Dual O2 headphone amp in 500 series

[elskardio]

Hi Guys,

I built many variant of the Objective2 Headphone amp in the past year and was always pleased with the results.

This time I went for a 500 series module with 2 independent O2 amps.

The circuit is identical to the original from NwAvGuy, including the power protection. I added a balanced input using a That 1286 IC.

I'm ordering PCBs and panels this week. I might sell the extras if there's enough interest.

Cheers

 

[Whoops]

Looks pretty good,
congrats.

I was not aware of this Objective2 Heaphone amp.
I'm actually looking to build a few DIY headphone amps but there's so many around I was not sure what to build.

Did you built also other DIY headphone amps or just the O2?

 

[elskardio]

I built and tested a lot of different designs. I guess it all comes down to the purpose of the amp...

If you need something simple to blast the drummer's headphones while tracking, the standard CMoy is pretty hard to beat for the price. You probably have every components needed from the leftovers of your previous DIY projects. It can be easily built on a protoboard with any 9V DC wall wart you have lying around

For critical listening, the O2 is to me the clear winner in its price range. But it is not the most musical headphone amp... don't expect any mojo or deep colourful bass here. Its true to the source which I think makes it perfect for studio monitoring.

Cheers

 

[Whoops]

Thanks Elskard,
I would like to build the CMoy for a long time and also an O2,
where did you get PCB's for those projects?

 

[elskardio]

I received my panels this week

 

[imloggedin]

How is the PCB connected to the front plate? Just held by the knobs? I don't see a metal bracket.

 

[Rogy]

Hi Gabriel,

Interesting project!

-Since the API500 format usually handles only 1ch of audio per slot, how has stereo I/O been implemented?

-Are the two Phones jacks carrying the same stereo input signal?

Many thanks,

Best regards,
Rogy

 

[elskardio]

How is the PCB connected to the front plate?

It's hold in place by the potentiometers and the stereo jacks. The PCB is pretty light so its working great. It's not meant to be heavy duty... I wouldn't step on the module

 

[elskardio]

Hi Rogy,

-Since the API500 format usually handles only 1ch of audio per slot, how has stereo I/O been implemented?

Module's XLR input = Left Channel
Module's XLR output = Right Channel

-Are the two Phones jacks carrying the same stereo input signal?

Yes there's only 1 stereo input. But they are 2 independent amps.
Meaning you can have a pair of 32 ohm cans plugged into the first amp, a pair of 300 ohm cans in the second amp and both users have plenty of power + proper volume control.