Thanks Dave! Will mod my single-ended connection to yours and see if it improves the SQ.
Spent a day to implement the +5v TVDD and replace three 1085 regulators to 7805 for 4399s analog/digital +5V power supply. Added a DIY dual 7805 regulated +5V power supply. One supply to the TVDD and the other supply to the existing LT1085-3.3 regulator (lifted the input pin from PCB).
+5V --> TVDD (cut the original TVDD line as per Nino's photo)
+5V --> supply to 1085-3.3 (lifted 1085 input pin from PCB)
Test 1: Measured TVDD decoupling cap = 5.2V
Test 2: Measured AVDD decoupling cap = 3.3V
Test 3: Measured DVDD decoupling cap = 3.3V
Test 4: Measured DAKV5R/L at 7805 output = 5.03V
Test 5: Measured LR5V at 7805 output = 5.03V
Test 6: Measured LA5V at 7805 output = 5.03V
Connected laptop USB to DAC. Able to lock signal at 44K, but no sound. Measured 4399 output, but no Vdc output (used to be 2.3Vdc before mod).
Any advice to isolate the problem will be much appreciated! Thanks....
+5V --> TVDD (cut the original TVDD line as per Nino's photo)
+5V --> supply to 1085-3.3 (lifted 1085 input pin from PCB)
Test 1: Measured TVDD decoupling cap = 5.2V
Test 2: Measured AVDD decoupling cap = 3.3V
Test 3: Measured DVDD decoupling cap = 3.3V
Test 4: Measured DAKV5R/L at 7805 output = 5.03V
Test 5: Measured LR5V at 7805 output = 5.03V
Test 6: Measured LA5V at 7805 output = 5.03V
Connected laptop USB to DAC. Able to lock signal at 44K, but no sound. Measured 4399 output, but no Vdc output (used to be 2.3Vdc before mod).
Any advice to isolate the problem will be much appreciated! Thanks....
Rewired 1085-3.3 supply pin back to original connection on PCB. Tested again all voltages listed in previous post. All voltage measurement are OK, but still no output from both 4399. Tried toslink signal in from CDP. ak4113 could lock the signal but also no output from 4399.
Wonder if the +/-12V 317/337 regulated power supply only supply to opamp but no other circuit as per schematics?
Wonder if the +/-12V 317/337 regulated power supply only supply to opamp but no other circuit as per schematics?
The regulator used to supply +5v for spdif receiver was already 7805 type. It is not necessary to touch this area if you intent to replace all regulators with 7805 type. If you want to replace it somehow, you should completely remove 7805 from pcb otherwise some problems may occur just like yours.
The AK4113 is supplied by LT1085-3.3, and this LT1085-3.3 is supplied by the 7805. The same 7805 is also supplying 5V to the MCU and LCD which draw higher current. My intention was to supply the LT1085-3.3 with an external 7805 regulated power supply so that the AK4113 could get a cleaner 3.3V.
I have since reverted all the mod to the original circuit but still no output from both AK4399. Not sure how to isolate either the AK4113 or the MCU is bad? Is there any way to measure the AK4113's input and output to determine if it's still good?
Thanks!
I have since reverted all the mod to the original circuit but still no output from both AK4399. Not sure how to isolate either the AK4113 or the MCU is bad? Is there any way to measure the AK4113's input and output to determine if it's still good?
Thanks!
Here's what I discovered when I troubleshoot yesterday:
1. After powering up, MCKO1=1.63V, BICK=1.63V,SDTO=3.3V,LRCK=3.3V
2. Switched through OPT/SPF/USB input selections, no change in the above voltages
3. Once connected either USB or SPF input and switched to the corresponding input selection, the LRCK dropped to 0V
4. Have to disconnect the USB/OPT input turned the DAC off-on to recover the LRCK=3.3V. It sometimes took a few off-on to recover the LRCK voltage. For those failed attempts, the LRCK will rose up to 0.8V then dropped to 0V. For those successful attempts, the LRCK rose to 0.8V, stayed for 0.5~1 sec, then rose to 3.3V.
Based on the above, the USB and OPT inputs should be good (unless both fail at the same time with same symptom). The power supply to AK4113 should be good as well. I suspect either the functionality of the AK4113 is bad, or the MCU is somehow corrupted (not sure if the MCU program can corrupt easily).
Any advice will be much appreciated. Thanks!
1. After powering up, MCKO1=1.63V, BICK=1.63V,SDTO=3.3V,LRCK=3.3V
2. Switched through OPT/SPF/USB input selections, no change in the above voltages
3. Once connected either USB or SPF input and switched to the corresponding input selection, the LRCK dropped to 0V
4. Have to disconnect the USB/OPT input turned the DAC off-on to recover the LRCK=3.3V. It sometimes took a few off-on to recover the LRCK voltage. For those failed attempts, the LRCK will rose up to 0.8V then dropped to 0V. For those successful attempts, the LRCK rose to 0.8V, stayed for 0.5~1 sec, then rose to 3.3V.
Based on the above, the USB and OPT inputs should be good (unless both fail at the same time with same symptom). The power supply to AK4113 should be good as well. I suspect either the functionality of the AK4113 is bad, or the MCU is somehow corrupted (not sure if the MCU program can corrupt easily).
Any advice will be much appreciated. Thanks!
I would rather say both USB and SPDIF inputs fail. Although LRCK is a clock signal with 3.3V peak, measuring with DMM would result in 1.8V mean value (?) when you have a valid audio signal.
By the way, both USB and SPDIF inputs rely on sp/dif. Is your display not affected? Then I would suspect AK4113 (also measure AK4399 supply pins, as terranigma suggested!). I have some spare AK4113 if you want one.
By the way, both USB and SPDIF inputs rely on sp/dif. Is your display not affected? Then I would suspect AK4113 (also measure AK4399 supply pins, as terranigma suggested!). I have some spare AK4113 if you want one.
No problem with the display and all its functions (filters and inputs switching). So long as the SPDIF or USB cable is connected and the filter input is selected correspondingly, the LRCK will drop from 3.3V to 0V. Regardless of whether there's any audio signal being playback.
I have measured the 5V power supply to the AK4399 at the bypass caps as terranigma had suggested. All read 5~5.02V.
I have just ordered 2pcs of AK4113. Thanks a lot for your kind offer and advice. Will report back if it fix the problem.
I have measured the 5V power supply to the AK4399 at the bypass caps as terranigma had suggested. All read 5~5.02V.
I have just ordered 2pcs of AK4113. Thanks a lot for your kind offer and advice. Will report back if it fix the problem.
lomonosoff, which one? complete board with MCU or the one with separate MCU and AKM module?
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