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DIY: Summer Projects

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Silou

Silou

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The power switch looks good, but I really want a flipping switch for the gain control. They are all too small though. No one that is big enough for a 8mm frontpanel.
 

solderdude

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A solution could be to locally mill the rear-side of the front panel thinner so you can fit a regular toggle switch in that recessed part.
 

solderdude

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yes
 
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Silou

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Most of the chassis available have a power socket premounted on the back of the chassis. The O2 uses an AC/AC power supply. How can I make use of the socket? The voltage needs to be reduced from 230V to 15V and the current needs to be limited at 500mA(?). Is a mains filter required? I can only find AC/DC and DC/DC step down converters.
 

solderdude

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I would remove the mains socket. Put a small metal (or plastic) plate in its place and mount a socket for it that matches the one on your power supply.
No filters needed.
The socket you will need is a 2.1 mm barrel socket with a 5.5mm outside diameter.
Buy one that is 'panel mount'.
 
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Silou

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The socket is already in my shopping cart. I just thought it will look a bit nicer with a big socket instead of a little one :D. How will the unbalanced headphone output be wired? Two outgoing wires from every filter to each balanced and unbalanced output? Both negative signals combined to the unbalanced output? Will so many parts and wires have a negative effect on the signal?
 

solderdude

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the + side of the XLR plug right channel to the ring of the TRS
the + side of the XLR plug left channel to the tip of the TRS
the ground of the board which will deliver the + signals to the sleeve of the TRS
 
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Silou

Silou

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the + side of the XLR plug right channel to the ring of the TRS
the + side of the XLR plug left channel to the tip of the TRS
the ground of the board which will deliver the + signals to the sleeve of the TRS
That is so much smarter than my solution :facepalm:
I should think more before I post something :D
I guess the last + is supposed to be a -?
 

solderdude

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Nope the signals come from the board with all the parts on it and that board will supply the + signals (is a normal O2 basically)
So the returnpath also needs to go to the same board.
So the ground of the fully populated board (which delivers the + signals) also needs to handle the return currents (sleeve)
 
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Silou

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I just ordered all the audio connectors. Still waiting to get home to order from Conrad, because I think that I have a 7.50€ coupon at home. Total cost is ~130€ at the moment not including the parts from Conrad and a chassis.
 
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Silou

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Some of the switches/buttons on Ali advertised as DPDT have only 5 Pins. Why is that and can I use them aswell? They are a lot cheaper and look similar to the ones sold by Conrad.
 

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DPDT must have 6 contacts. otherwise they arent dual pole dual throw. Maybe these have a single center contact but that would be really strange.
There could even be 8 contacts when it is illuminated for instance.

Maybe 5 pin are SPDT with illumination ?
 
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Silou

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Yes you are completely right. They are illuminated. I was looking at the two position ones but the three position ones are the correct ones. They are on/off/on instead of on/on, but that should be fine for the gain switch(?).
 

solderdude

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2x on/off is only good for the power, must have 6 pins when illuminated)
2x on/on can be used for both (must have 8 pins when illuminated)
5 pins is SPDT + illumination and can not be used.
 
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Silou

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I have never worked with PCBs and small parts before. Is there any special plummet required? I usually use "Radiolot DIN 8516" which works well for me. It is quite thick though.
 
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Silou

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After 11 hours of driving, I am finally back at home and was greeted by some packages and a flat tire :rolleyes:

is here:
-PCBs
-power supply
-parts to fill the PCB (I think there are also some parts to adjust the gain)
-all audio connectors
-all headphone filters

is missing:
- switch for power ,gain and power supply socket (there are small ones in the parts package though)
-rotary switch for filter selection
-LEDs and fitting resistances
-parts to modify the negative board (which ones?)
-chassis
-??

I will drive to the Conrad store on monday so I can get all the missing parts and finally start the project. :)
 

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Do you plan to use it on batteries as well or only mains fed ?
 
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Silou

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No batteries. Only mains fed.
 

solderdude

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In this case you can populate 1 board and leave out the following parts:
D1, D5 (replace these 2 part with a piece of wire)
D2, D6, R1, R2, S1 and S2 as well as input and output sockets.

Are you planning to mount the volpot on the board or via (short) wires to the board ?
 
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