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Post pics of your builds....
May 26, 2013 at 10:50 PM Post #9,151 of 9,811
Frankenphones...
oQS7a6o.jpg

 
May 29, 2013 at 4:58 PM Post #9,152 of 9,811
I finally put together in a box a lot of pcb I had around. So here is my "good enough, TI ICs only, fully DC-coupled" dac. 
 
Some details:
 
- digital chain: USB-pcm2707-src4192 (with low jitter clock)-pcm1798. Regulation by multiple reg101 ldo.
- I/V stage: opa1632 (with a little twist to get 0v at the DAC outputs) and opa134 to single ended and do the filtering (all fkp caps). Regulation by simple shunt regs at +/-9v.
- output stage: volume control by ds1802 (controlled by a simple momentary up and down switch), opa2134 with the tpa6120a in multiloop. Regulation by lm317/337 at +/-12v.
- headphones protection: upc1237
 
First parts were put together 5 years ago, so it's difficult to get an idea of the whole project's true cost. Probably around 200-250€ (small runs of pcb aren't cheap) but I spent way more experimenting along the way.
 
 

 

 

 
Jun 1, 2013 at 5:06 AM Post #9,153 of 9,811
00940, I love your build, its clean and elegant. respect!
 
I was hoping someone could help me out with something really simple for the next run of my boards. I'm not 100% sure of how i shiou,d be wiring the pot in my cmoy based amp. I'll include an image of how it's routed now. The other way, was with the ground to the middle pins and the signal and source on the outer two.
 

(the plane around the outside is GND)
 
I know this is super simple but I've always had trouble wiring up pots correctly. It'd be super sweet to get this info so I can send of my gerbers and get my next version fabricated. I'll send a board to you if you want it for helping out too :) (it'll be a month or 2 before it gets to you though)
 
 
Peace to all
 
Jun 1, 2013 at 8:16 AM Post #9,154 of 9,811
Quote:
crispchicken said:
00940, I love your build, its clean and elegant. respect!
 
I was hoping someone could help me out with something really simple for the next run of my boards. I'm not 100% sure of how i shiou,d be wiring the pot in my cmoy based amp. I'll include an image of how it's routed now. The other way, was with the ground to the middle pins and the signal and source on the outer two.
 

(the plane around the outside is GND)
 
I know this is super simple but I've always had trouble wiring up pots correctly. It'd be super sweet to get this info so I can send of my gerbers and get my next version fabricated. I'll send a board to you if you want it for helping out too :) (it'll be a month or 2 before it gets to you though)
 
 
Peace to all
Click to expand...


Yes, it's currently wrong, I'm not using the same software but here:
 

 
PS:
it would be a good idea to mark each pin on the input header like:
L in
R in
Gnd
or just like this if you don't have enough space:
L
R
G
 
While we're on the topic of PCBs, I've been working on a 2x 40Wrms speaker / headphone amp for the last couple of days
Here's the power supply board that provides regulated ±32V, ±15V, 12V and 5V from a 25-0-25 transformer:
(yeah, the 3D rendering is crap....)
 

 

 

 
Jun 4, 2013 at 4:39 AM Post #9,156 of 9,811
Here are a few (cellphone-)pictures of my PPA with sigma11 power supply on it's first test-run.
 




 
It sounds absolutely amazing!
The only problem is that I now want a (much) better pair of cans...
atsmile.gif

 
Jun 8, 2013 at 11:36 AM Post #9,160 of 9,811
Just finished my O2. This build was a PITA for me. First I soldered the FETs in wrong position...then my soldering iron broke in two pieces. I didn't use DIP8 sockets as I'm not planning to roll opamps. Pointless because the Designer knows best.

Part are from Farnell, pcb from ebay: http://www.ebay.com/itm/O2-amp-PCB-printed-circuit-board-Objective-2-amplifier-/271219760002
 
Jun 9, 2013 at 3:33 PM Post #9,161 of 9,811
Wonky parts alert!! 
tongue.gif

 
However, I'll bet the o2 is sounding great, even if it was a big pain to build. Mine went together easy but sadly had a few tracks go bad after swapping components too many times... So I'm waiting for a new pcb so I can build it again!
 
Just another note, you might want to try and find a pot that fits in the spot on the board, or failing that, shorten the leads to your current one. Having big loops like that for a signal to go through can't be good for integrity with stray inductance/capacitance etc.
 
Hope you're enjoying it anyhow matey
 
Jun 9, 2013 at 3:43 PM Post #9,162 of 9,811
Indeed I am enjoying it. Thanks for the tip. I've plans for integrating into my DAC, yulong d100 and using a digital potentiometer...
 
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