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Post by Ethan Winer on Apr 14, 2024 20:45:53 GMT
Thanks for the update, and I agree that a Zener diode makes sense.
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Post by Ethan Winer on Mar 27, 2024 17:26:18 GMT
Thanks for the update. My best suggestion is to get LTspice and compare its "oscilloscope view" with what you see on your own board with a real 'scope. Maybe first record your guitar so you have an identical signal to feed your board, and as a Wave file version to feed the LTspice simulation.
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Post by Ethan Winer on Mar 16, 2024 18:51:43 GMT
Yes, PC board layout is very much an art. It's also a lot of fun! As I mentioned in the article, it's not unlike playing chess where you have to plan several movers ahead.
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Post by Ethan Winer on Mar 13, 2024 17:43:30 GMT
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Post by Ethan Winer on Mar 12, 2024 17:35:24 GMT
Sounds like a plan. I'll point out that 147k is in fact a standard 1 percent value: Also, test points area available in a large variety of shapes and sizes. I used these tiny ones for my last surface mounted project: www.digikey.com/en/products/detail/keystone-electronics/5019/3907343And yes, please do keep us updated with your progress. Believe it or not, having you be the first to build this for real is exciting for me too. I bet audioXpress magazine would welcome an article by you as a follow-up to my original article.
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Post by Ethan Winer on Mar 11, 2024 21:22:28 GMT
You didn't mention if you're using surface mounted parts or not, but if you are, and you're concerned about wasting valuable PCB space, this trimpot is only 3mm in diameter! www.bourns.com/pdfs/TC33.pdfI bought some for a project and they work well and are easy to adjust - using a small screwdriver of course!
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Post by Ethan Winer on Mar 11, 2024 21:18:09 GMT
Sorry for the delay Paul, but I'm here now. I never built any of the guitar synthesizer circuits for real. They all exist only as LTspice simulations. Do you have LTspice? The program accepts Wave files as input, so you can record your own guitar (direct from the pickup) and use that to tweak the pick detector and noise gate to be sure they work the way you need. I don't think a few pF of capacitance on your PCB will be a problem because these circuits are not super high impedance. Even R19 in the noise gate at 2M won't be an issue because it's connected almost directly to 15 nF. As for R35, you could try values between, say, 2k and 10k, or use a 10k trimpot. That's why I suggested using LTspice with a Wave file of your actual guitar. But adjust the Wave file's dB level so the voltage at the plus input to U1 is about the same as comes out of your guitar. All of the op-amps in these circuits use the "Universal Op-Amp 2" model that comes with LTspice. This is not an FET op-amp, though it works fine in my simulations. I just happen to be working on a new book about audio circuits with LTspice, so I have this list of parameters handy: U7 and U8 are the same op-amp. Comparators don't generally need feedback, and when they do it's positive for hysteresis as with U7, mentioned in the article text. So sure, just use the same op-amp for everything. The TL084 seems excellent. And finally yes, 12 volts should be fine. The Wave file input will always be 2V peak to peak. But you might need to change the resistors at U8.
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Post by Ethan Winer on Mar 9, 2024 18:47:47 GMT
That makes sense.
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Post by Ethan Winer on Mar 9, 2024 17:52:27 GMT
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Post by Ethan Winer on Mar 7, 2024 19:56:10 GMT
I'm not aware of any flooring material other than carpet that will improve acoustics.
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Post by Ethan Winer on Feb 16, 2024 21:31:02 GMT
Please don't go away forever. At least come back after you finish to let us know what happened.
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Post by Ethan Winer on Feb 16, 2024 19:59:10 GMT
I wouldn't overthink this. Bass waves are large and get to everywhere in a room. So angles etc don't have as much effect as you might think. If you can post a link to a photo of the walls, I might have more to offer.
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Post by Ethan Winer on Feb 16, 2024 19:56:30 GMT
Yes, filling that void fully with blow-in "fluffy" type insulation will absolutely make a real improvement. I can't tell you how much reduction to expect, and it probably depends on several variables. But your assessment that "it would resonate/reverberate and gosh knows what else" is absolutely valid. When you contact a contractor to do this, they may have a better idea of how much noise reduction to expect. But whatever the amount is, I'm confident it will be worth the effort and expense.
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Post by Ethan Winer on Dec 7, 2023 21:03:55 GMT
in a well-treated room my bet is that differences in gear will be more discernible. Absolutely. And as you implied, most gear these days is clean enough to be audibly transparent. To be notified when someone replies to a thread you're in, click Profile in the top blue bar, then Edit Profile near the upper right, then Notifications. You'll see a list of events you can ask to be emailed about.
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Post by Ethan Winer on Dec 6, 2023 21:46:45 GMT
Thanks Rock for helping out here. I had a few emails with Rick, and he told me you've been helping him.
Rick, you asked if I had anything to add, and I don't. Everything Rock said is correct.
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