Many circuits use J201 JFETs,Sadly the TO-92 package are out of production, and many of those that can be found online from China sources are so far out of specification that they do not work. Additionally testing shows wildly different specs regarding tolerance. Now you can simply use the cheap and readily available SMD SOT-23 package with ease.

In this final version of my "Atari punk Console" we add a simple potentiometer to the CV pin on the second oscillator and a jumper to add it into the 1st oscillator as well. This gives us a very wide frequency range to create tones. in final assembly I used rolled pin headers in place of the timing capacitors to allow for different values. You can season to your own taste.

This adapter was designed to allow an audiophile to enjoy modern SOIC audio grade opamps in any suitable application.I decided to make and share this PCB because I simply couldn't find one of these to use myself and would like others to also experience the ultimate joys of sonic audiophile perfection.PCBWAY is the perfect community to host my PCB, excellent speedy service and premium quality.

This is a two channel version of the the original dualOPA impedance converter here. This lets you take two discrete audio channels out of one microphone that has wither two capsules in it, or both sides of a dual diaphragm condenser capsule. Then you can create any pattern you like in post such as full Omni, Cardioid or Figure Eight. Or, any variation in between! It is very quiet using a dual OPA1642 opamp and is fully powered by Phantom Power coming in on the two channels from a mic preamp. There is one common ground connection. Here is the associated Instructable :

What is the OctoPill? The OctoPill is a Arduino Nano Shield that allows you to control anything from 4 to 8 devices using the most common 4 channel and 8 channel Relay modules. No programming necessary and simple through-hole soldering. It's compatible to work with the OctoBanger Software from Buttonbanger.com.What Can I use the OctoPill for?Museum ExhibitsPoint of Sale DisplaysHoliday Props & Lighting ControlInteractive DisplaysDJ Lighting and EffectsAtmospheric AnimationsEscape Room EffectsNeeded to workArduino Nano (Link)4 or 8 Channel Relay Board 4ch (Link) 8ch (Link)5v 2amp USB Charger (Link)Micro Usb Cable (Link)Octo Banger Software (Free) Direct Download (Link) HARDWARESerial MP3 Player (For High Quality Audio) (Link)MP3 player for high quality audio Micro SD Card ( To Store your High Quality Audio) Motion DetectorMat Switch/ Momentary SwitchArduino Nano 3.0Check Button Banger for more information : http://buttonbanger.com/?page_id=164Thanks you!-Eric Ghttp://buttonbanger.com/?page_id=164

This simple synth uses 3 555 timers, two as stepped sound drivers and one as a low frequency oscillator. Together with some timing caps and potentiometers for control you get a simple synth that you can hook up to a speaker and make some very interesting sounds.

From Robs Mods Youtube Channelhttps://www.youtube.com/channel/UCAwONoZRXEcaSvVYkMCxHTQVideo with descriptionhttps://www.youtube.com/watch?v=33L4sWdWLWwWebsite with Project PDFhttps://robkiddhomepage.wixsite.com/robkiddmusic/project-beroccaProject PDFhttps://16523fc6-ac2c-4fa9-ac46-96b5c75912c9.filesusr.com/ugd/1ac20e_6b7d4b2ccc884320b497ab27a6d35df5.pdfhttps://robkiddhomepage.wixsite.com/robkiddmusic/project-beroccahttps://www.youtube.com/channel/UCAwONoZRXEcaSvVYkMCxHTQ

This is the PCB for a dual operational amplifier circuit that will mount in a BM-800 body and interface with a condenser microphone capsule such as the TSB2555B and TSB165. These are Electret with no internal FET. Also it will work with true condenser capsules that require bias voltage. This has a 12 volt output that can be used to supply the bias circuitry. The build instructable is here And a video of it in action on four microphones is here https://youtu.be/7JmeEmgNlPw

An experimental 5-"key" keyboard for homemade synthesizer. Intended for use with magnetic induction reed switches, Hall Effect sensors, or other simple buttons and switches. Five channels can operate independently or fed by a common input and mixed toward a common output. In "mixdown" mode, you can use extra spaces/pads for resistors, diodes, etc. A large number of unconnected pads for other customizations. Part of my ongoing audio device experimentation (https://www.diysynthjunk.dev/).

We all like LED color lights and light shows. WLED firmware let you enjoy your LED lights and create incredable light show. Just look how great firmware is https://github.com/Aircoookie/WLED and what is greater it's improving every day with great community support! And now another great feature have been added to this project by group of developers sound reactive feedback.In my repository is always fresh update to stable version with recent features.

This is a simple metronome using a 555 timer. The RC component sets the tempo and a 1K pot allows volume control.

This is a just a simple tone control circuit that can be added to an existing project for better audio control.

This is the islet board for a 5F1 amplifier circuit. You put your caps and resistors on this board.

Designed this little module to add a line out to a RF lav mic belt pack I picked up cheap on eBay.Built with the parts list provided it has a gain factor of 51 (appx. 10mV in, 500mV out) with a noise level more than sufficient for audio applications. Runs off a single ended DC power supply from 2.7 to 5V, and can easily be adapted to other small signal amplification tasks in the audio frequency range by changing the biasing and feedback resistors.

This is a simple circuit that can protect your expensive speakers from annoying "pop" sound that you hear when you turn on your audio amplifier it will provide this protections time delay about 3 to 4 seconds, DC detect in case the amplifier fails it will automatically will shut off the speaker from you audio amplifier and lastly thermal protection. The original schematic use a resistor combination with a zener diode as supply media and what I did is kept that option and add a voltage regulator as a better and easiest way to supply voltage to the circuit. To make it a lot easier on you just use the voltage regulator and not the resistor/ zener combination, install D11,6,2,1 do not install ZD2 and do not install D3. The LED can be any color you like I like green the LED will give you a status of the circuit by blinking a steady blinking is normal operation and if there is a DC detect it will turn off the speaker and begin blinking see the video this is the first prototype and works really well the BOM is update recently with new values of resistors. The AC input is from 12V to 27V AC you will need a separate small transformer or a secondaries winding from your toroidal transformer to feed the speaker protection please give a like this design I spend many weeks making the layout I hope you guys like it :) one more thing the thermal switch you connect them in series one to the left channel and the other to the right channel of the amplifier relays are 12V DC see BOM for more information.The Automatic speaker protection gerbers files are the new version updated to PCB version 1.3 and resistor and caps values updated don't mind about the second video all values are been updated.first videosecond video

Hi this the the second part of the audio amplifier the Greenamp v1.2 schematic this is the power audio board this design can use BJT or mosfets power semiconductors just fallow the schematic and you will figure it out no difficult to build the photo you see is actually my build, the supply voltage is from 40V DC up to 85V DC positive and negative rails, the bias adjustment is simple to do just read voltage drop on one of the emitter resistors 0.22 ohm to 26mV DC. There is a website that has more information about this design many people build this audio amplifier. The size of the PCB is 254 mm x 80 mm. I recommended to try BJT if you are not comfortable matching V-mosfets I will leave the simulation of this amp design in mosfet and BJT power audio transistors the maximum power that can deliver this design depends on the power supply you are gonna use I recomended a 800 to 950VA toroidal transformer but this design can work just fine with a 600VA toroidal transformer according to simulation can provide close to 600 watts @4 ohms but with the experience I have I will say that can provide clean 350W @4 ohms with really low THD there is a lot of good information about this deisgn here on this link from diyaudio.com the designer is Mr. Ostripper https://www.diyaudio.com/forums/solid-state/248105-slewmaster-cfa-vs-vfa-rumble.html