Originally Posted by w357
All that is circled with colored frames:
1. red - shunts power DACs and operational amplifiers.
2. blue - the amplifier low-pass filter and amplifier for headphones.
3. Green - capacitors of low-pass filter
4. Orange - kit of headphone amplifier (two resistors and two capacitors in pairs for each channel)
5. Purple - 5V voltage regulators for DAC and LPF (of 3 stub - one in the same place, but on the back of side of the board)
6. Pink - 3V voltage regulators of headphone amplifier
7. Yellow - power inverters of operational amplifiers
Nothing else to touch it, unless Y want to become a non-working player!
stabilizers, inverters, and operational amplifiers unsolder it's best flat-tip type "cutter" or "paddle". It allows you to warm up once all the legs on one side of the chip and lift it.
low-pass filter replacement stabilizer placed on the reverse side of the board will have to unscrew the two screws and remove the motherboard from the case. in this case you should try to not bend it to cracked lead-free soldering processor! better once bend the edge of the case.
after removal of the components should be removed excess solder .
Look above and change in strict compliance:
1. change it for quality ceramic NP0 0,1 uF. I set the capacitors of the firm Murata. here it should be noted that shunts are a pair of DACs capacities of 10uF and 0,1 uF. Unsolder it all and put in place Murat 10uF (space for smaller capacity are empty).This replacement will clear some power DACs and the opers of noise.
2. still skip this point ...
3. Change at the highest quality film capacitors, which will be found. I put WIMA FKS2. Ideally would put sulfide Panasonic, but only if it is available soldering hair-dryer, infrared station, or a stove. Soldering iron sulfide capacity would be killed instantly. This is replacement capacitors once and for all fix the problem Player’s bright sound.
4. just unsolder and forget. No replacement necessary ...
5. change in LP2985AIM5-5.0
6. change in LP2985AIM5-3.0
7. change to TPS60403.
Now we choose the op-amp for low pass
that is, return to step 2, missed earlier ...
here we have some leeway to set the desired character of the future sound mod.
from what I've tried it myself, I offer the following options:
LM6172 - dynamic sound, quite smooth, melodious. slightly rounded attack (because of the smoothed small parts), good depth, punch in midbase.
LM4562 - on analyticity and the level of distortion is comparable to the previous version, but has a slightly more melodic sound. cleanest RF, isolated middle and dry, but tight bass. the overall sound is extremely detailed, accurate midrange-oriented, fast. I myself stopped on this amplifier.
[review of amps translated partly]
WARNING! installing low-pass filter amplifier to its outputs (1 and 2 in the photo) to the level above the board! they should not be soldered to the board (in air)! In this case, the line out audio player goes straight to the DAC on the negative feedback loops of op-amp low-pass filter. Of course don’t uselow impedance load to LO if you do not want to kill inadvertently DACs.
After all these steps, wash board using CRAMOLIN FLUX-OFF (can be in two or three times with a toothbrush, for better removal of flux), giving dry.
currently there are several options Amplifier:
1. well-known "Storb modes" based on the AD8397. it will not consider
2. Storb analogue-mode PCB authorship Symmcat