Build Your Own Clone Message Board

How would I go about making a buffer pedal, but with 4 outs rather than 1? I have a circuit for the buffer, but it just has 1 output. So how do I get to 4?

Hi,

Check out the buffer in the Layout Vault.

http://www.buildyourownclone.com/board/viewtopic.php?f=41&t=18466

The layout i did outputs two from one input. You could use a quad opamp and duplicate the parts to use all-four sections.

Let me know if you have any questions.

Cheers,
Ian

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Its probably just because I'm pretty new to all this, but I don't really get what you're saying. Could you explain more clearly?

Yeah no worries.

AS I UNDERSTAND IT (take the following with a pinch of salt!)

The buffer essentially consists of a simple input and then a repeatable route through the opamp.

Once the input section is complete (the input cap and the biasing) the opamp section consists of the inverting input and output tied together with the signal coming in on the non-inverting input. The opamp section can be used in a single opamp, a dual or a quad...etc.

So by applying the input signal (after the input cap and biasing) to the repeated opamp element it can be used to generate multiple outputs from a single input.

Do you build on stripboard? Give us a couple of minutes and I'll draw up a quick layout.

Cheers,
Ian

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Righty,

Here we are, obviously it is not verified but it looks right to me.

If anyone wants to look over it to verify my thoughts - cool.



Hope it helps.

Cheers,
Ian

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Ok, I get it now. But what is the resistor value 2M2?

That's a 2.2 Megaohm resistor 2M2 is a commonly used abbreviation rather than 2.2M because it's easy to lose a decimal place.

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Could I just use any quad op amp, or does it have to be a TL074?

That is a good question!

I originally used the TL072 (dual splitter) as it has JFET inputs for each stage, and the associated impedance. I think a TL084 is also JFET so that should work OK.

What Quad were you thinking of?

Cheers,
Ian

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I just think my grandpa has some laying around and I was going to try and use some of those. So if it has JFET I can use it? Is there any way I can tell it has JFET, or do I just need to look them up?

Hi,

I'd probably just give it a go! I used JFETs as the idea was combining an IC buffer with a JFET splitter. It should be pretty obvious from the datasheet if it is a JFET opamp, if in doubt just ask and i'm sure you'll get help.

Cheers,
Ian

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