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Post by jimwilliams on Nov 12, 2014 16:13:20 GMT -6
The smaller package may stress the pcb if it's used to heat sink a surface mount regulator. Give it at least a 50% reserve or use the thru-hole style with heatsinks. Most of the power torriods have 240 primary taps. www.mcmelectronics.comwas selling power torroids for about $13. |
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Post by Johnkenn on Nov 13, 2014 21:59:00 GMT -6
YES!! (What the hell is that?) |
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Post by svart on Nov 13, 2014 22:15:28 GMT -6
YES!! (What the hell is that?) A 3D render of the ADC pcb.. didn't have much time today due to real work. Only worked on it about 30 minutes. Ordered a few power transformers for testing. I need some way of switching 120 and 240vac. I could have sworn I've seen AC inlets with a fuse drawer and 120/240 switch in one module before, but i couldn't find one today. |
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Post by jimwilliams on Nov 14, 2014 10:30:39 GMT -6
Switchcraft makes 120/240 volt slide switches, one is a panel mount for the rear of the rack, the other is a PCB mounted version for internal mounting. They are marked with the voltages and have a flat blade slot to actuate the switch. More expensive options are Corcom power inlet modules with fuse holder, voltage select and a line filter all in one, a-la Aphex.
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Post by svart on Nov 14, 2014 10:49:01 GMT -6
The TE/Corcom solution is more what I was looking for. It's more expensive as a whole, but would take less assembly and chassis modification, so usually the costs wash out.
I'm pretty sure I've seen them for fairly cheap over the years, but now that I need one..
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Post by svart on Nov 14, 2014 13:34:05 GMT -6
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Post by svart on Nov 14, 2014 15:34:12 GMT -6
OK, did a little today, started doing some of the power plane pours.  |
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Post by Johnkenn on Nov 14, 2014 15:51:51 GMT -6
So Svart, does his thing get a nickname like "RGO Speedwagon"? Actually...that's STRONG....
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Post by svart on Nov 14, 2014 16:02:01 GMT -6
So Svart, does his thing get a nickname like "RGO Speedwagon"? Actually...that's STRONG.... LOL |
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Post by jcoutu1 on Nov 14, 2014 16:02:09 GMT -6
So Svart, does his thing get a nickname like "RGO Speedwagon"? Actually...that's STRONG.... Actually got a laugh out of me with this one. |
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Post by svart on Nov 14, 2014 16:14:58 GMT -6
I think he's been saving that to use..
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Post by tonycamphd on Nov 15, 2014 9:52:37 GMT -6
that is actually brilliant! really! a name no one could forget. Reminds me of Harrison Ford Filters.
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Post by svart on Nov 18, 2014 14:32:48 GMT -6
Almost there..  |
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Post by svart on Nov 18, 2014 15:53:49 GMT -6
Going to spend a day doing DRC and visual checking. I don't want to dump 500$ into handful of boards that won't work right away..
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Post by jimwilliams on Nov 19, 2014 10:31:02 GMT -6
From experience, don't expect version 1 pcb's to be perfect. Expect to fix a few things and find a few missed things, even with DRC running. Once you assemble and run some AP tests on them you may find other issues to deal with as well.
If it's 2 layer there are some low cost proto pcb cutter machines out there that someone in the local biz probably has access too. Feed them Gerber files and they spit it out in 5 minutes. If 4 layer, forget it and pay the fab. Just don't get suckered into making more than a couple of them as they will offer more for a decent price break.
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Post by svart on Nov 19, 2014 10:46:08 GMT -6
Yeah, I used to work for a guy who wouldn't think twice about buying dozens of boards on the first spin. We'd always end up using one or two and the rest would stay packaged up while we would fix the design.
In all my years as an electrical designer, I've always had the mantra of "first time right". It's not always, but going into a design with this notion, I always attempt to get everything thought of up front and to produce a design near to the final as possible. This squashes lazyness, and usually saves a few dollars in the long run.
A few times, I've actually gotten there, but most of the time there are small changes, especially since I mainly design RF, which needs tweaking on final PCBs to account for parasitics in the PCB builds themselves.
I also typically have someone else unrelated to the project do a design review, checking power nets, offpage connectors, gerber files, running DRC again on schematic and board, etc. This has caught more than a few problems that have saved time and money.
And lastly, I typically live with the design for a few days without looking at it, and then looking at it one last time with fresh eyes. This has also caught more than a few errors.
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Post by svart on Nov 19, 2014 14:27:14 GMT -6
OK, well today is the big day. I did full DRC, added some TVS devices to the power input circuit and ordered 4 prototype boards.
I'll order parts enough for the 4, and start on the front panel board, which should only take a day or so to do, but I won't order those until I've checked out the prototype motherboards.
I'll also order a blank chassis for one prototype so I can get a feel for the physical design.
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Post by Johnkenn on Nov 19, 2014 14:33:07 GMT -6
Woohoo!
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Post by svart on Nov 19, 2014 14:51:24 GMT -6
Mind you, this is for prototypes.. The full featured product is still a ways away depending on circumstances.
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Post by tonycamphd on Nov 19, 2014 14:59:07 GMT -6
Yeah, I used to work for a guy who wouldn't think twice about buying dozens of boards on the first spin. We'd always end up using one or two and the rest would stay packaged up while we would fix the design. In all my years as an electrical designer, I've always had the mantra of "first time right". It's not always, but going into a design with this notion, I always attempt to get everything thought of up front and to produce a design near to the final as possible. This squashes lazyness, and usually saves a few dollars in the long run. A few times, I've actually gotten there, but most of the time there are small changes, especially since I mainly design RF, which needs tweaking on final PCBs to account for parasitics in the PCB builds themselves. I also typically have someone else unrelated to the project do a design review, checking power nets, offpage connectors, gerber files, running DRC again on schematic and board, etc. This has caught more than a few problems that have saved time and money. And lastly, I typically live with the design for a few days without looking at it, and then looking at it one last time with fresh eyes. This has also caught more than a few errors. you could totally substitute "mixing" under your "first time right" mantra 8) This is exciting C, it's totally fun to watch you going at this full throttle man! |
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Post by mdmitch2 on Nov 19, 2014 15:14:50 GMT -6
you could totally substitute "mixing" under your "first time right" mantra 8) This is exciting C, it's totally fun to watch you going at this full throttle man! I was thinking the exact same thing when I read it. |
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Post by wiz on Nov 19, 2014 17:11:21 GMT -6
great stuff bud
cheers
Wiz
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Post by svart on Nov 19, 2014 19:09:25 GMT -6
I got the schematic for the LCD and buttons done and the netlist loaded into the PCB layout program. I built the footprint for the LCD too, and imported the netlist. Everything looks good so a simple layout should be done and sent off in the next couple days.
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Post by svart on Nov 20, 2014 9:33:51 GMT -6
Ok, the front.. I'm just having a few made without silkscreen and without soldermask to keep development costs down, which BTW is already 600$ in boards alone.  |
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Post by svart on Nov 21, 2014 10:05:12 GMT -6
So I kinda need to start thinking about quantities. More quantities mean cheaper unit prices, but I don't want to do a pilot run of 20 and only have like 3 people buy them and be stuck with thousands of $$ worth of units.
Depending on the chassis costs, I'm looking at a target of around 300$ sales price for the ADC-to-SPDIF/AES converter.
This is around 70$ less than R-M's ADC converters.
I have subtracted the optical output as this is not industry accepted for the most part, but I have added the LCD and control system so nobody has to go inside and flip a bunch of tiny switches. Also, the units will have an expansion option for the DAC, to keep upgrade costs down. You'll open the unit, pop out a couple plastic hole covers, screw in the new board and be done(that's the plan anyway). This will keep you from having to buy a separate converter box like R-M has you do.
So should I start another thread asking about interested parties, or just have them sound off in this thread?
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