How to provide + and - to an opamp

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Meanwhile in another rabbit hole

I began to wonder if the diode network in the crate schematic was equivalent to the oft seen traditional "diamond" shaped bridge rectifier

Ok so time to draw each side by side and make a comparison

My conclusion is that yes they are the same

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So I wonder why Crate drew it like that

But I am very glad that they did draw it like that because it was easier for me to make heads or tails out of it 

[Loudthud]

So I wonder why Crate drew it like that

Most schematic programs won't allow you to rotate a symbol by 45 degrees. You can only rotate things in 90 degree increments. If you are using discrete diodes, you are usually stuck with things going left, right, up or down, unless someone created a diode symbol with the diode going diagonally. Most engineers are too lazy or don't know how to create special symbols.

If you have a symbol for a bridge rectifier, it can be drawn with diagonal diodes. But it's a complete symbol, not individual diodes. If you want individual diodes, you have to use the symbol for individual diodes or when PCBs come back, there will be the footprint for a bridge rectifier.

[Kaz Kylheku]

Most schematic programs won't allow you to rotate a symbol by 45 degrees.

Even so, if you prefer the diamond configuration, you can approximate it like this:

[Kaz Kylheku]

Actually, the above way of drawing it is clearer than the diamond. It's obvious that the diodes are in a school, all swimming in the same direction. This is not as immediately apparent in the diamond; the 45 degree slants have a cognitive disadvantage.

Yet, a cognitive advantage of the diamond is retained and perhaps enhanced. We see at a glance that there are two "swim lanes" of diodes in parallel, but in the same direction, so the output circuit goes one way (obviously it is rectified). Then we just have to understand how the driving circuit injects current into it.

Three-phase rectifiers are pretty much drawn this way. If you search for "three phase rectifier schematic", you won't find any attempt do anything diamond-like, though many of the diagrams show the motor winding coils in a kind of triangle.

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Thanks guys you all are the best for real 

Going back yet again to the crate schematic I was interested to see the grounding scheme on the primary side

It looks like they have the neutral side grounded to earth 🌎 and chassis...but why the capacitor

Specifically C26 ?

Might be time to give you guys a break and read up on mains wiring to an amplifier 

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Btw I just spent about thirty minutes looking through my books for those crazy "is this circuit the same as this one" problems

Like they would have a circuit that looked like a jungle gym and then something much simpler to compare it with 

[Kaz Kylheku]

It looks like they have the neutral side grounded to earth 🌎 and chassis...but why the capacitor

Specifically C26 ?

Is this about the Crate GX-15? I see that this has an 11:1 voltage divider (R38 R39) feeding off the speaker output line to create a lower voltage output for the line out jack. C26 is in parallel with the lower leg of this, and indeed grounded, to roll off the high end. Are we looking at the same thing?

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Whoops sorry this is the one I'm looking at the capacitor is by the three prong power cord

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[Kaz Kylheku]

'm looking at the capacitor is by the three prong power cord

OK, that's a much older schematic than what I was looking at (which doesn't have it).

That is a capacitor for suppressing noise and spikes. A special capacitor has to be used for this. In the neutral-to-ground position, a "Class Y" capacitor is required, which fails open.  A placement between hot and neutral calls for "Class X" which fails short, blowing the fuse or tripping a breaker. Class X and Y capacitors also have very high voltage ratings compared to ordinary ones we use in circuits.