[3amsleep]

here´s my pcb for my cmoy AD8066 amp. any suggestions before i manufacture it??

*----
updated my pcb/schematics to reflect the suggestions made. i also added a simple wallpower/nimh charger section.
*---

updated my PCB again.

added pinouts for an Alps 10K pot, redid the traces to let the ground plate flow everywere but near the AD8066 to prevent oscilation, and lowered the gain to 6.

*input caps are optional, i´ll jumper them if i dont need them.

the schematic says 0.1uF for bypass caps, but i´ll try 0.01uf first.

 

[TzeYang]

Is there any reason to use high resistance for your input series resistor?

They do increase some noise. Also, you don't really need the input caps.

 

[3amsleep]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif Is there any reason to use high resistance for your input series resistor? They do increase some noise. Also, you don't really need the input caps.

that 100R and 100k are just arbitrary, i think i will use something like 10k or lower on R2 and R3. also i´ll have to tune the ouput resistors when i test the amp. cause i have no idea how it will behave.

i was thinking about lowering the gain on the amp, but im not sure if it´ll benefit from that on a "no-pot" config.

mmhmm... why i wouldn´t need the input caps?

 

[FallenAngel]

1) An input resistor that large will seriously attenuate the signal, no need to have it above a few K Ohms.

2) You don't need input caps unless your source has DC.

 

[3amsleep]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif 1) An input resistor that large will seriously attenuate the signal, no need to have it above a few K Ohms. 2) You don't need input caps unless your source has DC.

lets check for dc......cool my audio card is outputing only 0.08mv dc... is that clean enough¿?

* im thinking about getting a iaudio7.. i guess DAP dont ouput dc right?

 

[FallenAngel]

Quote:

Originally Posted by 3amsleep /img/forum/go_quote.gif lets check for dc......cool my audio card is outputing only 0.08mv dc... is that clean enough¿? * im thinking about getting a iaudio7.. i guess DAP dont ouput dc right?

Should be all good.

 

[3amsleep]

updated my pcb/schematics to reflect the suggestions made. i also added a simple wallpower/nimh charger section.

*input caps are optional, and i will jumper them if i dont need them.

im still wondering if there would be any improvement if i lower the gain to, maybe, 8 or 6 ?.

 

[Pars]

If you are going too have these made by a board house, is there some reason you didn't use a ground plane on the top layer? It appears that you poured one on the bottom layer, but it got so chopped up by traces that its effectiveness is limited. Provisions for an Alps RK097 pot with switch would also be nice.

 

[TzeYang]

It's a single layer board.

I believe he did this to save cost.

 

[3amsleep]

Quote:

Originally Posted by Pars /img/forum/go_quote.gif If you are going too have these made by a board house, is there some reason you didn't use a ground plane on the top layer? It appears that you poured one on the bottom layer, but it got so chopped up by traces that its effectiveness is limited. Provisions for an Alps RK097 pot with switch would also be nice.

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif It's a single layer board. I believe he did this to save cost.

yeah i need to save costs.

i will have it manufactured by a friend that works on a board house. He manufactures single boards and small quantities so that is good for me since i want to test the amp before i make more PCB.

im trying to get the ground plane in between that section with the power traces, but im keeping it far from the AD8066 on purpose.

i´ll try to add a pot, its not my priority, but ill try.

 

[NelsonVandal]

Everything's a matter of taste, but a volume pot is very handy. I would trade 18V for 9V to get a volume pot and a buffered ground for the return currents from the headphones like in Mini3 for instance. TLE2426 isn't known to sound good in this position, but it has a very low output impedance, and AD8066 is one of the better monolithic opamps, so you'll still have a fast "punchy" amp with very good imaging, I think.

 

[3amsleep]

updated my PCB again.

added pinouts for an Alps 10K pot, redid the traces to let the ground plate flow everywere but near the AD8066 to prevent oscilation, and lowered the gain to 6.

*input caps are optional, i´ll jumper them if i dont need them.

any suggestions before i get the pcb made?