Gurkenblog

I wasn’t sure how the stands would turn out, but I think the result is pretty good for a first attempt. The naked MDF is now covered with birchwood veneer and treated with a wax coating. Now I want to get a microphone and put the DSP to proper use, although I think I need to get my ears tuned first, there’s a definite lack of bass response on the right channel. At some point, I should probably start on the preamp case (yeah, it’s still running the wooden monstrosity)…

So… while things are still well beyond the borders of prototype-land, at least this version looks a bit better than the first working version. I think it’s the metal panel that makes the difference, and the VFD.
The display can be connected via serial or parallel, I opted to use the hardware SPI interface on the Atmel since I’m not sure what I’ll be needing the other IO ports for (inputs? Serial connector? USB?). The PGA2311 and the relay latch driver are also controlled via SPI, but are activated via separate CS lines. Refreshing the display isn’t exactly fast, but does offer at least some rudimentary drawing functions such as “fill area”, “invert area”, and can be used in full graphics mode as well. My initial menu uses pretty much each feature once, including dimming the display after a few seconds.
I’ll have to keep an eye on the power regulators’ temperature, since the VFD supposedly draws ~400mA, which is more than the entire rest of the preamp. They are mounted on the underside of the PCB and attached to an aluminium panel, so that should dissipate enough heat (later, they will be bolted to the 3mm case bottom).