Welcome to my place!

Audio Resource Jan Didden

It's great to have you here!

This place is where I talk about my personal projects, interests and whatnot. Not necessarily related to audio, although it often is. Under the Musings button you'll find things related to perception and conciousness which of course are very much applicable to audio!

My library lists lots of (historic) audio papers and studies that I personally find important to understand many different issues in audio.

I also have collected the interviews I've done with audio luminaries. Take some time to read and digest them - there are very interesting and worthwhile gems in each of them! My projects however is audio stuff - things I designed, wrote articles about, and my personal system. Comments and remarks are always welcome!

Last but surely not least, let me mention my publication Linear Audio. Published twice per year, over 200 pages of technical audio related articles from international authors. Article abstracts and author bio's can be read at the website, and some articles are available for free online.

So, take a look around, explore the various areas and let me know what you think!



Question: Autoranger BOM updates

Over the course of people building autorangers, parts values can be refined, as follows:

1. The attenuator board layout shows an SMD 'C13' at the middle front. This capacitor is not fitted at the board and does not need to be fitted.

2. In some cases, the calibration range of the capacitor trimmers is not large enough. For the -48dB calibration, it is recommended to replace capacitors C5 and C17 (22pF) with a 47pF value if available, or just short them. With the -16dB calibration, C7 and C11 (22pF) can simply be left out.

Question: Signal to Noise ratio

All specifications are available in the Spec Sheet which is part of the Data Package which can be downloaded from the Autoranger page.

Question: Does the Autoranger need calibration, and what equipment would I need for that?

There are 3 calibrations that should be performed. The correct order is first to do the level meter accuracy and common mode adjustments, and then the frequency response adjustments for single ended and balanced inputs. To perform the calibration procedure, the cover of the unit has to be removed and test signals inserted and/or measured at internal test points as indicated in the calibration procedure.

In the calibration procedure the signal generator is called upon to supply output levels up to 10V or more, at frequencies up to 100kHz. An AC RMS voltmeter is needed for various tasks: For the display accuracy calibration, the AC voltmeter should be able to measure a 1V signal at 1kHz at preferably better than 1%. For the CMRR ration a null adjustments is done, and the AC voltmeter should be able to measure down to the mV level at 1kHz. For the frequency response flatness adjustment, the AC voltmeter should have a bandwidth extending to a high frequency, preferably 100kHz. Absolute accuracy is less critical here as the measurements are relative to levels. 

For a complete description and possible workarounds see the Calibration Procedure in the Data package.


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