Future Projects

In this section I am noting down some ideas I have for future projects given time to complete them, and as you can see I have other interests too!

The project I am roughly halfway now is to build a pre amplifier that accepts digital audio signals from minimal three optical and/or coax S/PDIF sources  and supports up to three analog inputs, one being a low noise phono input. Outputs are analog  and optical SPDIF out.

Several ideas were playing in my head to control this pre-amp.
One thought was to incorporate a simple webserver and WiFi connection so that my Windows Media Center PC can connect via its browser to the pre amp and control input channel selections, volume and balance. I consider tone controls not nessesary. A smartphone can also be used for control.

This is much sexier than yet another remote control.
Tured out that will be a significant software excersise so I looked for a simpler way to control the pre-amp.

Logitech now has a neat remote called "Smart Control".
It consists of a programmable IR remote plus a hub that supports many other remotes from devices like my cable TV box, TV and also the Arcam A65 pre-amp. The Arcam remote simply generates RC5 IR commands that are relatively easy to interpret by an IR receiver in my pre-amp..
The Logitech hub receives IR commands from the universal remote and sends them off through cables with an IR transmitter at the end that you stick on top of the IR receiver of your multimedia box, amplifier and what else that is behind the doors of the gizmo cabinet.
The Logitech hub also has a WiFi interface that hooks up to your local network and with an app that you can download on your smartphone or tablet you can also control all devices.
This gives actually three advantages.

1: Only one remote and/or tablet for all my equipment

2: Control via tablet or a single universal remote 

3: A simple IR receiver design in the pre-amp.


I finished the breadboard design of the phono pre-amp, that will be switchable between moving magnet and moving coil elemants.
It is built completely discrete with a differential JFET input stage (2SK369). By adding more differential input stages in parallel the noise of the phono amp can further be reduced but 82dB SNR @ 5mV input signal proved to be quite sufficient in listning tests.


Another project in the early thinking process is an upgrade of my FireWire AFE test box.
I have found a soundcard that supports 192KHz 24bit audio I/O over coax S/PDIF as PC interface.
This is the ESI Juli@XTe (http://www.esi-audio.com/products/juliaxte).

There are also ASIO drivers available that my audio measurement PC software supports
The SRC4392 supports these data speeds and at the I2S side of the device I can down sample the signal to the desired speed and I2S settings.
Analog I/O is now under my own control and no longer at the Behringer box with its limitations and I can even add a direct I2S I/O capability to get almost the functionality of an Audio Precision system when hooked up to the PC running the Audiotester software (www.audiotester.de)