Schaller - Phaser I (1976)  [schematic]

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rocklander
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Post by rocklander »

apologies if I put this in the wrong place. should it be here or in the 'testing' one?
anyways.. I'm having my first real crack at using eagle. I have the freeware version... she's a beast huh? lots to get my head around.. anywhoo. I had a search for the phasers in general on google and found this lot of schematics, and in there was the schaller phaser I
so I thought I'd try to transfer it into Eagle. I now have two questions.. can someone verify if I got it right?
and will I be able to put it into a board with the free version of Eagle (I'm getting lots of errors pop up about not being allowed to do many things with this version)
thanks in advance.. corrections comments welcome
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schaller phase I.zip
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Post by marshmellow »

Sure you can do a board, that is what's Eagle for. You only got a limitation in size and layers, but you don't have to care about that with this circuit.


Your schematic... there is one major problem. I haven't looked in detail if it's right, I will just give you the obvious mistakes. Every time three or more wires connect in one point, you have to do a JUNCTION (there is also a option so that Eagle will do this in most cases for you). That is the green dot if that should not be clear. Use the DRC and you will get a LOT of errors because of missing junctions. Eagle will point you exactly where they are missing. There are also net wires overlapping pins (for example IC3A).

Second, your opamp power supply won't work this way. You can't just connect something like this just because that's the way you usually see it in schematics if there is no real pin. Use INVOKE and click on each opamp. You have to add the missing power gate and connect the pins the right way to +9V and ground.

Third... the resistor package you chose wastes way too much space. Type CHANGE PACKAGE and click on the resistor, then you will get several options. I would normally go with the 3 holes spacing.

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Post by marshmellow »

Edit button already gone...

I meant to say ERC (= Electrical Rule Check) not DRC, which is the corresponding check for the layout editor.

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rocklander
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Post by rocklander »

great stuff! thanks a heap.. I'll have a go at updating it.
cheers
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Post by modman »

I will move this to the 'buiding' folder until there are verified files. You can repost in the Project folder once you have definite schematics and a layout.
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Bernardduur
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Post by Bernardduur »

Schaller - Phaser.JPG
My unit!

The unit has a double potmeter that functions as the speed of the sweep as a volume control in bypass mode. It overdrives quite quickly with a humbucker guitar......
'No more....... loud music.......'

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Post by electrip »

The Fets are actually BC264 not BC246.

electrip

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Post by Bernardduur »

electrip wrote:The Fets are actually BC264 not BC246.

electrip
True, massive typo!

I've true bypassed the pedal and that works on part of the problems. The volume is now even in bypass mode. I jumpered R1, added a pull down resistor, removed R3 and jumpered R4 and now the overdrive is much less! Still, there is some when I play with an humbucker equipped guitar.

Any thoughts on how to get a more clean phaser like sound? Why is it overdriving my signal?
'No more....... loud music.......'

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