Where To Buy Kits For The Stereo DAC
Both Jaycar and Altronics will be supplying kits for this project and both companies will be supplying the Input and DAC Boards with the surface-mount ICs (IC3 & IC6) already soldered in place. This is a real bonus as it will save you the hassle of having to solder these small devices in by hand and risk ruining the boards.
The Jaycar kit will be in short form only and will consist of the Input, DAC and Front Panel Boards plus all on-board parts. A kit for the Power Supply Board is available separately (Cat. KC-5418).
The Altronics kit will be complete and will include all the modules, the power supply components (including the transformer) and a laser-cut custom steel case with screened lettering. The modules will not be available separately except for the Power Supply Board (Cat. K-5501) and the remote control is not included.
Jaycar ZL-3003 TOSLINK receivers were specified for this project in the parts list published last month. However, Altronics also sell TOSLINK receivers (Cat. Z-1602) which are pin-compatible with the Jaycar receivers.
The only problem is that the Jaycar units run off 5V, whereas the Altronics units require a 3V rail. As a result, we have slightly modified the PC board so that either receiver can be used. This involved fitting a 3-pin header near TOSLINK1 on the Input Board, so that a shorting jumper can be used to select between +5V and +3.3V rails (3.3V is close enough).
It’s just a matter of fitting the jumper to select the +5V rail if you are using Jaycar ZL-3003 receivers or fitting it to select 3.3V if you are using Altronics Z-1602 receivers. The two types offer equivalent performance.
Check carefully if you buy TOSLINK receivers elsewhere – not only can their supply requirements vary but they may not have the same pinouts.
As shown in the photos, our prototype DAC was built into a 1-unit high rack case with internal rails from Jaycar. However, we recommend against using this case, as the internal rails (used to secure the panels) make it difficult to mount the two main PC board assemblies. In the prototype, these boards were mounted on the rails but it really is an exercise in frustration when it comes to fitting the nuts to the mounting screws.
What’s more, once they are in and the case is fully assembled, it’s a big job to remove them again.
Another problem is the sub-panel that runs just behind the front panel. This complicates matters when it comes to mounting both the mains power switch and the Front Panel Switch Board because it means that additional cut-outs are necessary.
Finally, making sure that all the panels and rails are properly earthed is a difficult and time-consuming task.
For all those reasons, if you are not buying a complete kit, we recommend that you build your Stereo DAC into the Altronics H-5035 rack case instead. It doesn’t have internal rails or a sub-panel and so the Input and DAC Boards can be mounted on tapped spacers, making them easy to install and remove for service.