No matter, still going to exp. with this.
Rino Odorico
Haldor, I'll try your test theory this weekend. Should be interesting! If it does in fact pick up a change, that would be very interesting. The only problem I see with this is my test RTA...she will not read in half dB steps. Only single dB steps, and I'm almost shure that the change in sound is less than a dB in amplitude.
No matter, still going to exp. with this.
Rino Odorico
One important fact: there are no pcm-data errors at all (exept a cd is damaged), the c1 errors are random on allmost every cd, but after correction : no errors at all. thats it. I have leds to monitor c1 and c2 errors (since many years). Did you ever look at the analog signal coming from the pickup? low signal and a lot of noise... All changes to the sound happen in a different jitter modulation, and this is really difficult to fix; sound improves also, when the pickup is perfect adjusted, or the laser power is increased...or vibration of the player is reduced.
alf
alf
About 8-9 years ago, inspired by Krell, I mounted circle of 15 green LEDs around philips CDM4 transport (the tray loader was extracted) in my heavily modified Technics SLP202A player. At first I didn't like the change (but change it was) - the sound was harsh, metallic and bright. Then I installed pot to be able to adjust brightness of LEDs and voila - with the right amount of light the sound was smoother and with better soundstage definition then without LEDs, add to much light and the sound became worse. I even wrote letter about it (and other modifications in my CDP) to Audio Amateur magazine which got me 6 month subscription bonus 
.
Funny thing is that Technics is still working - maybe the LEDs have some positive effect on laser diode life ?
.Funny thing is that Technics is still working - maybe the LEDs have some positive effect on laser diode life
?Blue LED Voodoo
I'm with you Steve.
May I suggest placing two blue LEDs, one in each ear. The effect on the sound is tremendous. It almost seems as if the music is quieter than before and quiet passages are completely silent. I also tried this "double-blind" but kept bumping into my CD player.
I'm with you Steve.
May I suggest placing two blue LEDs, one in each ear. The effect on the sound is tremendous. It almost seems as if the music is quieter than before and quiet passages are completely silent. I also tried this "double-blind" but kept bumping into my CD player.
HI TO EVERYBODY !
I WILL TRY THE LED DISCUSSION ON MY PLAYER !
EVERYBODY SHOULD TRY A GOOD MASTER CLOCK !
BUT MY POINT IS TO RECOMMEND EVERYBODY
TO MAKE SOME KIND OF FLYWHEEL ON THE TOP OF THE PLAYER
(SPINDLE MOTOR) TO LOWER THE JITTER.
MY FIRST TEST WAS OPENIND THE PLAYER & INSERTING
3 CDS ON THE CLAMPER & MEASURING WITH THE SCOPE.
THE SONIC DIFFERENCE IS MORE DEFINITION ON THE ENDS.
(HI & LOW)
ELECTRONICALLY YOU ARE STABILIZING THE PLL SERVO LOOP.
QUESTIONS OR COMMENTS FEEL FREE TO ASK.
I WILL TRY THE LED DISCUSSION ON MY PLAYER !
EVERYBODY SHOULD TRY A GOOD MASTER CLOCK !
BUT MY POINT IS TO RECOMMEND EVERYBODY
TO MAKE SOME KIND OF FLYWHEEL ON THE TOP OF THE PLAYER
(SPINDLE MOTOR) TO LOWER THE JITTER.
MY FIRST TEST WAS OPENIND THE PLAYER & INSERTING
3 CDS ON THE CLAMPER & MEASURING WITH THE SCOPE.
THE SONIC DIFFERENCE IS MORE DEFINITION ON THE ENDS.
(HI & LOW)
ELECTRONICALLY YOU ARE STABILIZING THE PLL SERVO LOOP.
QUESTIONS OR COMMENTS FEEL FREE TO ASK.
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