Interest in a general purpose reg also 6.3v DC from 6.3v AC?

Andrew · Post by **Andrew** » Thu Mar 27, 2014 8:14 pm

I'm thinking of using the some of the basic design ideas of the heater regs I've done as the springboard to do a general purpose reg PCB for the linear style reg chips. This would include low forward drop diodes, low ESR caps, high quality 3 pin reg such a LD1085, diode protection, output caps, wide range of voltage set resistors and the potential for split rail operation, on board heatsink, basically the works and hopefully 6.3v DC from 6.3v AC! There's no fancy second stage as on the heater supplies just an all purpose PCB to house your favourite programmable 3-legged reg chip.

Same PCB quality and kits as before based upon a group buy process, I need this PCB for a DAC I'm working on as well as supplies for a long tail pair current source etc, so I'm happy to share, is anyone interested?

thanks,

Andrew

little eddy · Post by **little eddy** » Thu Mar 27, 2014 9:10 pm

I guess you're looking at a modest current rating if a DAC is your intended application?

Andrew · Post by **Andrew** » Thu Mar 27, 2014 9:11 pm

No, should be good for anything up to a couple of amps, of course bung on a smaller heatsink, or none at all, and it should be fine for a DAC.

cheers,

Andrew

Ray P · Post by **Ray P** » Fri Mar 28, 2014 5:59 am

Could be interested Andrew.

What would be really useful (and, with hindsight, might have been a good option on your previous PS boards) would be to make them complete standalone units. For use up to a certain rating (say for use in DACs, preamps etc.) could you add a section to the board to accommodate a standard series encapsulated toroid transformer and maybe a fuse - that would be really neat, compact and flexible. The section could be removed for higher current use, either by scoring to snap it off or just let people get their hacksaws out. It will only make a small increase in the cost of each board.

Ray

Andrew · Post by **Andrew** » Fri Mar 28, 2014 8:27 am

Its a reasonable idea Ray but the problem is that there's quite a wide range of transformer sizes e.g. http://www.rapidonline.com/pdf/525383.pdf . For that reason an off board transformer makes more sense as it allows more flexibility.

If there's enough demand I can do two PCB, one high current and one low with a PCB mount TX, but there has to be enough demand. to cover the costs.

Andrew

Ray P · Post by **Ray P** » Fri Mar 28, 2014 6:23 pm

I was thinking along the lines of these;

http://www.digikey.co.uk/scripts/DkSear ... 7293889911

Should be easy to put a couple of different footprints to cater for various ratings and if the section of the board is removable you only need one PCB.

Ray

Andrew · Post by **Andrew** » Sun Mar 30, 2014 12:11 pm

Hi Ray,

Link doesn't work

Andrew

Andrew · Post by **Andrew** » Sat May 03, 2014 9:57 am

Here's the generalPCB layout, its a variable reg PCB that can be used in grounded or center tap mode, so pretty general purpose, it should be good for the max current rating on the reg assuming not too much voltage drop and the heatsink is up to it, I have left plenty of space for a big heatsink; you simply load different components depending upon the configuration you want.

Andrew

Ray P · Post by **Ray P** » Sat May 03, 2014 1:57 pm

Andrew, this is the sort of thing I had in mind when I talked about the transformers being an on-board option; check out the opening post.

http://www.diyaudio.com/forums/group-bu ... oards.html

Ray

Andrew · Post by **Andrew** » Sat May 03, 2014 3:28 pm

I see what you mean Ray, but by doing that you severely limit the board's appeal as you can only really design for one size and make of PCB transformer. I took a look at the PCB mount transformers and they vary in size quite a bit depending upon what you VA and voltages you want. By fixing the voltage and VA you can't then use the same board at other current /voltage values; this stuff needs some volume to make the PCBs cost effective, a small toroid therefore seems the best solution.

Andrew

Ray P · Post by **Ray P** » Sat May 03, 2014 8:36 pm

Fair enough Andrew, though those boards are designed to use with the onboard transformer or an off-board one for higher current requirements.

BTW, I crept under the wire in signing up to that group buy; for the prices it seemed too good to pass by on a good but cheap I2S DAC and power supply to build a headphone amp/streamer around.

Ray

Post by **Nick** » Sat May 03, 2014 9:43 pm

Ray P wrote:Fair enough Andrew, though those boards are designed to use with the onboard transformer or an off-board one for higher current requirements.

Yep, but PCB's are costed on area. those boards have half the PCB taken up with the transformer, so adding the transformer and not using the space will double the cost for thsoe that dont want or need it.

Ray P · Post by **Ray P** » Sun May 04, 2014 9:34 am

Nick wrote:
Ray P wrote:Fair enough Andrew, though those boards are designed to use with the onboard transformer or an off-board one for higher current requirements.
Yep, but PCB's are costed on area. those boards have half the PCB taken up with the transformer, so adding the transformer and not using the space will double the cost for thsoe that dont want or need it.

Yes, having recently had some PCBs manufactured, I know area is a cost driver,though the largest cost for something like this limited run is the initial 'tooling' set up so the price differential won't be that great.

As I recall. the projected cost of the power supply PCBs on the group buy I linked to was 4Euros if there was demand for 50 of them; that's £3.30 for a board for three regulated supplies (1 * +/-12V and 1 * 6V ) and space for two transformers; the board area for the transformers is clearly not costing very much.

Anyway, it was only a suggestion and it's Andrew's project and design parameters so that's cool.

Ray

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Interest in a general purpose reg also 6.3v DC from 6.3v AC?

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