If anyone has success in modifying the AA-AP23123 to facilitate increasing the supply voltage to the line drivers and PT2259 volume control, please post some detail.
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New Wondom ADAU1701 DSP Unit
- Thread starter Weeb Labs
- Start date
I did a little more digging around mine today. It looks like it can be fairly easily done.
There are 3 voltage regulators marked "S55ND" labeled U203, U205 and U206. There is an unpopulated pad for a fourth one labeled U204. With 5v in I measured 3.18v for U203, 2.82v for U205 and 2.72v for U206. The 3.18v appears to be the analog supply,the 2.82v the digital supply and the 2.72v supply is used for the GPIO controls, to keep them below the digital supply.
EDIT: I probed around some more including the ADAU1701, pins 36 and 48 (AVDD) are at 2.72v, pins 13 and 24 (DVDD) are at 1.75v and pin 18 (IOVDD) is at 2.72v.
It appears that you could cut the trace above the "4" in "ADSP-D2.4" (red line) and then run a jumper from D103/C221/C222 (I measured 5v there) to C313/C334 (pink line, probably want to route it better). The only issue I see is POT4, the volume control for the 12F1822 PIC, it uses the 3.18v supply, the other pots and the 2 toggle switches use the 2.73v supply.
EDIT: It seems possible you could bypass U203 and not have to cut anything. It begs the question why they went through so much trouble to regulate the voltage down in the first place? I'm getting 0.13v drop across each of the inductors, so you could get ~4.74v if you remove U203 and jumper across it. This way POT4 would also be at ~4.74v and you would get additional LC filtering that you don't get at the raw 5.0v at C221/C222. But no voltage regulation other than what your external supply offers.
Also interesting is I'm measuring 2.0v at J106 pin 1 and J103 pin 2, both labeled +5V. Also measured 2.72v at J104 pin 20 labeled +3.3V. I did get 4.9v at J105 pin 5 labeled +5V.
There are 3 voltage regulators marked "S55ND" labeled U203, U205 and U206. There is an unpopulated pad for a fourth one labeled U204. With 5v in I measured 3.18v for U203, 2.82v for U205 and 2.72v for U206. The 3.18v appears to be the analog supply,
EDIT: I probed around some more including the ADAU1701, pins 36 and 48 (AVDD) are at 2.72v, pins 13 and 24 (DVDD) are at 1.75v and pin 18 (IOVDD) is at 2.72v.
It appears that you could cut the trace above the "4" in "ADSP-D2.4" (red line) and then run a jumper from D103/C221/C222 (I measured 5v there) to C313/C334 (pink line, probably want to route it better). The only issue I see is POT4, the volume control for the 12F1822 PIC, it uses the 3.18v supply, the other pots and the 2 toggle switches use the 2.73v supply.
EDIT: It seems possible you could bypass U203 and not have to cut anything. It begs the question why they went through so much trouble to regulate the voltage down in the first place? I'm getting 0.13v drop across each of the inductors, so you could get ~4.74v if you remove U203 and jumper across it. This way POT4 would also be at ~4.74v and you would get additional LC filtering that you don't get at the raw 5.0v at C221/C222. But no voltage regulation other than what your external supply offers.
Also interesting is I'm measuring 2.0v at J106 pin 1 and J103 pin 2, both labeled +5V. Also measured 2.72v at J104 pin 20 labeled +3.3V. I did get 4.9v at J105 pin 5 labeled +5V.
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Bypassing the voltage regulator is by far the easiest route to take. A jumper across connecting the two inductors (after removal of U203) does supply 5V to the analog output stage. Clipping still occurs around the final output line drivers. Is it possible there are diodes connected across the audio output lines? Those 3 legged devices might be diodes, or are they transistors?? With the 5 v modification the audio output is much higher on the stage prior to the output liner driver. I may opt to rewire the RCA output jacks accordingly (possibly with a series capacitor to preclude DC on the jack).
I'm thinking of adding this headphone amplifiers that could work as preamplifiers after the analog output of the AA-AP23123. Might not be the cleanest solution but works for increasing the output voltage
On my unit the front panel switches are labeled as GPIO 0 and GPOI 6. and the led's are labeled as "Power" and "Busy". What exactly is busy??A common problem with low cost Chinese imports is bizarre wording caused by the writer's poor English language skills.
I think this would be a good use for the Busy / Signal LED. It could be set as a Clipping light. https://ez.analog.com/dsp/sigmadsp/f/q-a/64667/limiter-indicator-led
New Wondom ADAU1701 DSP Unit
Would it be reasonable to mess with something like this instead of Camilla DSP from the point of view of someone who doesn't mind screwing around with software, but doesn't know electronics? https://www.aliexpress.us/item/3256805766033082.html
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Have you tried it yet? I tested voltages and found only 2v on both J106 in 1 and J103 pin 2, 4.6 0 on J105 5v pin and 2.76 on j104 pin 20. That is suposed to be 3.3.v, so the 3.3v is higher than 5 volt! I even ran audio through it to make sure it didn't have some sort of sleep mode. I need 5v for an aditional DAC . Any idea where I might get it?I dont want to go all the way across the board to J6, Also, I'm not the best solderer, and those pins are tight together.
Have you checked voltage on the volune control chip? It requires a minimum of 4v. If that is also low it could contribute to the issue.
New Wondom ADAU1701 DSP Unit
I added the PCM5102 boards to an ADAU1401 evaluation module, not the AA-AP23123. You'll lose some of the front panel controls on the AA-AP23123 if you add DACs, see post #30 above. I think a better solution to get more voltage out of the AA-AP23123 is to increase the voltage to the SGMICRO...
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