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Circuit building: stop using antique parts (2014)

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Re: Circuit building: stop using antique parts (2014)

#121

Post by PeanutNore »

TD-Linux wrote: post #108
AceJohnny2 wrote: post #83

I've recently gotten back into hobby electronics, trying to revive all that EE knowledge I haven't used in 15 years, and one thing I sorely lack is knowledge of common components to use. Online electronics stores are no help because of the overload of possible components. Is there some sort of Cookbook out there I could refer to for up-to-date examples of common circuits and electronic tasks? I mean, I otherwise tota…

A lot of manufacturers have parts designed as drop in replacements for older parts, sometimes even with similar looking part numbers. Another thing that I often do is use Digikey's search and check their stock quantity to find out what's "popular". For example, if I want an op amp, I'll go to that category on Digikey and then first enter a quantity and sort by price. Then I'll start adding constraints - for example,…

I'm using the MCP6002 to drive the ADC of an ATTiny85 for a guitar pedal that replicates Game Boy sounds. It's got both rail to rail input and output and it all works happily on 3.3v.

Re: Circuit building: stop using antique parts (2014)

#122

Post by foobarian »

Florin_Andrei wrote: post #25
mrob wrote: post #19

Earlier quoted context omitted.

What frequency are you PWMing at, and are you applying any analog filtering? I frequently get annoyed by slow PWMed lighting, and I wonder how other animals with possibly faster vision perceive it.

No analog filtering - that's how you keep things cold all the time. The frequency is either 500 Hz or 1000 Hz, I forget which (depends on Arduino type). I doubt there are any critters that can tell it's not continuous.

I find it useful to speed up the default Arduino PWM by changing the clock source. There are some useful details at http://www.righto.com/2009/07/secrets-of-arduino-pwm.html . Basically you should be able to drive it up to tens of KHz. I'm not sure how far up it remains linear but works well enough for lighting.

At default clock rates (clock/256) I can definitely see the flicker, especially through the lowest duty cycles.

Re: Circuit building: stop using antique parts (2014)

#123

Post by markrages »

wbl wrote: post #92
AceJohnny2 wrote: post #83

I've recently gotten back into hobby electronics, trying to revive all that EE knowledge I haven't used in 15 years, and one thing I sorely lack is knowledge of common components to use. Online electronics stores are no help because of the overload of possible components. Is there some sort of Cookbook out there I could refer to for up-to-date examples of common circuits and electronic tasks? I mean, I otherwise tota…

Horowitz and Hill third edition.

Also, searhc digikey and sort by quantity in stock, descending. The popular parts are the ones to use (if you don't have special requirements of course).

Re: Circuit building: stop using antique parts (2014)

#124

Post by retrogradeorbit »

There's still plenty of reason to use discontinued components in DIY. And that reason is the form of the component's package.

This is a problem for me when building high end audio circuits. A lot of the modern components are only available in surface mount forms. I find this with matched transistor packages. Like a matched quad. There are modern components, like AD's MAT14 [1], but if you are building your own circuits and using through hole components your ONLY choice is discontinued components. They simply are not made in a through hole package anymore.

At some point I'll be forced to move to surface mount, but at the moment getting old components is a lot easier. And those old components are as good as the new ones. Just different packages.

If anyone knows of a modern precision matched quad like the MAT14, but in a traditional package, please reply with the component!

[1] http://www.analog.com/media/en/technical-documentation/data-...

Re: Circuit building: stop using antique parts (2014)

#125

Post by retrogradeorbit »

PeanutNore wrote: post #49
bsder wrote: post #31

Earlier quoted context omitted.

> My perspective, not widely shared, is that JFETs in general have been made obsolete by depletion-mode MOSFETs, at least in audio circuits. A guitarist friend decided to "test" me once and put this in front of me and ask what it would sound like: http://el34world.com/charts/Schematics/files/randall/Randall... My immediate response was: "That looks like a really great amp from the mid 1980's--looks like it was design…

There definitely are people who want that buzzsaw sound. The Boss HM-2 pedal "chainsaw" sound is also having a moment right now. I'm not really into either, but I do like really saturated high gain sounds with a lot of compression.

HM-2 on bass is really good. If my memory serves, Kevin Shields used the HM-2 on bass on some My Bloody Valentine tracks.

Re: Circuit building: stop using antique parts (2014)

#126

Post by paulannesley »

mrob wrote: post #27
Florin_Andrei wrote: post #25

Earlier quoted context omitted.

No analog filtering - that's how you keep things cold all the time. The frequency is either 500 Hz or 1000 Hz, I forget which (depends on Arduino type). I doubt there are any critters that can tell it's not continuous.

If I count as a critter, I can easily tell the difference by moving my eyes and seeing the phantom array effect. If you're already using resistors for current limiting then putting a big enough capacitor across the LEDs will filter them without much difference in power consumption. I have no idea if the fish will care.

That effect drives me nuts too; but it seems to bother a minority of people. I've always assumed/guessed it's in the order of 50–100Hz; the 500–1000Hz mentioned may be fast enough to appear continuous to sensitive humans and maybe fish...

Re: Circuit building: stop using antique parts (2014)

#127

Post by TylerE »

ssalazar wrote: post #117
jwatte wrote: post #103

Earlier quoted context omitted.

ADC, MCU, DAC, done. Cheaper, too -- I think 50 cent ARMs can do that these days. Any pedal that isn't digital today is just nostalgia (like tube headphone amps and the like.) Digital is the clear better choice even for sound shaping.

Its not really that simple. Does the 50 cent ARM have accelerated floating point (though 32-bit fixed point is usually fine)? Does the analog design have a realizable digital model (not always possible/practical with non-linear systems)? Can a 50 cent ARM run the digital model at a high sample rate (needs to be 4-8x higher than normal audio rates to be able to filter out aliasing)?

A lot of times the "magic" is in the variance... the subtle things like drifting resistance values with temperature. Digital never does that right.

Re: Circuit building: stop using antique parts (2014)

#128

Post by retrogradeorbit »

jwatte wrote: post #103
bsder wrote: post #31

Earlier quoted context omitted.

> My perspective, not widely shared, is that JFETs in general have been made obsolete by depletion-mode MOSFETs, at least in audio circuits. A guitarist friend decided to "test" me once and put this in front of me and ask what it would sound like: http://el34world.com/charts/Schematics/files/randall/Randall... My immediate response was: "That looks like a really great amp from the mid 1980's--looks like it was design…

ADC, MCU, DAC, done. Cheaper, too -- I think 50 cent ARMs can do that these days. Any pedal that isn't digital today is just nostalgia (like tube headphone amps and the like.) Digital is the clear better choice even for sound shaping.

Hogwash. There are effects that analogue clearly destroys digital on. And the main one is distortion.

Digital is much more suited to time based effects. Analogue to harmonic distortion based effects.

You can keep your ADC/MCU/DAC distortion pedal. But if you are ever wondering why your guitar distortion sounds crap, this is it. But maybe you think it's fine. Anything sounds great with cotton-ears.

And tube amps only being for nostalgia? I wan't you to take your guitar, your digital distortion pedal and your digital amplifier and go to a rehearsal room with another guitarist who uses analogue distortion and a tube amp. Turn them both up loud. Jam together. Compare the tones. Compare the nature of how your amplifiers respond to your tone.

Sitting in your bedroom playing by yourself will never convince you of the short comings of your digital rig.

Re: Circuit building: stop using antique parts (2014)

#129

Post by pmorici »

retrogradeorbit wrote: post #124

There's still plenty of reason to use discontinued components in DIY. And that reason is the form of the component's package. This is a problem for me when building high end audio circuits. A lot of the modern components are only available in surface mount forms. I find this with matched transistor packages. Like a matched quad. There are modern components, like AD's MAT14 [1], but if you are building your own circui…

I disagree. Using a stencil and paste with a cheap toaster oven is easier to make high quality boards than with PTH and an iron. It's fast and almost always comes out great.

Re: Circuit building: stop using antique parts (2014)

#130

Post by pmorici »

AceJohnny2 wrote: post #83

I've recently gotten back into hobby electronics, trying to revive all that EE knowledge I haven't used in 15 years, and one thing I sorely lack is knowledge of common components to use. Online electronics stores are no help because of the overload of possible components. Is there some sort of Cookbook out there I could refer to for up-to-date examples of common circuits and electronic tasks? I mean, I otherwise tota…

The octopart.com Common Parts Library is a good place to start if you are looking for a generic part...

https://octopart.com/common-parts-library

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