Where i can find Crazy Larry and Analog Bit Crusher PCBs?

Fuzz Aldryn · January 27, 2009, 04:36:07 AM

... I would like to have some fries medium with mayo and a huge roll solder with flux core (but don't hand me that lead free sh**)

Cliff Schecht · January 27, 2009, 03:36:51 PM

Alright, finished. Here's a link to everything you'll need:
http://www.aronnelson.com/DIYFiles/up/Crazy_Larry.zip

Add ground plane drill holes wherever you need them, that's the idea behind a huge ground plane. It took a while to get those pots lined up nicely along the edge (as you can see, I just used trimpots with decently sized pads) but they should work fine. This is completely unverified, of course, so no warranty is included. Let me know if you have any problems!

Note: There is one jumper, at the bottom left corner, denoted by the red wire on top in the file "Crazy Larry parts and traces.pdf" file.

gigimarga · January 27, 2009, 04:55:51 PM

Fabulous!!! Wonderful!!! You're a little wizard!!!

Thx a lot! I hope i will build it very fast and i will report here the result!

Cliff Schecht · January 27, 2009, 07:43:30 PM

Do me a favor and check over the schematic carefully. I'm pretty dang sure it's all correct, but for your and my sanity, it'd be a good thing to double check. I can promise that if the schematic is correct, the layout is correct

.

oskar · January 28, 2009, 12:04:21 PM

Howdy!

Nice project!
I pop by here with a question...
What is the purpose of C7?

Oskar

Cliff Schecht · January 28, 2009, 05:30:07 PM

Quote from: oskar on January 28, 2009, 12:04:21 PM
Howdy!

Nice project!
I pop by here with a question...
What is the purpose of C7?

Oskar

Looks like it there to shift the fet chopper DC offset to around 0 V, which doesn't make sense because the op amp cant swing below ground.

On second though: I think it's there to give an averaging effect to the sample and hold output because when 1 uF is fed into an ultra-high resistance (10^12 ohms), it will act like an anti-aliasing filter. This cleans some of the stepiness your signal sees from the sample and hold circuit.

gigimarga · January 28, 2009, 07:04:34 PM

Quote from: Cliff Schecht on January 27, 2009, 07:43:30 PM
Do me a favor and check over the schematic carefully. I'm pretty dang sure it's all correct, but for your and my sanity, it'd be a good thing to double check. I can promise that if the schematic is correct, the layout is correct .

Thx a lot Cliff again!
I will check the schematic tomorrow, i hope.

Cliff Schecht · January 29, 2009, 03:22:01 PM

Another thought just popped into my head. Make sure to check the pin layout of whatever P-channel JFET's you use against the layouts I used on the board. Pin 1 is gate, pin 2 is source and pin 3 is drain. This is standard for the 2N548X (5484, 5485 and 5486), 2N545X (5457, 5458, 5459) and J201, for example.

gigimarga · January 30, 2009, 03:05:47 PM

Quote from: Cliff Schecht on January 29, 2009, 03:22:01 PM
Another thought just popped into my head. Make sure to check the pin layout of whatever P-channel JFET's you use against the layouts I used on the board. Pin 1 is gate, pin 2 is source and pin 3 is drain. This is standard for the 2N548X (5484, 5485 and 5486), 2N545X (5457, 5458, 5459) and J201, for example.

Thx a lot Cliff!
Unfortunately, i am in a delegation out of town, so only on monday/tuesday i will be able to check the schematic.

Cliff Schecht · February 08, 2009, 08:31:39 PM

Here is the finished (unverified) board, schematic and other associated files:
http://www.aronnelson.com/DIYFiles/up/Crazy_Larry.zip

Let me know if there are any problems reading where parts go, where to drill, etc..

gigimarga · February 09, 2009, 03:19:06 AM

Thx a lot Cliff!

I hope i will build it next week and i will post a report here as soon as i will finish!

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Where i can find Crazy Larry and Analog Bit Crusher PCBs?