8 Ch. Summing Mixer (Documents)

[ForthMonkey]

I re-crated Majestic Buzz with DOA.Here is files for self etch.I will share gerbers,too.Now creating PCBs to make my own summing mixer.You can use Majestic Buzz's components values.I forgot to write.

It's for one channel only.You need to build two for stereo.There is a Top side but it's easy to connect with wires.

Circuit
https://dl.dropboxusercontent.com/u/91809016/SUMMER/Untitled.png

Bottom

https://dl.dropboxusercontent.com/u/91809016/SUMMER/Bottom.pdf

Top

https://dl.dropboxusercontent.com/u/91809016/SUMMER/Top.pdf

Layout

https://dl.dropboxusercontent.com/u/91809016/SUMMER/Layout.png

Thanks.

 

[ruffrecords]

I notice there are no power supply decouplign capacitors on the DOAs. Is that deliberate?

Cheers

Ian

 

[ForthMonkey]

I notice there are no power supply decouplign capacitors on the DOAs. Is that deliberate?

Cheers

Ian

I forgot to add decoupling caps but i believe it's easy to add bottom side to DOA's pins.Right?

 

[tmuikku]

lotsa room on the pcb though

also, pin 1 from the inputs go to audio ground? should be better to be able to ground to chassis, maybe a jumper to select where to ground.

 

[ForthMonkey]

lotsa room on the pcb though

also, pin 1 from the inputs go to audio ground? should be better to be able to ground to chassis, maybe a jumper to select where to ground.

I think like you but in orginal design pin 1 goes to signal ground.And i made like this.

 

[ForthMonkey]

BTW can use any other dual op amp instead of OPA 275 in orginal MB?

 

[Andy Peters]

I think like you but in orginal design pin 1 goes to signal ground.And i made like this.

Why continue promulgating a mistake?

 

[ForthMonkey]

Why continue promulgating a mistake?

I don't build like this.Cause if i can solder pin 1 to chassis instead of PCB,i will fix this mistake.Right?

 

[Andy Peters]

I don't build like this.Cause if i can solder pin 1 to chassis instead of PCB,i will fix this mistake.Right?

I'm not clear. Are you connecting Pin 1 directly to the chassis (the right way to do it), or is it going to the signal ground (the wrong way)?

 

[Humner]

I don't build like this.Cause if i can solder pin 1 to chassis instead of PCB,i will fix this mistake.Right?

Because the board terminates with a DB25 connector, your pin1/GND is forced to route to the PCB which means as the PCB designer you are forcing your ground scheme on anyone who uses this board. The best thing to do is terminate the DB25 GND points to a header as most people will want to route this to the chassis GND and gives everyone a choice on where to ground etc. This is the point tmuikku is trying to make.

 

[ruffrecords]

Because the board terminates with a DB25 connector, your pin1/GND is forced to route to the PCB which means as the PCB designer you are forcing your ground scheme on anyone who uses this board. The best thing to do is terminate the DB25 GND points to a header as most people will want to route this to the chassis GND and gives everyone a choice on where to ground etc. This is the point tmuikku is trying to make.

Check out the layout of my DB25 PCB which illustrates this.

Cheers

Ian

 

[ForthMonkey]

I'm not clear. Are you connecting Pin 1 directly to the chassis (the right way to do it), or is it going to the signal ground (the wrong way)?

Normally in this design pin 1 goes to signal ground but i connected it to chassis.I didn't solder db25 conector directly to PCB.So it's easy to connect chassis.

 

[Andy Peters]

Normally in this design pin 1 goes to signal ground but i connected it to chassis.I didn't solder db25 conector directly to PCB.So it's easy to connect chassis.

Understood!