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Interesting kits for DIY:

The 192 kHz audio ADC and DAC AD24QS (sold out) and DA24QS,
and the DA24QS' little brother DA24DS (96 kHz double speed)
The digital audio to USB interface DA2USB
Modules for finest PPM or VU meters or meter bridges: AMBM


Preview: It shall become the successor of the AD24QS and DA24QS:

 The ADDA2-QC Project

But I'm afraid that it will be a very long time before I can offer them - the semiconductor crisis... 😞

Vorschau: Es sollen die Nachfolger der AD24QS und DA24QS werden:

 Das Projekt ADDA2-QC

Aber ich fürchte, dass es sehr lange dauern wird, bis ich sie anbieten kann - die Halbleiterkrise... 😞

Versatile modules as kits for ambitious DIY multichannel meter bridges

  AMBM - The Analog Meter Bridge Module Project

  AMBM - Das Analog-Meterbridge-Modul-Projekt

DIY-kit with all SMDs populated

With LED bars containing 51 dual-color LEDs such a meter bridge is not only technically valuable but an exceptional eye-catcher, too.

PPM or VU measurements, bar or dot display, peak hold or not, high precision and many more features

Finally I have a great solution for how to get my ADC's (and other) digital audio signals into a PC:

  DA2USB - Digital Audio to USB Interface

  DA2USB - Digital-Audio-zu-USB Interface

DIY-kit with all SMDs populated

Driverless - no software to install
Up to 192 kHz/24 bit (Mac OS-X, Linux and Windows 10 from vers. 1709 on) and up to 96 kHz/24 bit and 192 kHz/16 bit (previous Windows)

Ein Versuchsaufbau, der interessante Ergebnisse geliefert hat:

 Bewegungs- und Richtungserkennung mit einem zweikanaligen Radar-Sensor

Nur aus Neugier habe ich mich mit solchen Rader-Sensoren befasst und war doch überrascht, was zu erreichen war.

An experimental setup that produced interesting results:

 Motion and direction detection with a dual-channel radar sensor

Just out of curiosity, I looked into such rader sensors and was surprised at what could be achieved.



An experimental setup, no replacemant for a DCF77-DO, but precise determination of e.g. OCXO-frequencies:

 Highly Accurate Reference Frequency from DCF77

Ein Versuchsaufbau, kein Ersatz für einen DCF77-DO, aber genaue Bestimmung von z. B. OCXO-Frequenzen:

 Hochgenaue Referenzfrequenz aus DCF77

Why of all things were the 74HCT9046 discontinued?

 Exakte und fehlerhafte Phasenkomparatoren

 Exact and Incorrect Phase Comparators

Except for the 74HCT9046, I only know ICs with phase comparators that generate jitter by design.

Sweep 24ns


Certainly neither a revolutionary development nor a stroke of genius:

 (Another) P48 to T12 Adapter

 (Noch ein) P48-zu-T12-Adapter

But I think it is a nice and practical solution for an XLR - XLR adapter.

Suitable for audio and measurement purposes - Input voltage noise approx. 0.41 nV/√Hz

 Entwicklung des LNPA60dB

 Design of the LNPA60dB

0.41 nV/√Hz are so little that sources with more than 10 Ω impedance noise more than this preamplifier!



Fast and meaningful azimuth and orthogonality measurement on pickups using synchronous rectification and a multiplex method:

 MPX-AZIO            MPX-AZIO

- Where do these azimuth and orthogonality errors come from -
- How to measure them -
- Introducing the prototype of a very convenient measuring device -

The LTC-Disp is a simple, pure display of the time codes, based on a suggestion from the PA sector (more precisely: the lighting department, which also works with it):

 LTC-Disp - Longitudinal Time Code Display

 LTC-Disp - Longitudinal Time Code Display

There is no finished device available, at least so far it is only a finished development!

This PPM (Peak Programme Meter) and Loudness Meter (LM) was a joint development with Estec GmbH. It is designed for professional use, mainly in radio and television studios and used by well-known broadcasting organisations.

 Loudness and PPM Meter LM128P

 Loudness und PPM Meter LM128P

Unfortunately the company Estec does not exist any more, but I still have some of these devices.
Also I take over the service for the delivered devices (but that was only once so far).

Battery powered, suitable for audio and measurement purposes:

 Low Noise FET Preamplifier

 Rauscharmer FET Vorverstärker

20 or 40 dB gain, DC capable, input voltage noise approx. 2.2 nV/√Hz

Resistors do not only exhibit thermal noise:

 Current Induced Resistor Noise

  Strominduziertes Widerstandsrauschen

A collection of experiences from experimental measurements
- No scientific treatise -

A crossover not only with the correct amplitude response, but also with a perfect pulse and step response:

Linear Amplitude and Phase IIR Crossover

A completely analog design

The FNIRSI 1013D could be a well-made small oscilloscope with excellent price/performance ratio, but it has such fatal flaws that I can only strongly advise against it:

 Hands off the FNIRSI 1013D

 Hände weg vom FNIRSI 1013D

In addition, there is an embarrassing answer from the manufacturer.

An interesting project turned out to become the most useful and indispensable device for my digital audio developments I ever made:

DASG - Digital Audio Sine Wave Generator

A very precise and flexible digital audio signal source which probably every digital audio system designer should have for exact signal processing tests. At least I couldn't miss it any more.

A delta sigma based analog 1 kHz sine wave generator with the main intention to generate a precise 1 kHz tone for calibration of analog level meters

DS1kGen - Precision 1 kHz Audio Sine Wave Generator

No kits or so available, but I can help for DIY

Praxistipp: Wie kann man einen oder mehrere Oszilloskop-Tastköpfe in SMD-Schaltung kontaktieren:

  Zwei Beine für den Tastkopf

- Wenn 2 Hände zu wenig sind -

The ADICON Project

An ADC not only for HiFi-enthusiasts

I realized that in many audio devices correlation measurement is incorrectly implemented:

False and Correct Audio Correlation Measurements

- About the difference between correlation meters and simple phase meters -

How is it done there, how is it done correctly and how big is the error?

Up to now my most ambitious project, not for DIY:

   8-Channel Fully Digital Parametrical Equalizer

Will this ever become a product? Let me know your opinion.

Mein bisher anspruchvollstes Projekt, nichts zum Nachbauen:

   8-kanaliger, voll-digitaler parametrischer Equalizer

Wird das jemals ein Produkt werden? Lasst mich eure Meinung wissen.

I still enjoy contact to the DIYs around the world:

   24 Bit / 192 kHz Audio ADC AD24QS with the optional preamplifier AD-IOA, the
   Audio 24 Bit / 192 kHz DAC DA24QS and the
   24 Bit / 96 kHz Audio DAC DA24DS

The ADC, AD-IOA and DAC kits are available

Ich habe immer noch viel Freude an Kontakt zu DIYs in der ganzen Welt:

   24 Bit / 192 kHz Audio-ADC AD24QS mit dem optionalen Vorverstärker AD-IOA, the
   24 Bit / 192 kHz Audio-DAC DA24QS and the
   24 Bit / 96 kHz Audio-DAC DA24DS

Bausätze für den ADC, AD-IOA und DAC sind erhältlich

I always wanted to know how to do it (and now I do):

Converting Analog into Digital (IIR) Filters - A Recipe (almost...) -


Simple Conversion of 1st Order Analog into Digital (IIR) Filters
Using impulse invariant transformation instead of bilinear transformation

Including my program AnaDigFilt.exe that helps to find out the digital coefficients and lets you explore what happens in case you "play" with them

My Java-Script filter design utility is able to dimension active high- and low-pass filters and now even single stage, 3rd order, low-pass filters:

Active Filter Design and Dimensioning

Low- ang High-pass Filter

Over a long time delta-sigma codecs appeared to be a sealed book for me - until I started to teach myself:

   An Introduction to Delta Sigma Converters

(   Eine Einführung in Delta-Sigma-Wandler)

The "RF-Wallpaper" was a valuable aid for me from my early beginnings in electronics on. Now I made it myself and do not need bad copies from books any more:

The RF-Wallpaper / Die HF-Tapete


A nomogram, an online-calculator and some background information about

Resistor Noise / Widerstandsrauschen


Something completely digital, growing more and more luxurious:

The new VFD-equipped DPLCM-VFD

An FPGA-Based Digital Audio Peak Level and Correlation Meter with many features

is the successor of the LED-equipped DPLCM

How to measure different parameters on a condensor microphone capsule:

Backplate Voltage Driven
Condenser Microphone Capsule Measurement (CM2)

An experiment to design

An RF-Circuit for Condenser Microphone Capsules

The concept of an

Extreme Low Noise Preamplifier

with down to 0.45 nV/Sqr(Hz) or even 0.37 nV/Sqr(Hz) of input voltage noise

Frequency responses can be measured much faster than with sweeped sine signals:

Instant Audio Frequency Response Measurements using Soundcards, FFT-Software and Multi-Sine Signals

Some additional equipment for audio measurements:

Audio Preamplifier
Weighting Filter Set
Universal Filter

  An analog-to-digital- and digital-to-analog converter for the USB (in German only):



   My little POV-Ray Project was made during a few holiday days. It's German, but there is not much to read, there is more to see.

2 small articles of mine, on Rod Elliott's site
Reverse RIAA Equaliser: How to use a needless phono input as a universal line input?
Transformerless Balanced Line Driver with Floating Output: Amplifier with transformer-like output properties

(Note: Rod's website has moved and the links are updated now.)

Tut mir leid, leider übersteuert

I was curious about the inside of such a battery pack (updated):

Analyzing a Chinese Battery Pack Clone (updated)

Repair tips for presumably frequently occurring defects:

  Repair Power Supply Spectrum Analyzer Advantest R3361
  Reparatur Netzteil Spektrumanalysator Advantest R3361
  Reparatur ELCO Thision, Fehler 160

Last update: April 11th, 2024 Questions? Suggestions? Email Me! Uwe Beis