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Art For Engineers


Well mandala-1we all like and enjoy beautiful things of life. Art is a fine example. Engineers however are a kind of  different animals. They enjoy looking at bizarre things. I do as well. What you see on the right is a fine example. A “painting” made out of electronic elements. Almost every possible type of electronic device is used and I think it’s amazing.

No deep thoughts about this. I’m not an art expert. Some might find it ugly, some might find it strange or whatever. I just wanted to share this with everybody.

If you like this be sure to check out this website.






DIY USB Isolator Made Easy

Are you into high quality PC audio? Do you have one of these nice USB DAC’s that pull all the good musical stuff out of your computer? Then you might need to check this article out. You can vary well improve your USB DAC performance by isolating it from all the garbage coming from the noisy(electronically) PC.

What I’m about to show in this article is a way to build you own USB isolator and improve your USB audio. The isolator itsel is build around the ADUM4160 chip from Analog Devices. The complete datasheet is here:

Since the schematic for this project is rather simple, a single layer printed circuit board can be made. Of course a double layer is always better option.

This is how the whole thing looks:

The project also makes use of one high quality LDO regulator. In this case I’m using Linear Technology’s LT1763 fixed voltage (5V). I’ve used this one before in some other projects and I’m quite happy with it. The datasheet is available here:

The board allows you to use external regulated PSU just in case you don’t trust the LT’s chip. This is the complete schematic for this project:

The circuit is pretty straightforward but here is some explanation. JP1 switches the speed – open=low speed(1.5Mbps), close=full speed(12Mbps).

JP2 function is explained here:
The ADuM4160 has an option to delay application of the upstream pull-up under control of the peripheral. This function is controlled by the PIN input. In this application, the PIN input is jumpered high so that the upstream pull-up is applied as soon as peripheral power is applied. In other applications, it can be connected to a GPIO pin of a controller, a fixed delay circuit can be applied, or it can be connected as shown in this circuit. It is the designer’s choice how to use this functionality.

I personally use id closed. JP3 allows you to switch between the power supplies of the second half of the isolator. I recommend using the build in regulator. In this case the board need 10-15VDC. A simple DC adapter will do the job.

The PCB artwork in 1:1 scale pdf file and component placement is available for download HERE.

The PCB can be easily made using a laser printer and an iron. I encourage you to try this simple upgrade, as you won’t be disappointed.

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Low Jitter Clock For CD Player – Upgrade Module

Do you have one of those expensive CD players that use a simple quartz oscillator to provide the clock? Anyways, the clock upgrade is no doubt the most important upgrade to any CD player. Otherwise you will never hear that nice smooth analog like sounding from your gear.

What you need is a low phase noise clock source to feed the CD player.
Searching the web will come out with many ways to upgrade your CD player. Some of those upgrades come at substantial costs. Many sources simply don’t provide enough data to prove those high costs in my opinion.

So i searched and searched for a nice clock project to upgrade mu trusty Arcam Alpha 5 CD player. This one was already upgraded with a nice new TDA1541A S1 DAC chip so I was impatient to reveal its true potential.

So finally I came across a nice article about The Flea Clock from Pink Fish Media. An very interesting project indeed. What that project aims at is in reality an ultra low noise PSU to power up a Tent Labs oscillator. So my project was based on that one from PFM forum.

I just had to change some things to fit my personal needs.
First – the oscillator was unable to drive any substantial capacitive loads, so I needed to buffer the outputs. Buffering is an easy task. A simple inverter would do the job. In this project I’m using two 74VCH1G04 ic’s to provide me two outputs.
Second – i wanted a oscillator with real measured parameters showing the phase noise and jitter performance since I had no way(equipment) to measure the jitter myself. Few manufacturers that in My opinion are suitable for the task:

Fox Electronics HC-73 series oscillators:

EuroQuartz XO-91 series oscillators:

Silicon Labs Si510 series oscillators:

In my case I’m using 11.2896MHz oscillator to feed the digital filter’s XIN pin(pin 11 on SAA7220 chip). This is the most basic way to feed the new clock to your CD player. Simply remove the quartz form the player and the two caps and the resistor. Here is how I did it:

 A more advanced reclocking to your player can done using a flip-flop to reclock the I2S bus before fitting it to the TDA1541A chip. Here is how its done:
This method has one major disadvantage. It uses one IC to process all three wires of the I2S bus. A better way is to use three IC’s but it’s cost and space consuming.
Possibly the best way is to feed the clock separately to the digital filter(SAA7220) and the DAC chip (TDA1541A). The DAC chip itself requires half the frequency provided to the digital filter. So we need to divide the clock coming from the module. This can be done again using a flip-flop:
In my opinion this is the better sounding reclock. Anyways, a wide field for experiments is available.
So this is the final result. Here is the clock module PCB fitted into my Arcam Alpha 5 CD player
Ultra low jitter clock fitted into Arcam Alpha 5 CD player
The module itself is powered by a preregulated PSU using a LM317 vreg providing 18VDC. I’m using a small transformer to power the whole thing up. This is the better way to do it. One can still use the already available supply rails from the CD player but 18VDC is the minimum voltage required in order the module to work.
A complete schematic for this module is available HERE.
WARNING – This design is provided to the DIY community for free and is intended for personal use only. Therefore the commercial usage is NOT allowed.
*************THANK YOU FOR READING THIS ARTICLE**************

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