Help with some stuff I designed?

[Silver Blues]

Would it be too much to ask for one of you to do some layouts for some of my own circuits so I can prototype them and then let the Tagboard community have at them?  I'm not too good with making vero layouts, even though it is my favorite building medium.

--Silvie

I'll post the schems later.

[IvIark]

Post them up and we'll have a look.  I can't guarantee when they are likely to be done because we both have quite a large to do list, but we'll see

[Silver Blues]

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[Geiri]

I'm still practicing making layouts and they're all fairly small at the moment. If you have anything slightly smaller I'll have a go at it

[Silver Blues]

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[GoranP]

I always use this one from Beavis for an order switch. Just omit the fourth (or don't, if you really need the led ) pole.

[Ross]

Nice to see more people doing bass designs! The Poinsettia looks like a fantastic circuit. I really like the idea of a MOSFET gain stage slamming that low-ish gain op amp section. If you get oscillation at high gain settings, you may want to put a very low value cap (33pf should do the trick nicely) between pins 1 and 8 of the CA3130, as it is externally compensated. You also may want to put a filter cap on the V+ rail, but it may not be necessary.

[Silver Blues]

Thank you  and thanks for the tips, I hadn't thought of that compensation thing.

--Silvie

[Geiri]

Tell you what, that black box has two circuits, one before the switcher and another after it. I'll do them separately and you can add the switcher on your own. How's that? I've got free time tonight so I'll probably have something for you to look at soon.

[Geiri]

Please please please, have a close look at the layout side by side with the schem. This is the left side of the schematic, before the order switcher. I'm still getting a hang of doing layouts so there might be something wrong with it. Also note that Grit 1&2 is pure guess. It's either 1&2 or 2&3 You'll have to let me know if the pots are reversed.



Hope it's right and that it works!

[Geiri]

Same precaution info as in the post above. Check this because I'm quite tired and there could be mistakes. I'll correct them if they get posted here.

So here's the other side of the schematic. Once both have been tested and perfeced, I bet it would be easy to make a neater layout with both circuits on one veroboard.

[Silver Blues]

Oh man, I can't begin to tell you how happy I am. It's damn late right now but I'll look closely at it tomorrow.

--Silvie

[Silver Blues]

Okay, layouts checked. Circuit B looks spot on, circuit A is laid out properly except D1 and the 220u are reversed, and I think I intended Grit to be 1 and 2+3. You are getting the hang of this, Geiri

--Silvie

Now, let's see when I have time to build... I still have an Engineer's Thumb to finish and no more hardware...

[Geiri]

Ah yes it's because of the -9V so I need to think that ground isn't really ground. Weird stuff hah!

Thanks mate and I hope this will be useful for you. I'd be happy to try a combined layout once you've perfected your circuit. I'd love to hear how it sounds!

Here's an updated layout and it should be right

[Jederino]

I'm practicing doing layouts, and thought I'd give Poinsettia a shot.  Reading through the layout guide, Vref went to the trace that leads to pin 3 of the IC.  I now realize that can't be done on this scheme.  I guess I don't have my head around Vref.  What I understand is Vref to 4.5v, V+ to 9v . . . just don't know where 4.5v is.

A bit more of a schematic to chew when it's one of my first, but I like the challenge.  Your help would be much appreciated!

I love the idea of these schemes though.  Bassist myself, once I get one that looks good, I'll add the parts to my pending Tayda order.

[Silver Blues]

That little network at  the bottom is the op-amp's bias network. The middle trace (the one connected to the positive of the capacitor) is where Vref is. The two 10K resistors are a voltage divider, which creates 9v at the top and 4.5 in the middle. Just connect the input of the op-amp through the bias resistor to Vref, i.e. from the 1M at pin 3 to the middle of the divider. (I hope I explained that correctly.)

Also, as none of these schems are verified yet as far as proper (and nice-sounding) functionality, I'd ask that you not try to build them yet, until I can be sure of their integrity. I'll let you know when  Hopefully Mark or Miro can post them on the main page when they're ready and then you can go to town with them. Is that okay with you?

--Silvie

[Jederino]

Makes perfect sense, thanks Silvie.  And, yes, I'll definitely wait until its verified to invest in parts.  Wish I had the backstock of components, so I could breadboard it and work on it, but someday . . ha ha!

[Silver Blues]

Anytime, and thanks, I appreciate it. Me too, man, I have resistors and capacitors EVERYWHERE but have to order semiconductors and pots each time... :( Good thing I bought a ten pack of TL072s, at least...

--Silvie

PS I'm thinking I should stop signing my posts with "Silvie", I mean it's a nickname with an odd story and you people know my real name anyway.

[Silver Blues]

Pulled the Thunderhead. After pondering it I decided I didn't really like it. I have another one recently done, if in a little bit I decide I like the idea will post here. Thanks again for everything done and pending on this guys.

[Silver Blues]

Removed... I've made changes to all of these circuits and to my general pedal lineup. Thanks for anyone and everyone who's helped me, I couldn't have done anything without this site and the great people on it.