Motivation
This is the 12V Euro version of my NGF dual version. It uses the now obsolete LM1496 balanced modulator -demodulator. But you can still source them and I have some in my stock. So I decided to make a PCB and module. I started with the original Elektor Formant schematic published in "Formant Erweiterungen" p35ff. I left out the microphone and envelope follower part because I already have such modules. I have added input buffers and raised the signal level to my 10Vpp used throughout my system.
Specs and features
- Quad Ringmodulator
- 10Vpp input and output
- Runs on +/-12V and +/-15V
- Power consumption around 70mA each rail
Implementation
Schematic
Quad Ringmodulator schematic: Control board
Quad Ringmodulator schematic: Main board
Description:
This implementation follows closely the original Elektor Formant implementation. Refer to the original documentation if needed. You can find it on the net. My changes are the input buffers and the adaption to my 10Vpp signal level.
Calibration
- You need to adjust the trimmers TR1..8. They are used for canceling the input signal.
- Adjust a sine signal to about 1000Hz and 10Vpp signal level.
- Connect the signal to input IN1A (IN1B) and adjust TR1(TR3) such that the input signal can no longer be heard or seen (if you use a oscilloscope) at the output.
- Do the same with the other ringmodulator and trimmer.
Building hints
- None
Special parts
- The LM1496 is obsolete now, but you can still source them. Beware of counterfeits.
Download
Quad Ringmodulator control board documentation downloadQuad Ringmodulator control board Gerber files download
Quad Ringmodulator main board documentation download
Quad Ringmodulator main board Gerber files download
Quad Ringmodulator *.fpd file
Quad Ringmodulator: Front view
Quad Ringmodulator: Populated control PCB
Quad Ringmodulator: Populated main PCB
Quad Ringmodulator: Back view
Quad Ringmodulator: Half front view
