Sligolad wrote: ↑Wed Nov 21, 2018 10:50 pm
Of the 3 choices the first one would be best due to the depth being 280mm, the others are shorter in depth so they would not work.
If we could find one 200 to 300mm wide and at least 280mm deep we should be OK.
Height needs to be at least 70mm.
The finned cases might be a bit thick for machining the USB hole and the SD slot.
Will have a look as well.
After looking at all the options it looks like your first choice is best Nige.
As you say we could cut a chunk out and fill with a print, should be easily doable though we would need someone with a milling machine to cut the slot for the print.
id be confident i could cut them with a grinder with stainless disc
We could probably get away with the case Derek picked but the panels are very light and we would need to reorganize the layout inside to make better use of the added width. Will take a look tomorrow.
sd card player, modded soekris dac, class a lifepo4 amp or gb class a/b amp, diy open baffle speakers based on project audio mundorf trio 10's
Thinking through it a bit more I can print a facia with the SD slot in it which can then be bolted onto the front of the case.
All we would need to cut then is a USB hole.
I have most of the printing ready for the prototype, the front fascia I should finish later tonight and the Lid I will run tonight.
The front fascia will house the standalone SD Card and allow access to the SD card in the fascia unit.
I might be a little late if the Lid is close to finished in the morning I will wait on it, I assume we are still on for tomorrow?
We have plenty of options on power and even 3 of the big HPULN supplies will fit where the Supercaps cradle is with ease...for anyone wanting to spend serious money on power supplies :-) https://www.mpaudio.net/
In the pictures I have the 5 Reg board in there and a larger USB card, could not find a smaller one.
I put the back and front of the SD Player unit on the case to show the fit and option to use the parts from the SD Player unit.
RE the slot for the USB - what would be easy to machine on the case would be a circular hole (I could do that here easily on my manual milling machine - so if going with something there, a printed insert to match the hole would be a good way to tackle it. Wouldn't need to be big and so wouldn't take much time to print. Thinking further after seeing the 3D printed case today, I really like the slope on the front, I think it makes the card player much more user-friendly.
The other item I though was fantastic was the supercap holder. It looked top notch, and very useful for holding them.
Testing out a circuit for a relay to switch in the supercaps after the regs. Seems to work, although a bit more work needed now to finesse it, and to allow for adjustment. The idea is that at turn on, the dac is powered by the standard supply. The supercaps charge (which may take upto a minute or so). When they reach full voltage, the relay switches and feeds a supply after the on-board regs - which should sound better. When the power is cut, and the voltage at the super caps starts to drop, the relay clicks out.
