Massdrop Objective 2 Headphone Amplifier (Part 2) Components Upgrade

My previous post about the Massdrop Objective 2 headphone amplifier review is very positive. I had a great result on sound quality aspect especially when combining with the DAC that having the same size of it, is the Massdrop Grace design SDAC.

Both unit still considerably small and can be carry around. Especially since there is 2 batteries slots provided inside of the O2 amplifier casing. So I think it will become a portable amplifier after all if I put the batteries on it.

So here is the progress, including some components upgrade that I think will gives a better sound quality.

I using 2 pieces 9 volt rechargeable batteries from GP, each 200mAh. I just attach them with double side tape on the bottom and put it on each terminal. This O2 amplifier is now become portable and ready for on-the-go.

It is simple as that. The batteries provide enough listening time, about 5 hours until the LED indicator blink means it should recharge with provided wall adaptor from O2 amplifier. Sadly the recharging indicator is not available in this O2 amplifier. In my experience, it require about at least 4 hours recharging time.

After this batteries installation, I want to do another upgrade.

Remember the ugly cables arrangement inside this O2 amplifier? So I will replace them with the better cables. Starting from the signal cable, I will replace using Canare L2B2AT.

Then The next upgrade is replace the wires from PCB to the headphone socket, which is now using non-magnetic copper wire.

The next upgrade is replacing all film capacitor.

Previously this unit using Vishay and I will change to the red Wima capacitor. For me, the Wima capacitor give better sound quality result over the Vishay like this. All new capacitors are the same size with the original and the replacement is just like plug and play.

I also replacing the electrolytic capacitor on the power op-amps is now using the Nichicon Audio KA.

I disable the high gain function by removing R19 and R23 and make a jumper on the gain switch pins as picture bellow. The gain switch right now is always on low setting position no matters you push the switch or not.

In the photo bellow, I wrongly connecting the ground signal cable. I should put it on the smaller lower holes instead on the center like the picture bellow. I change it later and forget to take a photo when it is done. Sorry.

Here is the final result for this components upgrade.

As my expectation, using batteries will give lower noise and quiet background. But the sound quality improvement after those components upgrade are, not so much different after all. 

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