I've just finished servicing my newly aquired DD-10, and this beast is now loud! It is not an issue with a faulty knob as I can crank-up the volume up to insane levels... The DD is paired with a MDR 7506, which is NOT a low impedance headset. My other sony (gx612) is loud, but not on such a magnitude. Any idea on how to tame the beast? I'd rather avoid a jack reducer, and would prefer to implement what Sony was doing for the French market (which they had to tame down, I can now understand why!).
As a side note, I've got to say, this unit is a joy to fix. One can see how Sony cut corners with this cheaper DD (the internals do include more plastics, no line-out output), but this is overall a more robust design: the hinge is much more sturdy, one can remove the PCB without the need to de-solder the motor wires, the infamous gear has been replaced by a more common belt and pulley mechanism, all this while retaining the disc drive for the capstan. Dolby B is also included. Last but not least, even if I bought a complete refurbishing kit including capacitors (fixyouraudio), the CMS capacitors are still strong. All in all that's a unit that is very easy to service, not overly expensive (for a DD...), and sounds very good. Hence the reason I'd like to address the high volume,
There are 2 main ways to fix your problem: increase the series resistors at the output (this will change the frequency response) or to linearize the volume potentiometer. Second is prefferable since I assume your main problem is you are only using 30-40% of the range volume potentiometer has. For doing that you can add a resistor in series with potentiometer wiper (10K).
The pot is actually 2 pots in one. There are 2 10k resistors prior to the knob, so that's what I was considering modifying assuming an additional 5k~10k would make it do. This being said, there are two smal caps between these resistors and the knob. Under this circumstance, does it still make sense to raise the resistance of these 2 resistors? (Resustor highlighted in blue, the knob is the component with 5 rectangular tabs) Well this what my analysis came to, ...until I removed the shiny new Duracell Ultra installed while servicing the dd10. I installed some duracell (not fully charged) nimh battery and all of a sudden the volume went back to acceptable levels. I have to say that relying on a weaker power source seems a far less troublesome approach than messing with the PCB...
You need to put the resistor in series with the cursor rather than increase the value of R108/R208 to 20k. As for the alkaline vs NiMH, volume shouldn't vary that dramatically between 1.5V and 1.2V/cell.
