Prototype Profile

The Schroff extrusions and side plates arrived this morning about a week after I placed the order. Well done ForeMost Electronics for thrashing the 2 to 3 weeks estimated delivery.  I spent the afternoon sketching possible mixer profiles. I know I want a 9U main sloping panel at an angle of around 35 degrees. I know I need 4U horizontally in front of this for the fader nose and it needs to be deep enough to leave room at the back for a 3U space for bus amplifiers and the like. Apart from that, the overall shape can be anything I fancy. I also know the fader nose has to be about 200mm high so that the main 9U space can sit at 35 degrees. If it is anything less than this then the slope rapidly increases and we end up with a profile like the 500 pictured in the previous post.

The piece of wood I have is 1800mm by 450mm so the biggest profile I could do would be 900mm deep and 450mm high. I did a profile in wood some time ago using wood that was only 340mm high and 800mm deep. I laid out the Schroff end plates on this to see if they could be made to fit. As the piece of wood is only 340mm high the 9U space ends up at a rather shallow angle but the profile looks quite promising:

The 4U fader nose is on the right. This is a standard Schroff 4U paenl which is 175mm deep. As you can see, the bottom corner of the sloping 9U section is very close to the bottom of the wood. I laid a Eurocard PCB with the 32 way connector in the bottom part of this 9U space and you can see that by the time the mating half of the connector and the motherboard have been added there would be no room to run the cables from the fader nose to the motherboard. There is room at the rear (bottom left) for a 3U section for the bus amps etc. and possibly room for another at the top or at least a 3U high space to fit all the connectors. There is not really any more space in this profile than there is in the Rackz enclosure I am using for the EZTubeMixer demo and that one is far too cramped for easy wiring assembly. So, although this profile is possible. it does have some drawbacks.

I then realised that 9U is a fraction over 400mm and the new piece of wood I have is 450mm high. This means it would be possible to fit a 9U side plate at the rear of the mixer. The bottom 3U could be used for bus amps etc. and the top 6U could be divided into two more 3U spaces for input and output connectors. Furthermore, this 9U could be placed so there was a 25mm gap below and above it. Those two 25mm spaces could be used to fit wooden bottom and top pieces. The fader nose would now be 25mm higher making it a total of 200mm which is what we need for the 35 degree slope. So I drew this out on paper several times and concluded that it would still fit nicely into a depth of 800mm. Although the wood I have could make a 900mm deep profile I felt this was too close to the 1000mm width of the mixer. 800mm would make it look more rectangular. Here is the result:

The slightly greater angle means there is now plenty of room for the wiring from the fader nose and there is a lot more room between the main 9U sloping space and the rear mounted bus amps which should make wiring a lot easier. There is also plenty of space on the rear for connectors. The flat top towards the rear is just over 300mm deep - just big enough to lay a near field monitor on top.

The next step is to fix the side plates to the wood and attach the extrusions to make the basic framework of the mixer.