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Old 12th November 2012, 08:32 PM   #301
oz7aff is offline oz7aff  Denmark
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Have a look here:
Click the image to open in full size.

If the meter shows 140 mV, then the current through the capacitors is 14 nano Ampere, that's 0.000000014 Ampere, it is simply the leakage current you are measuring.
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Old 12th November 2012, 08:36 PM   #302
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Thanks Max

I would like change the ceramics capacitors of the input and something else, nothing complicated.

What do you think?

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Old 12th November 2012, 08:40 PM   #303
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Quote:
Originally Posted by oz7aff View Post
Have a look here:
Click the image to open in full size.

If the meter shows 140 mV, then the current through the capacitors is 14 nano Ampere, that's 0.000000014 Ampere, it is simply the leakage current you are measuring.
Ok Thanks...

I didnīt know this
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Old 12th November 2012, 09:14 PM   #304
oz7aff is offline oz7aff  Denmark
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Quote:
Originally Posted by blackdod View Post
I would like change the ceramics capacitors of the input and something else, nothing complicated.
Normaly there will by no problem in changing the type of capacitors.

Is there a way I could see the schematic ?
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Old 12th November 2012, 09:35 PM   #305
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Yes, I have the schematic and I can see that the input capacitor is marked with the number of 1U on my board (value 1 uF on the schematic ŋ?), just after the volume pot.

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Old 12th November 2012, 09:40 PM   #306
oz7aff is offline oz7aff  Denmark
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But I have no schematic to look at, is there any place I can see it ?
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Old 13th November 2012, 11:47 AM   #307
mkusan is offline mkusan  Croatia
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Quote:
Originally Posted by oz7aff View Post
But I have no schematic to look at, is there any place I can see it ?
I believe you can, here it is thanks to Miles Campbell.
Attached Files
File Type: pdf JHL Headphone Amp MKI Schematic.pdf (48.5 KB, 136 views)
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Old 13th November 2012, 02:07 PM   #308
oz7aff is offline oz7aff  Denmark
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Ok, I see that the schematic is the same as used in the blue PCB. There is an error on it C23 and C24 shall have + to GND. And why use a capacitor on the output ?
Replacing the input capacitors with some 1 uF plastic type like Wima should be OK.
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Old 13th November 2012, 05:15 PM   #309
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Quote:
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I believe you can, here it is thanks to Miles Campbell.
Hi guys

Ok, itīs the schematic. Thanks Mkusan.

Well, I used a cap on the output because I measured the voltage between the Output pad and signal ground and the volt was around 500 mVolt.

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Old 13th November 2012, 08:42 PM   #310
oz7aff is offline oz7aff  Denmark
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Quote:
Originally Posted by blackdod View Post
Well, I used a cap on the output because I measured the voltage between the Output pad and signal ground and the volt was around 500 mVolt.
It should be possible to reduce the offset there by means of VR3/4
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