O2 DIY Questions

[Dingus]

I preparing to build my own O2 amp in the next week or so, but I have a couple questions as well as a few things I'd like to clarify.  I like the tone of the responses I see here more than at diyaudio, and the O2 thread there seems to be going off the rails lately.

 

• I want to have rear 3.5 mm input, do I need to be concerned at all about the jack grounding on the chassis?  Only reason I ask is that the JDS Labs guide says that paper washers should be used if placing RCA rear inputs.  I assume this is due to grounding concerns.
• Am I reading the schematic correctly that R1, R2, D2, and D6 as well as the battery terminals can be omitted since I am only going to run this on AC and never on batteries.
• Finally a "can this work". Ultimately, I would like to purchase an ODAC as well, and would like to use the line out on the ODAC to go to my speakers and the line out on the O2 to power my headphones.  Can I make it so that the unit would automatically switch based on the power state of the O2?

Thanks for any help you can give.

[BoredErica]

I preparing to build my own O2 amp in the next week or so, but I have a couple questions as well as a few things I'd like to clarify.  I like the tone of the responses I see here more than at diyaudio, and the O2 thread there seems to be going off the rails lately.

 

• I want to have rear 3.5 mm input, do I need to be concerned at all about the jack grounding on the chassis?  Only reason I ask is that the JDS Labs guide says that paper washers should be used if placing RCA rear inputs.  I assume this is due to grounding concerns.
• Am I reading the schematic correctly that R1, R2, D2, and D6 as well as the battery terminals can be omitted since I am only going to run this on AC and never on batteries.
• Finally a "can this work". Ultimately, I would like to purchase an ODAC as well, and would like to use the line out on the ODAC to go to my speakers and the line out on the O2 to power my headphones.  Can I make it so that the unit would automatically switch based on the power state of the O2?

Thanks for any help you can give.

I am curious. What's wrong with DIYaudio and the O2 thread there?

[KaminKevCrew]

• I want to have rear 3.5 mm input, do I need to be concerned at all about the jack grounding on the chassis?  Only reason I ask is that the JDS Labs guide says that paper washers should be used if placing RCA rear inputs.  I assume this is due to grounding concerns.

The paper washer probably has to do with the length of the solder points on the RCA jacks vs. the headphone jack. Basically, if the ends on the pins stick a ways out of the bottom of the PCB, I would probably put a paper washer down. Also, it doesn't hurt to be safe anyway, right? 

• Am I reading the schematic correctly that R1, R2, D2, and D6 as well as the battery terminals can be omitted since I am only going to run this on AC and never on batteries.

I think you are (don't quote me on that), but why not just put it in anyway? That way if you ever need it on the go, for whatever reason, you won't have to worry about it. 

• Finally a "can this work". Ultimately, I would like to purchase an ODAC as well, and would like to use the line out on the ODAC to go to my speakers and the line out on the O2 to power my headphones.  Can I make it so that the unit would automatically switch based on the power state of the O2?

The easiest way to do that, that I can think of, would just be to get a cheap RCA input selector, and just switch which input to whatever you need. I can't imagine it would be too hard to build something that would do it automatically, but that just sounds like it would be a pain compared to taking the 1/10 of a second to switch it by hand. 

 

Also, +1 to Dark_wizzie as I'm curious about that too. 

[Dingus]

The paper washer probably has to do with the length of the solder points on the RCA jacks vs. the headphone jack. Basically, if the ends on the pins stick a ways out of the bottom of the PCB, I would probably put a paper washer down. Also, it doesn't hurt to be safe anyway, right? 

I think you are (don't quote me on that), but why not just put it in anyway? That way if you ever need it on the go, for whatever reason, you won't have to worry about it. 

The easiest way to do that, that I can think of, would just be to get a cheap RCA input selector, and just switch which input to whatever you need. I can't imagine it would be too hard to build something that would do it automatically, but that just sounds like it would be a pain compared to taking the 1/10 of a second to switch it by hand. 

 

Also, +1 to Dark_wizzie as I'm curious about that too. 

Nothing is wrong per se with audiodiy, I am just more familiar with the community here.

 

I think maybe we aren't communicating well about the 3.5 mm or RCA issue.  These would be connected off the board and go through a hole in the back of the case, so no issue with the pins extending below the pcb and shorting on the case. From what I'm reading in your post you are talking about through hole parts, and I am talking about chassis mount.

 

As far as needing it on the go, unlikely in the next many years.  I have a young child (hopefully one more before we're done) and travelling with them while wearing headphones is right out. I don't want to be that dad that doesn't notice their child kicking the seat in front of them because they're too busy rocking out on their headphones.  I've sat in front of their child.

[Fluffinator]

As far as needing it on the go, unlikely in the next many years.  I have a young child (hopefully one more before we're done) and travelling with them while wearing headphones is right out. I don't want to be that dad that doesn't notice their child kicking the seat in front of them because they're too busy rocking out on their headphones.  I've sat in front of their child.

You're a good father..

[Dingus]

Just a few components left to solder in, and then I need to make my front and back plates. I found this old thread and love what this LTT member did, but he's been inactive for over a year.  Any idea where I can find the front panel plans with 1/4" headphone jack.  Even just an idea of how much I would need to adjust the Y value from NWAVGUY's posted plate.