Background Tuning instructions in the service manual are actually just fine. These are marginally easier to follow. What you need Preparations Step by Step Step 1 – Key Assigner (KLM-256) CV Connect the positive lead of your DVM (using a hook clip) to the right side of R8. Connect the DVM ground to GND at […]
Background There are no tuning instructions in the service manual. The trimmers have unusual names, so it’s not obvious what do when opening it up. Here you go: What you need Preparations Step by Step Step 1 – Keyboard CV Connect the positive lead of your DVM (using a hook clip) somewhere on the grey […]
When using a hardware tuner, you can ditch the unintuitive tuning instructions in the service manual. In my case that is a Peterson Strobostomp, but any tuner you trust can be used. Software, Apps, computers: Sometimes software tuners have trouble displaying very low, as well as high, frequencies. Often they are more sensitive to overtones, […]
The two tuning procedures (Production and Simplified methods) provided by Sequential Circuits in the Rev 2 service manual are complex, easily misinterpreted, and abstract – if you don’t have an intuitive sense of what you are doing, it’s hard to tell when you are not doing something right. It’s easy to miss a step or […]
Background When tuning the Teisco SX-400, it’s hard to know what voice you’re currently hearing. Also you need to know which trimmer to use for upper end of the keyboard, and which to use for lower end. There are no tuning instructions in the Service Manual (which by the way is not much more than […]
The tuning of a Korg PolySix is mostly a tedious process. Let’s go in-depth to make it even worse. The tuning process described here is normally not necessary, but if you have replaced some components on the Voice PCB this might be your last resort. Sources of information The PolySix Service Manual. There is some […]
The FastLED Library for Arduino and other microcontrollers is used for controlling LED-strips with one to hundreds of individually addressable RGB LEDs. Here is a visual reference to the colors that are pre-defined within FastLED. In C++ they can be accessed by name, like this: The colors in this list appear in the same order […]
How to make a replacement for the 82S123 ROM chip (ADS-1 board – U19) in Ursa Major Space Station SST-282, using an 22v10 Programmable Logic chip and a cheap EPROM programmer. I used Atmel ATF22v10CQZ-20PU and the common TL866iiPlus. This is not a step-by-step guide, you are expected to know how to use an EPROM […]
This page compares the Roland MKS-7 to the Roland Juno-106. To understand it, you need to know the Juno-106. Some people say the MKS-7 is the rack version of Juno-106. But it’s more… and less. The Roland MKS-7 was allegedly intended for MIDI-file playback and karaoke, thus being a consumer market product. The voicing hardware […]
While servicing an Arp Sequencer 1621, I noticed that the three button switches were in a bad shape. One button press would produce anything from one to six signal changes. These switches can’t be sourced nowadays. The switches are glued together from factory so they can’t be opened. One possible fix would be to fit […]
Disclaimer: There may be a better way to tune the Korg Lambda. My method is a bit “hit and miss”. Still it took less than five minutes to accomplish. Background The Lambda is not a VCO->Filter->VCA synthesizer, it’s constructed lika an organ / string machine. The tuning procedure is different and often simpler on an […]
It was pointed out to me that there is already a modification devised by Korg for this purpose. While my modification works, you should probably stick to Korg’s original Engineering Change Note, even though it’s a bit more complex. The Korg Poly-61 has the same type of battery as the Korg Polysix, the type that […]
Disclaimer: I have no idea. Maybe this can be done better. But here’s my best shot. Background There is not much technical information around about this very rare synth. In order to figure out how to tune it, I had to remove the front plate which is a lot of work. This article is an […]
Descriptions of Individual Audio Outputs modifications for the Roland TR-505 have been around for a while. I searched the web for sources that describe how to do the mod: https://www.circuitbenders.co.uk/drummachine/TR505.html https://masutopedals.wordpress.com/2017/04/20/roland-tr-505-stuff/ There are many sources talking about having it done, without explaining how: http://www.burnkit2600.com/tr-505/#outputs http://gumielectronic.net/tr505.html The problem However, the modifications that are described share one […]
This drum machine from 1981 is a close relative of Roland CR-78 and TR-808. It has a couple shortcomings, such as no user editable sounds, a Snare Drum with a lot of tone (what is called “Snappy” on 808) but a lack of noise / high frequency content. It sounds more like a tom. Also […]
Arduino files download: Sonoff_toaster_timer First install ESP8266 support for Arduino IDE. Follow these instructions: https://github.com/esp8266/Arduino Reprogram Sonoff Smart Switch with Web Server. I didn’t use this in the end, but learned the basics: https://randomnerdtutorials.com/reprogram-sonoff-smart-switch-with-web-server/ ESP8266 ajax – update part of web page without refreshing. The main source for my toaster’s html page: https://circuits4you.com/2018/02/04/esp8266-ajax-update-part-of-web-page-without-refreshing/ ESP8266 Timer […]
Andreas Gaunitz email Phone (Sweden) +46708667601
It seems Doepfer cut some corners when designing the MCV4 MIDI to CV interface. Firstly the MCV4’s gate voltage is to low to drive the Roland SH5 gate input. This can be remedied by opening up the interface to move a jumper, and then replacing the 9v power supply with a 12 volt one. After that the […]
A mid-80’s drum machine, modified for MIDI-controlled sound chip selection, circuit bending and pitch. Any MIDI sequencer or keyboard can be used. No changes are made to the exterior of the machine. The Kawai R-100 drum machine classic was modified using an Arduino Nano, the circuitbenders.co.uk “R-ROM Switcher” and a HC-SR08 board. The Nano reads incoming note […]
Two unusual electronic instruments that were part of a greater ensemble, built for an exhibition in China. Idea and hardware by Daniel Araya. Programming and I/O-electronics by 9bit. The MIDI Control Surface The Control Surface is a Standard MIDI Interface compliant unit, built to interface with a MAX MSP patch on a host computer. The […]