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Old 27th April 2013, 06:19 PM   #3241
JZatopa is offline JZatopa  United States
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I'm curious, does the O2 circuit need any modification to drive a 47Kohm output or would something with such a high impedance not be an issue.
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Old 28th April 2013, 09:22 AM   #3242
LuisMCP is offline LuisMCP  Spain
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F0016TEK.gif
Quote:
Originally Posted by agdr View Post
Connecting a 10K resistor between
agdr,

It is more a big "click" than a "thump", it has more high freq. content. You can see how much is (9V peak) at image.

I attached a scope capture of G of Q1. pins D and S are also affected, signal is the same without negative part.

Forget to say that recently I build a second O2 and none of these problems was there. It works perfectly without clicks, I believe both are same version (?)

Last edited by LuisMCP; 28th April 2013 at 09:27 AM.
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Old 28th April 2013, 10:51 PM   #3243
agdr is offline agdr  United States
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Quote:
Originally Posted by DJNUBZ View Post
I'm curious, does the O2 circuit need any modification to drive a 47Kohm output or would something with such a high impedance not be an issue.
47k is perfectly OK. You can get up to the full 7Vrms out.
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Old 28th April 2013, 11:02 PM   #3244
agdr is offline agdr  United States
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Quote:
Originally Posted by LuisMCP View Post
It is more a big "click" than a "thump", it has more high freq. content. You can see how much is (9V peak) at image.
Another thing to try is replacing U2, if you haven't already. I know of at least one case where a bad U2 was causing clicks / thumps. You would just temporarily swap the U2 from your working O2 into the other one.
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Old 30th April 2013, 09:55 AM   #3245
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So here's what I did with the B3-080 chassis...built 5 of these.
Soldering all the components onto the PCB was the easy part...the remote mounting, wire cutting/trimming/soldering was the real time killer.

Click the image to open in full size.
Click the image to open in full size.
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Old 2nd May 2013, 04:13 AM   #3246
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02-amplifier, battery-powered at low voltage when the beep, I ask how to deal with, ah, experts know outside the grounds?
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Old 2nd May 2013, 10:34 AM   #3247
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Quote:
Originally Posted by aelfewulf View Post
So here's what I did with the B3-080 chassis...built 5 of these.
Soldering all the components onto the PCB was the easy part...the remote mounting, wire cutting/trimming/soldering was the real time killer.
]
Impressive! Can you upload any pictures of the insides or step by step build guide?
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Old 2nd May 2013, 12:37 PM   #3248
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Problem solving, transistor wrong, you can FQPF10N20C, I used FQPF10N20, check for a long time could not find any problems, thank you!The following are my 02, the switch to change, and this switch is easy to use it.
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Old 2nd May 2013, 04:44 PM   #3249
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Be careful when using a hot air soldering equipment. I was trying to solder the gain switch in place yesterday by using a hot air gun. It worked, but when I flipped the board over I was missing three resistors and two capacitors. They had simply fallen out. Took another hour to put them back in again :S
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Old 2nd May 2013, 06:17 PM   #3250
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Quote:
Originally Posted by availlyrics View Post
Impressive! Can you upload any pictures of the insides or step by step build guide?
Thanks! Glad to oblige

Click the image to open in full size.
The LINE-IN (blue cable) hugs the side of the chassis, away from the power circuitry and output stage. Inside the blue cable housing holds twisted pairs.
Only one battery terminal is mounted, this is necessary to hold the ODAC in place.

Click the image to open in full size.
And here's what it looks like on the other side...
AC power line hugs the side of the chassis, under the power circuitry.
In the middle running almost diagonally is the power switch and DC rails. It's actually recycled from a spare USB cable, which I retain the red/black power line. Even the metal shielding is intact.

Finally there's the gain switch, using a recycled Ethernet Cat5 cable.

So both the AC and DC lines run underneath the board, and are thus separated from the input and output stages by the PCB.

The 2 switches and AC jack is eventually glued to the PCB using silicone adhesive.

(not shown here) the wires leading to the RCA outs have to be soldered onto the ODAC last, after screwing in the RCA jacks to the panel. I find it easier to solder to the surface mount pads meant for the 3.5mm jack.
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