Pimeta mounting/casing.

I see only one actual question above. The answer to it is "no". :)

That is based on the expectation that this will be put in a metal box, and that you will be tying the chassis to virtual ground through the pot chassis and input jacks. DC input and output jacks will be isolated from the case. All of this is laid out in the docs.

Quote:

Originally Posted by epithet 

Is supporting the Pimeta solely by the volume knob mechanically safe, viable, sufficient, etc?

I've done that many times with boards similar in size to the PIMETA, and smaller. I have yet to shear a pot off at the mounting surface, or hear of anyone else who has.

The larger the board gets, the more I'd be happier with some additional support. I've never made a PPA that had the board solely supported by the pot, for instance.

I would guess that mounting the board by the pot alone is enough for applications as strenuous as daily jogging. If the amp is subject to more stress than that, you may need to use the mounting holes and stand-offs.

Given your "professional audio rack" application, I'd say the biggest risk would be with portable musicians' racks. Drive it all around the country in a van with a stiff suspension, have a roadie drop the case out the back of the van a few times a year while unloading, roll it across asphalt and sidewalk cracks twice a night, and I wouldn't like to give better than even money of such an amp surviving more than a few years.

For a board the size of the PIMETA, you're probably at greater risk of snapping electrolytic caps off the board before you break the pot, though. I have a friend who works in electronics test, and he tells me this actually happens in shaker table tests! This is why you sometimes see a glue of some sort around the base of taller electrolytics in commercial gear. For the most part, this is a form of extra UPS shipping insurance.

My road musician scenario is like sending the amp via UPS every gig night. 

If this truly worries you, you could make a pair of mounting brackets from aluminum bar stock. One 90 degree bend and three holes per, plus 4 standoffs, and you should have something fairly bombproof. It means two more screws on your front panel, but what price peace of mind?

The second biggest risk of mechanical damage would be the solder joints on the hookup wiring. If you're doing something like my road musician scenario, I'd zip tie each wire bundle down to something solid.

There are 1U rack boxes out there. That would make it effectively RF-impervious, over the frequency range a PIMETA v2 will respond to.

If you decide you still want to go with your original idea, it's probably fine. There are a whole lot of plastic and wood-encased PIMETAs and similar in the world. We're not seeing a whole lot of complaints about them.

A particular worry in your case is audio crosstalk among close-packed equipment. I'd recommend using shielded cables to minimize the risk.

Quote:

Originally Posted by epithet 

Did you happen to see and would you be interested in making any suggestions for me on this thread re: balanced inputs? http://www.head-fi.org/t/576443/balanced-inputs-for-likes-of-pimeta-amplifier

What you see in the docs is as close to a brain-dump as you're going to get from me. That's all I have to say on the topic. It is, veritably, the alpha to omega of my vaaahst experience in the field of balanced audio.

Look at the scratchpad docs. You will find several extra pads in there with supply voltages, one for each major supply voltage node, and a few extra grounds,