Another Capacitor ID ?

[ReRibbon]

Those little (15uf 40v)capacitors are scattered throughout the channnel. I didn't see any physically connected ti the power rails.

This board is very similar to what was said earlier in regards to the psu being apart from the audio part.

Here is a very crude drawing of the front side of the channel.


The power rails (48v , T Feed?) run through every channel. All channels connected to these rails.  Power is sent through a 1000uf 16 v and 220 uf 63 volt capacitor at the main power connection to the channels. At this point, all channels are linked and live to juice.

 

[ReRibbon]

Same schematic.  Just redrawn.

 

[ReRibbon]

Switch 1 is a 3 position switch for  48/mic'line/T Feed.

The other two switches are just two position on/off buttons. Pretty cool buttons too. They have neon colored things that manually flip to visible when engaged.

Also, on the second sketch, the part that says XFORMER is in reference to the input transformer and not the power transformer.

 

[ReRibbon]

I don't know what bulk supply bypassing is. Please explain?

Imagine a system with a power supply on one board and the rest of the circuitry on another. There is some amount of inductance on the wires connecting the two boards. When the main board needs to pull current from the supply, it has to do so through that inductance, which can hurt transient response.

One solution is a bulk bypass cap on that main board. It is charged by the power supply, and acts as basically a battery. When the circuit needs to pull current from the supply, it pulls it from the cap.

Now, a cap's charge and discharge times are a function of the capacitance, so how fast it can respond to a circuit should be easy to figure out. And this is why you see small (100 nF) bypass caps located at a chip's power-supply pins: the smaller values are faster.

-a

How would this be done?

I do know that some of these caps are in line with some op amp pins. Would this possibly be what you were explaining?

 

[ReRibbon]

Here is a pic of the power supply.

 

[ln76d]

For 100nF bypass you need connect two capacitors on the bottom of your PCB for each opamp.  There's no bypass caps on top of your PCB. One between (+) supply voltage pin -> to ground and another from  (-) supply voltage pin -> to ground. You need to find closest ground connection available.
Am using mostly kemet or avx X7R ceramic axial capacitors and isolation heatshrink on the leads.
Make a little distance between capacitor and PCB tracks.
That's it

 

[ReRibbon]

Ok, I think I understand. I have 4 opamps / channel. Would each one of these opamps need to have this done?



Where are my pictures? Can anyone see them?

 

[ln76d]

You can but mostly it's not necessary. When you changing opamp for high-speed, it's necessary.