O2 Headphone Amplifier GB

[timpert]

I have ordered/am ordering 750.

I admire you for not bailing out!

 

[ilijatg]

Hy,

i placed the order before the deadend, but don´t appear on the list. Am i in?How much to pay?

g

 

[RocketScientist]

Final PCB Picture

Here's a picture of the final PCB design fully assembled. You can see the extra footprint for the longer shaft volume control and other changes. This board also has pin sockets for the gain resistors.

 

[Alexium]

I wonder if it's possible to drill a 3 mm hole somewhere under the batteries (please don't ask me what for )

 

[RocketScientist]

@alexium, you might drill through some lettering, but there are only a few traces (to the batteries) to worry about. So yeah, you can drill holes no problem. See the top and bottom PCB layouts in the PDF.

 

[NexusPrime]

I just found out about the boards today...Is it possible to buy 4 (US)? How would I do this and who would I contact? I have never done this before and I am new to how Forums work.

 

[Atilla]

I wonder if it's possible to drill a 3 mm hole somewhere under the batteries (please don't ask me what for )

Rubber band?

 

[Alexium]

Rubber band?

Nope, don't even know what you meant
Thanks, RocketScientist. Now that you told me I've finally noticed the layuot PDF

 

[Atilla]

Hahah. I've seen this as a very effective way to hold batteries in place. Rubber band over themm, pass trough the hole, hold with a match or something similar on the other side.

 

[RocketScientist]

@Alexium, you're welcome. And, just so everyone knows, fully suspending the board from rubber bands to isolate it from micro acoustic vibrations, as well as using a $2000 power conditioner for the wall transformer, will greatly improve the sound quality. Users also report orienting the input jacks towards the North Pole during use helps as well...

 

[Alexium]

Will the PCB come factory-drilled? Beacause I have a drill, but I seriously doubt my hands

 

[Atilla]

@Alexium, you're welcome. And, just so everyone knows, fully suspending the board from rubber bands to isolate it from micro acoustic vibrations, as well as using a $2000 power conditioner for the wall transformer, will greatly improve the sound quality. Users also report orienting the input jacks towards the North Pole during use helps as well...

Considering where I live, I guess I need to bury the amp for best effect?

 

[RocketScientist]

Drilled for what? It comes with 233 holes in it. That includes the 3 mounting holes. And for anyone wondering why only 3 mounting holes, that's the required number to determine a plane. A 3 legged stool will never wobble but a 4 legged one will... put another way, camera tripods have only 3 legs for a reason.

 

[Alexium]

fully suspending the board from rubber bands to isolate it from micro acoustic vibrations, as well as using a $2000 power conditioner for the wall transformer, will greatly improve the sound quality. Users also report orienting the input jacks towards the North Pole during use helps as well

Yeah, people hear it all, can you imagine that?.. Oh, and don't forget the steel cone stands!

 

[Atilla]

Drilled for what? It comes with 233 holes in it. That includes the 3 mounting holes. And for anyone wondering why only 3 mounting holes, that's the required number to determine a plane. A 3 legged stool will never wobble but a 4 legged one will...

Hm, tell that to my speakers. They're forming a plane alright. My wooden floor on the other hand... That's something funny and complex that it forms.

 

[Alexium]

It comes with 233 holes in it.

That's exactly what I meant, thanks for clarifying.

Hahah. I've seen this as a very effective way to hold batteries in place. Rubber band over themm, pass trough the hole, hold with a match or something similar on the other side.

Oh, I get it. No, I'm only going to use it at home, so no batteries. I was thinking about combining O2 with a DAC (and a transformer) in a single case.

By the way, what is inside a wall transformer besides the transformer? Or else, what are the requirements for O2's input voltage, aside from >= 12VAC 50/60 Hz? I'm not going to buy a wall transformer but rather put a handmade toroidal trans within the case.

 

[Atilla]

Nothing more there. A transformer. Ideally a fuse of some sort as well. Probably a one-off thermal fuse. That's about it. A nice toroidal will do the job for you, if you're making your own case, no problem.

 

[RocketScientist]

By the way, what is inside a wall transformer besides the transformer? Or else, what are the requirements for O2's input voltage, aside from >= 12VAC 50/60 Hz? I'm not going to buy a wall transformer but rather put a handmade toroidal trans within the case.

A wall transformer is just a transformer (and perhaps a thermal overload cutoff if there's not one built into the transformer itself). A transformer that would work well from Mouser is:

4900-9016RC62

If you want to find a toroidal transformer, it should ideally be 15 - 16 VAC and >= 400 mA. The O2 rarely requires more than 200 mA but it can under some conditions (such as full power sine wave testing into low impedance loads).

 

[coacharnold]

I have a dumb question:

My PCB board is ordered and I have my a good amount of the parts. I can't wait to build this as I'm enjoying the fun of DIY Audio...
I have a nice pair of Sennhieser headphones that sound pretty great hooked up to my rockboxed Sansa's.

aside from being a cool project. Why do I want the O2 amp?

T

 

[clivem]

Payment sent. Thank you.