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DAC-END R (ES9018) full assembled board

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#1,461
audiodesign said:
1) It is necessary reduce the current on shunt changing R4 and R5 from 10 ohm to 15 ohm because now the temperature of the second smd transistor is very high. Quanghao can send you the 4 x 15ohm smd resistors to make this simple correction.

2) Eliminate also R9 and R10 in the +15V and -15V shunt.

3) Add a 47uF or 100uF capacitor in parallel to the original 47uF on the 1.2V analog (L & R) near the jump to eliminate the little oscillation.
Click to expand...
Hi Andrea,
I am wating for my dac. Do I need to ask these modifications from Quanghao or this will be the actual version ?
 
#1,463
audiodesign said:
1) It is necessary reduce the current on shunt changing R4 and R5 from 10 ohm to 15 ohm because now the temperature of the second smd transistor is very high. Quanghao can send you the 4 x 15ohm smd resistors to make this simple correction.

2) Eliminate also R9 and R10 in the +15V and -15V shunt.

3) Add a 47uF or 100uF capacitor in parallel to the original 47uF on the 1.2V analog (L & R) near the jump to eliminate the little oscillation.
Click to expand...

Since I have my DAC, I have a different question.

Are we going to get a "kit" of the parts required to rework the DAC?

Can you circle the affected parts on a picture of the DAC?
I am not using the opamp board, so I think I have fewer parts to replace.

For item 3), can you show a picture of a reworked board?

Thanks
Randy
 
#1,464
DAC module - correction

Add a 47uF or 100uF capacitor in parallel to the original 47uF on the 1.2V analog (L & R) to eliminate the little oscillation at 14KHz.
 

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#1,466
Let clear the points: we have to change R4/R5 to 10 ohms for preventing shunts to melt, add 47µF to stop an oscillation and change the firmware. For a finished product...
Can you precise how to connect the PIC programmer on the display board (what connector) as I found the views for the hardware mods? What is the PIC reference?
A friend of mine has a PIC programmer and the know how to use it so this part will be the easier for me.
I think it will be find to receive the new components (ie 4 10 ohms smd and 2 47µF Oscon).
 
#1,469
Firmware upgrade with Pickit2

Move both the 2 jumps in the second position.

You can do this operation with the DAC switched on.

After flash disconnect the Pickit 2 and move the jumps in the original position.
 

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#1,470
Op-amp module corrections

1) It is necessary reduce the current on shunt changing R4 and R5 from 10 ohm to 15 ohm because now the temperature of the second smd transistor is very high. Quanghao can send you the 4 x 15ohm smd resistors to make this simple correction.

2) Eliminate also R9 and R10 in the +15V and -15V shunt.
 

Attachments

  • Remove_R9_R10_and_replace_R4_R5_with_15ohm.jpg
    Remove_R9_R10_and_replace_R4_R5_with_15ohm.jpg
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#1,472
audiodesign said:
1) It is necessary reduce the current on shunt changing R4 and R5 from 10 ohm to 15 ohm because now the temperature of the second smd transistor is very high. Quanghao can send you the 4 x 15ohm smd resistors to make this simple correction.

2) Eliminate also R9 and R10 in the +15V and -15V shunt.

3) Add a 47uF or 100uF capacitor in parallel to the original 47uF on the 1.2V analog (L & R) near the jump to eliminate the little oscillation.
Click to expand...

Quanghao, is it possible to apply above correction before send the dac to me. I'm afraid of sms. Thank you
 
#1,476
115V?

I received my DAC two weeks ago, but only now had the time to give it a look.
The power cord has a US plug and the transformer (model R-30, 25VA) say 115V.....
Before plugging the DAC in at 220V I guess I'd better ask if this is fine or if some mixup has occurred😕
 
#1,480
Hi Palmito,
I have the LL1684 hooked up like in this schematic.
Attention: the pin layout is from the bottom view (where you can see the pins), not like in the LL1684 pdf where it is the component view (where you see the label).
Regards,
Danny
 

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