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Remote trigger, momentary switch, soft start PCB (for First Watt or other projects)

Dear all,

With 2 friends we finally started on our Aleph J endeavour. The only thing missing was a PCB for remote trigger and momentary switch functions. So I designed one. I also included the same soft-start circuit as the boards in the Diyaudio store (on a separate panel). We're planning on making some PCB's and were wondering if there is any interest to justify a group buy.

Here a list with the features:

-Regulated power supply (you can make it both in 12v and 5v versions)
-DC out (in case you would need low voltage DC for something else)
-Remote trigger in (on board Neutrik NRJ4HF jack connector)
-Remote trigger out (on board Neutrik NRJ4HF jack connector)
-Flip flop circuit for momentary (push button) switch
-Master/slave selection jumper: When on 'master', the push button triggers the remote out. When on 'slave' a 'remote in' signal will trigger the remote out.
-Soft Start circuit on separate panel (you can directly jumper the connections from the trigger panel)

The circuit:
Relay Triggered Soft Start.png

The silk screen:
Relay Triggered Soft Start Silk.png

The top layer:
Relay Triggered Soft Start Top.png

The bottom layer:
Relay Triggered Soft Start Bottom.png

And the BOM:

https://docs.google.com/spreadsheets/d/1wuRiQT88Ayec_TbUO5dYTE26nykChvB25nKcq-sWmrU/edit?usp=sharing

With 2oz copper and the current track width of the mains voltage tracks, the PCB is rated for a little over 5 amps. So this is more than enough for most First Watt power amp projects. You can of course also use it to trigger any other device of choice (you can break away the soft start panel).

Because of the design and the internal organisation and layout of our case design, it's quite a tight layout with specific size constraints. It however is compatible with the Diyaudio universal mounting specs (mounting holes are all distanced multiples of 10mm from each other).

We we're thinking of the following PCB specs:
-2mm PCB
-Black soldermask with white silkscreen
-2oz copper (if there is an overwhelming need for high current ratings, we could also go for 3oz, but this makes it ~30% more expensive)
-Immersion gold finish

Depending on demand the price will be around € 10,- for a single PCB. (Excluding shipping. Price for >20 PCB's total)

Any comments are of course welcome. I will of course change the design if you guys find errors both in the circuit or layout. But I was not planning on including any more functionalities (also because of the size constraints).

Reply with your name and the number PCB's if you want to join.

Cheers,

Maarten
 
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I would be interested in at least 2 boards if they were able to work with 120V mains.

Hi Dan, there is room on the board for Hammond 162F transformers (available at Mouser), these have dual primaries. So you can jumper J1A with J1AB and J2A with J2B for 115V/120V operation. The other type of transformer that fits are the Block 3,2VA (available at Newark, e.g. AVB 3,2/2/15). But the board now has only pads for single primaries for these Block transformers (and those are not available from Block for 115V operation). I will see if I can change the layout if you want to use those.
 
Update:

-Included option for dual primary 3.2VA Block transformers.
-Corrected primary wiring of Hammond transformer (I got confused by the figures in the datasheet).
-Cleaned op the silkscreen of the transformers
-Measured power consumption: driving 2 relays the remote trigger circuit and flip/flop circuit consumes about 0,25W. The standby consumption is negligible. So most power consumption will come from the transformer losses. The no load losses of the Block transformers are 0,6W (single primary) to 1W (dual primary).

Relay Triggered Soft Start_1.png
Relay Triggered Soft Start Bottom1.png
Relay Triggered Soft Start Top1.png
Relay Triggered Soft Start Silk1.png
 
I would be interested to take a few boards if you would make it to work up to 10A-15A

Thanks
Do

Hey Do, 10A would be possible if we go for 3oz copper boards. I would like to comply with IPC9592 standards as it is a power circuit. For 230v (here in the Netherlands) this means a minimum trace spacing of 1.75mm. I took a quick look (I would have to check exactly later on), but I could widen the tracks with 1,2mm and stay within the IPC9592 standards for 230V operation. As the circuit has to operate in a hot environment, an acceptable temperature rise would be 25C. This results in a current rating of 11A (IPC2221 standard). If you make it a well ventilated environment you could also probably go for 30C, then you can go up to 12A.

You would however need to use the Omron G5LE-1-E versions (the high capacity rated G5LE), to switch currents >10A. These are still available. An even better option (and highly recommended if your currents are truly >10A), would be to use a panel mounted solid state relay. For example, Mouser part 653-G3A-225B-DC5.

With current interest (10 boards for me an my friends), 2 boards for Dan (if he still is interested if the boards are more expensive), and say 2-3 boards for you, that makes an order of 15 boards. With 3oz copper this brings the board price up to € 20,- per board (compared to € 16,- for 2oz)(this includes shipping from China to me, but not shipping to Canada). If we can get interest up to 20 boards, the price would be € 16,- / board. If 8-9 amps is enough (see my comment below), we can stick with 2oz copper and that would mean considerable savings.

So from my point of view: I would be willing to pay the premium if Dan (and maybe others) is willing as well. Otherwise it really comes down to who of you wants the most boards, or if you are willing to pay the difference.

I don't know how much wattage you need to switch, but with 115V mains and 9 amps the board is rated over 1kW. Of course you want some headroom, but I don't know many projects that need that kind of switching power.

Let me know what you think.

Maarten
 
I have a few Zero Crossing 40A SSR at home but with some transformers it makes them hum badly... Replace with a simple mechanical relay and hum is gone! I don't know why I have this issue but it is not a single toroid transformer but different model/brands.

I would definitely try 2 softstart. To me 4 euros difference per board is nothing but if its a no go for everyone else then we can go for the 2oz copper, still I prefer higher switching load.

Ciao!
Do
 
I have a few Zero Crossing 40A SSR at home but with some transformers it makes them hum badly... Replace with a simple mechanical relay and hum is gone! I don't know why I have this issue but it is not a single toroid transformer but different model/brands.
I believe you should only use the zero-crossing SSRs with resistive loads and that might be the reason the transformers hum. Lots of useful information regarding SSRs in this document http://www.omron.com/ecb/products/pdf/precautions_ssr.pdf which I also used for my own published designs.

/U.
 
What is the size of pcb ? I think i'm interested in one pcb. IS not clear for me what is the function of Remote trigger in/out.
The total PCB size is 162mm X 80mm. The trigger panel is 99mm X 80mm and the soft start panel is 63mm X 80mm.

The remote trigger in you can use to switch (trigger) the relay on the trigger panel with a DC voltage from for example a pre-amp or receiver or DAC with a trigger output. So to switch it on automatically when you turn on another device.

The trigger out will generate such a DC voltage (12v or 5v, depending on your choice) to switch on another device with a trigger input. Depending on how you place a jumper on this board, the remote out will either be triggered by a remote trigger in signal (slave function) or when you switch the board on using a momentary switch (master function).

Sent from my SM-G900F using Tapatalk
 
I widened the tracks to 4.2mm, so 12A is a feasible option.

Current interest:

Mfly: 10
danbmellow: 2?
pinocchio: ?
atupi: 1?
herb1diaz: 4
jormajj: 2
Bones13: 4

So for now we are looking at an order of ~25 boards. With 3oz copper this brings the board price to around € 14,- per board, excluding shipping to you.

Could people with a question mark behind their name fill in the amount of boards they want?

I think I'll wait for another week or so to see if there's more interest and then start the order.
 
Allright, so the updated list:

Mfly: 10
pinocchio: 2
herb1diaz: 4
jormajj: 2
Bones13: 4
AR2: 2
mordikai: 2
SeanB06: 2
atupi: ?
danbmellow: ?

I will get a quote for ~30 boards and PM you the price including shipping and payment details. If you all then can PM me your shipping address, I can do a final check if the shipping costs are correct.

I will go on holiday somewhere next week and return at the beginning of August. I will then immediately place the order.