Author Archives: remco

Writing 24LCxxx EEPROMs with PICkit3

Since it took me about 8 hours to fetch all the information together and get it running, maybe this post will be useful for other loonies like me who think this is a good idea šŸ™‚

You see, the Microchip PICkit3 seems like a steal – a cheap, full featured PIC programmer that can also write EEPROMs!

Well, they weren’t lying. Then again, it’s not exactly the truth either. Continue reading

Arduino software control for WM8804/WM8805

WM8804 application board (eBay) modified to output CLKOUT pin (yellow-black wire)

Recently I needed a special type of I2S signal, namely a 4 signal set of DATA, BCLK, FCLK and also an MCLK of 49.152 MHz.

Many modern DACs, DSPs and digital power amplifiers need this high clock frequency. And of course you would want this signal to be synchronous to the Frame Clock such that the converter has a fixed number of MCLK per FCLK cycles so as to minimize jitter.

Many S/PDIF receivers implement a fixed clocking in hardware mode which limits your options and flexibility, so it is worth exploring software control. It is really not so hard. Continue reading

Measuring USB devices with an Audio Precision System One or Two

There is one thing the older Audio Precision System One and Twos don’t have which can be quite annoying: they don’t have USB host functionality. And given that all the processing and clocking happens inside the unit, the control software can’t reroute the digital signal generator to a USB output.

Tenor T7022, an often-encountered USB receiver. Does it do bit correct feed-through?

Of course you can use a PC to feedĀ the USB sound card and measure the output with the AP, but then you don’t have the generator signal to do e.g. sweeps or automation. The best of courseĀ would beĀ to somehow get to a full loop starting at the AP signal generator back to the analyzer. After quite a lot of tinkering, I managed to do just that.

Continue reading

And now, for some music

Surely, you can’t have missed that Linn are giving away a bunch of 24 bit tracks at the end of the year?

Last year, I had to log in every day and still managed to miss a few days, luckily some buddies helped out and we got the collection complete.

This year, they’ve been extra generous and left the whole collection up for grabs until January 6th. So in thanking them I’ll happily plug the Linn site for all my readers (yes, both of you).

Linn Records – 24 bits of Christmas

As the year draws to a close and we prepare for many changes in 2015, I’ll plug in the same wm8741 that Linn use in the Klimax and enjoy the recordings. I’m not a big classic fan, but some of the recordings in this collection are absolutely breathtaking. Well either that or I’m getting older.

Enjoy and see you in 2015, which is shaping up to be a pretty exciting year!

AKM AK4393

The following measurements were taken with an M-audio Delta 1010 sound card, using channels 7 and 8. These cards have an AKM AK4393 D/A converter. The M-audio has an otherwise fault-free design and is a great converter for the price.

Input was S/PDIF, output balanced -4 dBV.

I’m dropping the raw measurements here with little comments as long as the results are in line with what you’d expect from a device like this, since I’m mostly interested in the IMD measurements, after the last postContinue reading

WM8741 vs. ESS9023

I’ve been looking at designing a D/A converter for a while now. In my experience these are some of the hardest audio components to do right. It started with building output stages over a decade ago and at some point I even found myself in a company designing a D/A converter transistor by transistor.

However, as recent experiments have shown, I still have a lot to learn.

Continue reading

ESStech gets it. Well, almost.

Recently the ESS Technologies products caught my attention (keep an eye out for some measurements shortly).

Just today I stumbled upon a presentation called ‘Digital vs. Analog Volume Controls‘ which is interesting in light of my opinion written some months ago, ‘The Case for Digital Volume Control‘.

Although probably written with a strong marketing purpose, a number of observations make me think there are some gaps in mixed-signal architecture thinking that deserve attention. Continue reading