Thrax Audio introduction & Tech pt.5

When do people use the expression: “Greater than the sum of its parts” ?

It seems like they had the Dionysos in mind. Implementing all the ideas described before into a manageable product required some real thinking.

Input transformer with relays selecting the inputs, relays selecting the transfer ratio, relays selecting passive active, relays selecting amplifier gain, relays selecting ground points and output type…..that is a lot of relays!! Relays selecting power and stand by and then buttons , rotary encoder and displays …. Well you get the point. If we think vintage that would be another box for the control logic only but lucky us, the industry has developed programmable micro controllers capable of handling all this and much more with considerably useful development tools. A task way beyond the wildest dreams of any experienced vacuum tube electronics designer. (excluding the ones developing tube computers).

Yes this required a totally different skill set and opened up an opportunity beyond the reach of many other designers. We can program logic, we can add functions, we can memorize settings like in the most advanced home theater setups. Here is where user experience had to come in handy - luckily we had plenty of that and here is what we decided to do:

We left it to the user to select if each RCA input or output should share ground plane with the Dionysos or if it should be left floating. We also decided to have RCA and XLR outputs that are user selectable and as those controls are not to be changed daily we left them on the back. Then we let the user select the absolute phase for each input. Some sources invert the signal, others don’t, and some people are sensitive to absolute phase, so we even added this function to the remote control. Oooh remote control… that is new to most tube amplifiers.

As the volume control and passive / active switching required a complex algorithm for controlling the corresponding sets of relays we decided to use a rotary encoder to give the feeling for a regular potentiometer while changing relay status accordingly. But rotary encoders are endless, so to know where you are and be able to go to a particular volume setting a display was needed telling you the selected level. Ok but you have two channels and if you engage the balance function you need to know the setting of each one...hence two displays for the two attenuators. When designers say form follows function they mean it. Packaging all this in a box and making it stand out from the crowd - creating Dionysos' own unique look was a task given to local award wining architect Atanas Panov. Well maybe he initiated it by saying: “Who did that, I am not putting that in my home, here is what we will do….” and he did, his emblematic design is timeless.

To serve some Yankees we decided to add the extra function of Home Theater integration fixing the volume on a selected input enabling the use of your high end stereo system as front speakers whit no degradation when listening to music. One of the benefits of using a microprocessor – you can add functions that you did not know you needed. Like as often people don’t realize how quickly time passes, we build in a timer counting the hours of tube usage and reminding them to have a look and get those replaced before a noticeable sonic degradation appears.

I guess this is enough to have you pick up the phone and ask you local dealer for a Thrax Dionysos demo. The design keeps evolving but it retains the same structure now with Mk2 coming up.

Next one will be for our second product The Spartacus power amplifier!