@_electroidiot

Hobby Electronics for the Complete Idiot

DIY Electronics Blog – Audio, Synth DIY, Guitar Pedals, Circuit Analysis And More!

Idiot’s Guide to the 555 Timer IC

Getting Started with the 555 Timer – Everything You Need to Know The 555 Timer is one of the most popular integrated circuits of all time. Its versatility has made it a favourite among hobbyists, who keep discovering creative uses for the chip beyond its original purpose. No matter where your interests lie in the…
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December 16, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 7 – Voltage Controlled Amplifier, White Noise Source, and Final Assembly

In this 7th part of the Noise Toaster Lo-Fi Synth analysis, we’ll build the last two circuit sections and finish the PCB assembly. We started with the power supply and audio amplifier sections back in Part 2, and went on to build the VCO, LFO, ARG, and VCF circuits. We now turn our attention to…
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November 12, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 6 – Voltage Controlled Filter

So far in this multi-part series on the MFOS Noise Toaster Lo-Fi Analog Synthesizer, we built and analyzed the Audio Amplifier, VCO, LFO, and AREG circuits. We were able to explore some neat frequency modulation effects by using the LFO and AREG to mess with the VCO Frequency. Now, let’s step this up a notch…
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September 22, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 5 – Attack Release Envelope Generator

Adding an LFO to modulate our VCO‘s frequency has already made our synth much more interesting. Let’s step things up a notch by adding another CV source – an AREG or Attack Release Envelope Generator. This is part 5 of a multi-part series about the MFOS Noise Toaster Lo-Fi Analog Synthesizer. Make sure to check…
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September 7, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 4 – Low Frequency Oscillator (LFO) Circuit Analysis

Previously in this multi-part series on the Music from Outer Space Noise Toaster Lo-Fi Analog Synthesizer, we built and analyzed the main Voltage Controlled Oscillator (VCO) circuit. The VCO can be modulated by the Attack Release Envelope Generator (AREG) and the Low Frequency Oscillator (LFO). In this blog post we will build and analyze the…
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August 1, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 3 – CV Mixer, Expo. Converter, and VCO

The Noise Toaster is built around a ramp core analog oscillator which acts as the synth’s main signal source. The frequency can be modulated by control voltages from various sources – this makes it a Voltage Controlled Oscillator (VCO). In this article, we take an in-depth look at how the Noise Toaster’s VCO circuit functions.…
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July 24, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 2 – Power Supply and Audio Power Amplifier

Previously in this series of posts, we looked at the Noise Toaster Lo-Fi Analog Synth at a block diagram level and introduced the PCB layout and enclosure for the _electroidiot version of this classic synth by Ray Wilson of Music from Outer Space. We now begin building the Noise Toaster by ensuring that the correct…
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July 17, 2023
Noise Toaster Lo-Fi Synth Build and Analysis: Part 1 – Introduction

The Noise Toaster is a Lo-Fi analog synthesizer designed by the late Ray Wilson of Music from Outer Space. The project is covered in Wilson’s excellent book “Make: Analog Synthesizers” as an ideal starting point in the world of Synth DIY. As I have been learning about the basics of synthesizer circuits, I decided to…
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July 16, 2023
Hello world!

Welcome to _electroidiot, a new blog about DIY electronics.
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March 25, 2023

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From the ‘gram

_electroidiot

Here is a really cool and rare little amp I worked

Here is a really cool and rare little amp I worked on recently. The Marshall Studio 15 was produced between 1985-1992. This example came to me in a non-functional state. There were a couple of clearly burnt resistors and some investigation revealed that both the output transformer and the mains transformer had failed. I got the transformers re-wound, changed the burnt resistors, and replaced all the electrolytic capacitors. The B voltage+ dropping resistor had to be adjusted to get the voltages closer to spec with the rewound transformer. One of the output tubes soon failed after the amp was first powered up and had to be replaced. Finally, I set the output stage bias and the amp was good to go. The owner @ferzad was super pleased with the sound.
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#vintageamps #tubeamp #röhrenverstärker #röhrentechnik #guitartech #amptech #vintageaudio #marshallstudio15 #amprepair #becausetone #knowyourtone #audioelectronics #valveamp #tubeamps

Idiot's guide to the 555 Timer. Read the full blog

Idiot's guide to the 555 Timer. Read the full blog post on electrioidiot.com –https://bit.ly/480yQjh

Noise Toaster Lo-Fi Synth Build and Analysis Part

Noise Toaster Lo-Fi Synth Build and Analysis Part 8 – Voltage Controlled Amplifier, White Noise Source, and Final Assembly. Read more on electroidiot.com: https://bit.ly/476OQzL

PCB Fabrication kindly sponsored by @pcbway

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Anal

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Analysis Part 7 – VCF. Read the full blog post on www.electroidiot.com: bit.ly/48s0NBq

PCB Fabrication kindly sponsored by @pcbway

Electronics Workbench

Electronics Workbench

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Anal

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Analysis Part 6 – AREG. Read the full blog post on www.electroidiot.com: https://bit.ly/3rQ2mIz

PCB Fabrication kindly sponsored by @pcbway

Here's a really cool amp I got to work on recently

Here's a really cool amp I got to work on recently – A Soldano clone that was a partially built personal project of Aditiya from @animalfactoryamps . I wired up the power supply and output stage. The power and output transformer windings were unlabelled and had to be worked out. The DC heater circuit was a bit tricky to get working correctly as we had problems with the rectifier heating up and heater voltages being low. It's all sorted now after some trial and error. The amp sounds amazing and is crazy loud. We used NOS BEL made in India 12AX7s and NOS US GE 6L6s.
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#tubeamp #valveamps #ampbuilder #amptech #guitartech #vintageaudio #soldano #sloclone #ampbuilder #ampbuilding #knowyourtone #becausetone #boutiqueamps #guitardiy #pedaldiy #handwired #valveaudio #radioelectronics #röhrenradio #vacuumtube #tubelove #antiqueelectronics #vintageelectronics #12ax7 #6l6gc #vintageaudio

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Anal

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Analysis Part 5 – LFO. Read the full blog post on www.electroidiot.com: https://bit.ly/3rQ2mIz

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Anal

MFOS Noise Toaster Lo-Fi Analog Synth Circuit Analysis Part 4 – CV Mixer, Exponential Converter, and VCO. Read the full blog post on www.electroidiot.com: bit.ly/472mSp9

I devised this set of special perf-boards and matc

I devised this set of special perf-boards and matching universal Eurorack face-plates as a quick and easy way to build Eurorack modules. Two two boards can be sandwiched using SIL headers. The top board uses a universal component footprint that takes 9mm vertical potentiometers, Thonk style jacks, and SMTS switches. The pads are routed to the pin headers to connect the top and bottom boards. Boards fabricated by @pcbway. Laser cut face-plate from @robu.in_
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#synthlove #synthdesign #synthdiy #Eurorack #eurorackdiy #modularsynth #modulardiy #diyfever #electronicsdiy #hobbyelectronics #eurorackmodule #prototyping #hardwaredesign #hardwarehacking #productdesign #musictechnology #diysynth #makermovement #electronicsengineering #diymusic #pcbdesign #opensourcehardware

Work in progress – assembling and testing the MFOS

Work in progress - assembling and testing the MFOS Noise Toaster _electroidiot version. VCO, LFO, ARG done so far. Need to get cracking with the VCF, VCA, and the WNS section. Board fabrication was kindly sponsored by @pcbway. The turnaround time and quality of the boards is fantastic.
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#syntdiy #synthlove #diysynth #eurorackdiy #electronicsprojects #electronicsworkbench #analogsynth #analogelectronics #vintageelectronics #makersmovement #synthindia #lofisynth #mfos #noisetoaster #audioelectronics #pcbway #electronicsengineering #circuitbent

MFOS Noise Toaster Lo-Fi Analog Synth Part 3 – P

MFOS Noise Toaster Lo-Fi Analog Synth Part 3 – Power Supply and Audio Output Amplifier. We begin building the Noise Toaster by ensuring that the correct power rails are present for the various parts of the circuit, and that we have a way to hear the noises our synth generates. Read more at electroidiot.com: https://tinyurl.com/49vdkpw3

MFOS Noise Toaster Lo-FI Analog Synth Part 2 – P

MFOS Noise Toaster Lo-FI Analog Synth Part 2 – PCB and Enclosure Design. I first posted about the Noise Toaster back in December 2022. Unfortunately the project went on the backburner, but now I have finally had some time to work on it and have some big updates. Read more on electroidiot.com: https://tinyurl.com/4bkcmb27

@animalfactoryamps is showing off some SICK new pe

@animalfactoryamps is showing off some SICK new pedal prototypes at @superbooth_berlin ! I had the privilege of helping put these together at the AFA HQ in Bombay.
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#guitargear #guitarelectronics #diyfever #audioelectronics #circuitbent #becausetone #knowyourtone #fuzzlove #fuzzaddict #gearjunkie #Eurorack #diyguitarpedals #boutiquepedals #pedalbuilder #prototyping #allinthenameofrock #guitarelectronics #metalaf #toneaddict #pedaljunkie

#timelapse of my perfboard build of the @moritzkle

#timelapse of my perfboard build of the @moritzklein0 / @ericasynths EDU DIY VCO circuit....
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#synthdiy #eurorackdiy #soldering #electronics #synthlove

#workinprogress learning #fusion360 by designing a

#workinprogress learning #fusion360 by designing a 3D printable case for a portable analog synth. Takes 20HP Eurorack format plates...
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#synthdiy #Eurorack #eurorackdiy #modularsynth #productdesign #3dprinting #additivemanufacturing #diyelectronics #analogsynthesizer #diyaudio #diyfever #diypedals #synthdesign #cad #fusion360 #superbooth #makenoise #Modulardiy

What would you like to learn about Synth DIY? Let

What would you like to learn about Synth DIY? Let me know in the comments below 👇

Building cheap and easy Eurorack case and panels: bit.ly/3FPX43E

#educationalanimation #eurorackdiy #diyelectronics #ModularSynth #Eurorack

Modular Synth From Scratch Part 3 – VCO. After b

Modular Synth From Scratch Part 3 – VCO. After building the DIY Eurorack case and power supply, I could finally start putting together some modules. First of all, we need a signal source, so I have begun by building the VCO. I plan on copying the @ericasynths / @moritzklein0 EDU DIY kits' circuits as they are well documented and use common parts. Here are my notes about the VCO circuit. Read more below:

1. The sawtooth core VCO is based on the CD40106 Schmitt trigger IC. The trigger's output goes high when the input is below around 1/3rd of VDD, and low when the input is above around 2/3rd of VDD. A diode in the feedback loop quickly charges a capacitor at the input when the output is high. When the cap charges to above the threshold voltage, the output goes low and the cap begins to discharge slowly through the parallel resistor. Since the output is taken from the Schmitt trigger input, it is a sawtooth shape.

2. Synthesizers use the volt per octave standard to relate linear voltages to exponential differences between the frequencies of musical notes. Basically, every half-step corresponds to an increase of 83mV. Since a BJT's VBE-Ic relationship is exponential, we can replace the resistor with an NPN to make the oscillator voltage controlled.

3. The final VCO circuit adds a PNP emitter-follower before the NPN to provide temperate compensation. Note that since T2 needs to biased at around 350mV for correct Vin/Iout, T1 needs to be biased at around -150mV to compensate for its VBE drop. The sawtooth output is buffered and amplified by two op-amp stages.

4. The input circuit is a combination of a 4-input passive mixer and a voltage divider. Its function is to correctly bias T1, as well as correctly scale down the CV inputs and tuning control outputs. R17 is multi-turn trim pot that is used to bias the VCO so that it correctly follows the volt-per-octave standard.

Continued in comments...

Modular Synth From Scratch Part 2 – Building a

Modular Synth From Scratch Part 2 – Building a cheap Eurorack case, PSU, and cables. My main goal with this project is to learn about the circuitry behind basic synth modules. However, since "proper" powered Eurorack cases were out of my budget, I had to build something myself to get started. Here's what I learnt along the way. Read more below:

1. The basic construction of the case is based on a video by LOOKMUMNOCOMPUTER. I adjusted his design to work for the Eurorack format by making sure that the vertical spacing between rails was correct to accommodate the standard Eurorack size of 128.5mm. I also decided to use aluminum U-channels as rails instead of wood strips as in LOOKMUMNOCOMPUTER's video.

The measurements shown here assume a plywood thickness of 10mm. If you would like to build a similar case but need to use thicker or thinner material, the measurements will need to be adjusted accordingly to ensure that the vertical distance remains around 129mm to accommodate modules of 128.5mm.

I also decided to add a pair of speakers to my case, although this is not an usual feature of Eurorack cases. This is to facilitate easy experimentation and testing without the need for setting up an external mixer, amplifier, and speaker system.

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Modular Synth From Scratch – Eurorack Basics. T

Modular Synth From Scratch – Eurorack Basics. To a newcomer, the world of modular synthesizers and synth DIY can seem quite overwhelming, or at-least it did to me when I first began to dip my feet into its mysteries. Although I am now much less intimidated by the subject, I am still very much a synth newbie. To change this, I have decided to undertake this project in which I attempt to build an entire Eurorack modular synth setup at home, completely from scratch – and share my learnings with the world as I go along. Read more below:

1 – As you are probably aware, Eurorack is a format for synthesizer modules based on the Eurocard standard, originally developed for industrial electronics. Essentially, standardised front panel and rack sizes, as well as power supply requirements, allow the user to put together their own synthesizer using various modules. A "rack" or case usually has an on-board power supply and the various modules can be connected together with 3.5mm mono cables to create a "patch". R a. The front panel or faceplate height should be 128.5mm exactly, this corresponds to 3U, or 3 rack units (rounded off) as per the Eurocard spec.

b. The front panel width should be a multiple of 5.08mm. This corresponds to 1HP or horizontal pitch. For example, some common module sizes include 8HP (40.64mm), 12HP(60.96mm), and 20HP(101.60mm).

c. Modules are screwed onto the rails to keep them in place. A common thread size is M3, and special screws with large knurled heads are often used. To ensure that the mounting holes on the module faceplate line up correctly with the threaded holes on the rails, the mounting holes' centres should be exactly 3mm away the top or bottom edge of the faceplate. The leftmost holes' centres should be 7.5mm from the left edge, and the space between the leftmost and rightmost holes' centres should be an exact multiple of 5.08mm.

d. The module's circuit board is held onto the faceplate by the nuts and washers of the potentiometers, jacks, etc… To prevent interference with neighbouring modules and rails, the PCB should have at least 11mm clearance at the top and bottom, and 0.5mm on the sides.

Continued in comments...

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