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Old 6th May 2013, 09:14 PM   #2151
6L6 is offline 6L6  United States
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Quote:
Originally Posted by merlin2069er View Post
Problem is, I don't own a turntable or any records.
That's nothing that an application of proper funding can't fix...
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Old 31st May 2013, 08:04 PM   #2152
Siberia is offline Siberia  Lithuania
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Old 10th June 2013, 11:19 PM   #2153
kop89 is offline kop89  United States
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Would it be a problem if I am using a yellow LED (voltage is around 1.95V)? I have just noticed the build instruction specifies red LED.

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Old 11th June 2013, 03:21 AM   #2154
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Default Red vs Yellow Led

the voltage across the led sets the bias of the stages, so yes it would matter. Not harmful bad, but it changes the bias of your output stage, which he, Wayne, designed to be 1.7v or really close. mine is close to 1.8 and it sounds like heaven, so maybe if you listen then change you could see which you like.
Bias does change the sound in my experience. Hope I helped. enjoy
John
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Old 11th June 2013, 06:43 AM   #2155
omishra is offline omishra  India
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I purchased 10 number of Red LED. All measured voltage drop from 1.65-1.90V. So I choose close match 1.8x range, sounds good. No problem though I can more current P1 for zero output offset.

Last edited by omishra; 11th June 2013 at 06:45 AM.
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Old 11th June 2013, 02:35 PM   #2156
Cobra2 is offline Cobra2  Norway
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Having measured literally thousands of red LED's, I have never found any under 1,8V...
Can anyone please document what type-no that is close to 1,7V?
AND where to get them???

Arne K
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Old 11th June 2013, 06:34 PM   #2157
kop89 is offline kop89  United States
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Originally Posted by Cobra2 View Post
Having measured literally thousands of red LED's, I have never found any under 1,8V...

Arne K
Okay - then maybe there's not much sense to desolder the yellow LED from my board

Can anyone possibly give their wisdom on this matter?

Last edited by kop89; 11th June 2013 at 06:38 PM.
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Old 11th June 2013, 08:09 PM   #2158
Cobra2 is offline Cobra2  Norway
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If the voltage-drop is ok, I do not think you ever will hear the color....

Arne K
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Old 11th June 2013, 08:21 PM   #2159
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Originally Posted by Cobra2 View Post
Having measured literally thousands of red LED's, I have never found any under 1,8V...
Can anyone please document what type-no that is close to 1,7V?
AND where to get them???

Arne K
Filtering for "red" and forward voltage "1.7V" leaves 271 parts in the Digikey category LED Indication-discrete. Quite a few of them are normal axial types and in stock.

BTW I have Panasonic part P605-ND (Digikey) in mine with a forward voltage of 1.8. Never crossed my mind to match them. What happens if the bias is a bit higher? Higher gain? Measured voltage drop is between 1.6 and 1.7V, so I guess I'm OK.

Last edited by Wellerman; 11th June 2013 at 08:28 PM.
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Old 11th June 2013, 08:24 PM   #2160
6L6 is offline 6L6  United States
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You guys are talking about a bias device in a Constant Current Device. If the voltages all around the schematic are good, whatever LED you have is doing a great job!

Stop worrying about it and buy more vinyl -- I found some great stuff today.

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Last edited by 6L6; 11th June 2013 at 08:26 PM.
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