This page describes a digitally controled HighEnd preamp with the Texas Instruments PGA2311 volume control.
It will be published in the electronics magazine Elektor in all four main issues ( Germany, France, the Nederlands, United Kingdom) in two parts in April and May. It may be also published in some licensed issues, but I don't have any information about it. If you happen to have one of these issues, please take a look at the bottom of this page.
If you have any idea what functionality might be included into the software, please send me an eMail. New versions of the software will be published on this page.

For those who do not want to program a controller on their own, I offer a small amount of programmed and tested controllers.
Take a look here. Information about complete kits, PCBs, housing and knobs can also be found here.

Software versions:
V1.0 Initial version as published in Elektor - preamp_v1.0.hex (42 KB)

V1.1 Improved RC5-recognition (detects the rising and falling edges instead of applying a fixed time pattern. This will also work with remote controls which have about 30% longer or shorter signals.)
Volume change speedup. When you press the button for about two seconds, the speed of the volume change will increase. This works with the remote control also.
preamp_v1.1.hex (45 KB) - (sourcecode 96 KB)

Schematics and layouts (PDF) can be downloaded here: (1.37 MB)
This zip-file contains my original layouts, which are technically identical to the ones published in Elektor (OK, the ones in Elektor do look a lot better than mine ...). If you are going to print the layouts (they are already mirrored and added as pdf) make sure not to scale them. The Adobe-Reader tends to do so (skrink large pages, scale to fit etc.).

The PCB layouts are made with the commercial version of EAGLE, but are editable with the freewareversion. The Elektor layout is based on them, so they look quite similar (and are identical). They can be downloaded here: (147 KB)

I will add a brief description of the project (boards, wiring, functions etc.) for all the people who don't have the Elektor article in the next few days.

Here are some pictures taken by me and at the Elektor. Click to enlarge.
remotecontrol remotecontrol
remotecontrol remotecontrol

I will try to keep a list of people who build a preamp on their own. If you like to be on this list, please send me your name and your country. Additional information like URL of your Homepage and picture of your preamp will also be put on the list.

Of course I would like know, where my article is published. If you are able to send me a scan of the complete article from an issue, which is not mentioned in the list below, I will send you as appreciation of your effort a remote control for the preamp. If you plan to do so, please send me an eMail, so I can tell you wheter I already have the article or not.

List of articles I possess: