Thanks! I just make vector drawings in Inkscape/Adobe Illustrator!
Hey hey :P
No worries, thanks for reading!
Awesome! For integrating into smaller form factors, I'd seriously consider Class D amplifiers over Class A/B. Far more efficiency means less heat (and less heatsinking), lower voltages for equivalent volumes and (often) fewer components needed. However, the best Class D chips are typically SMD/SMT devices, which can be trouble if you're used to through-hole components. Try the TPA3125 from TI to see what can be done! (http://www.ti.com/lit/ds/symlink/tpa3125d2.pdf)
Ha ha ha, precisely! I don't know how many pairs of headphones I eradicated before making my Headphone Dummy Load:https://www.instructables.com/id/Headphone-Dummy-L...Spot on - an 8 or 4 ohm resistor isn't electrically the same as an equivalent speaker, but a much more consistent load to drive for testing purposes. Non-inductive resistors in particular provide consistent testing results across amplifiers and is industry standard when benchmarking amplifier capabilities. A dummy load like this means little fear of damaging a real speaker (high power resistors can take some serious punishment) and best of all - silence! No full-volume 1kHz sine waves blasting your eardrums while testing :)
Tales From the Chip: LM1875 Audio AmplifierView Instructable »
No problem! The LM1875 Instructable is almost finished, will be up in a day or two.
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Thanks for the feedback! I deliberately use both terms in the article. I use "resistance" to refer to the resistors themselves and considerations around which ones to use (for the sake of avoiding confusion), but as "impedance" with regards to how an amplifier or source "sees" the load in an AC circuit, which is actually the more correct usage. Check this out for clarity!http://www.electronics-tutorials.ws/resistor/res_8.html
Thank you for the clarification! I've updated the article correspondingly :)
Thanks! Yeah, I've become an instrumentation nerd recently - they seriously help speed up prototyping. Cheers!
Headphone Dummy LoadView Instructable »
DIY External Volume ControlView Instructable »
Yeah, the obsession with wattage as it relates to volume is really bewildering, but you can understand why the marketing departments need to latch on to something somewhat relatable. I honestly don't know why anyone would need a 300W speaker in say, their living room.
Ah man, thanks for the trip down memory lane! I don't suppose you still have your chop-shop headphones?
Cheers - no problem! I've got a bunch of classic audio and general-use chips I'd love to write about, as well as some details about audio electronics in general.
Oh cool, that piggybacking idea is awesome, will investigate!
Yeah, I've got a pile of these lying around :) That being said, "old" doesn't mean "useless", and there is certainly a lot to be learned about audio electronics by understanding some of its more basic components, particularly one like the LM386 which has a very low barrier to entry. A great place to start, with little upfront cost and few extra components required. From there you can of course graduate to your dual LM4780 monoblock beasts!
Ha ha, yeah - I built the circuit before drawing out the schematic, so had the benefit of neatening things up and simplifying the layout somewhat. The two are electrically identical, however. And as long as the 0.1uF cap is between the output path and ground, it should still work like a charm. Thanks for the comment!
Thanks for your feedback! Cheers :)
Great, thanks man!
It's just the most bare-bones 555 circuit you can get - blinking an LED on and off :) This was just put together to test the relationship between the resistor/capacitor network on the timing itself.
You're correct! A more accurate term in my context would have been "loudness" as well as sound-pressure level (dB-SPL). That being said, dB is useful when talking relative terms or comparing levels, which was my intention here. I'll attempt to clarify :)
Oh, awesome - your Instructable looks well worth a read! Thanks for the link, and the kind words!
Great tutorial - clear and comprehensive. Nicely done!
Ha ha, blowing stuff up and starting again is all part of the fun. Thanks for sharing your build - seriously cool stuff. Jumpers are also a good idea - probably a safer option than my DIP switches.
Spot on - you'd need to select the potentiometers quite carefully, but that would work no problem. As for a little on-board voltmeter you would almost certainly have a small forward voltage drop you'd have to work around, but of course with the potentiometers you can just dial it a little higher and maintain the output you need.
Thanks for the feedback - yeah, no doubt jumpers are the safer option. I like to live dangerously, apparently! Fortunately I haven't had a DIP switch accident yet ;)
Beautiful, elegant solution!
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Tales From the Chip: LM386 Audio AmplifierView Instructable »
Awesome! Looks great - love the inclusion of the battery.
Awesome, looks great!
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Cheers! Such a great little idea
Your design is lovely - simple, minimal, but striking. Looks like a genuine piece of high-end equipment. Well done!
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Oh wow, this is awesome! Thanks for crunching the numbers - this is by far preferable. Well done, thanks for sharing!
Awesome, thanks very much! Hope you get around to making one (or something like it) soon!
Thanks @itzzzmee! My variable power supply needs are a little different - I work a lot with DIY audio projects, where a higher powered amplifier can often require around ~36V, if not higher. So my DIY variable supply will need to be pretty beefy. When I get around to making that, I'll stick it on Instructables too. Thanks for the comments!
My pleasure, hope you get around to building one! Yeah, certainly not the best looker on the market, but you can't balk at $6 :)
Great idea! The more versatile the better. I find I only really need a variable output when working with higher voltages - almost all the projects I tinker with need 3.3, 5 or 9 volts - but this would go a long way to catering for the more niche scenarios.
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