If the SMPS has an instant off power then you don’t need the low capacitance PSU bonus board. But SMPS doesn’t have an AC secondary that you can use to power the low capacitance PSU. You may need to use some sort of logic that the PSU or your own amp circuitry has to activate the optoisolator circuit.
I think Sami’s PSU’s have an open collector logic for remote switching that sinks current when amp is on. I use this for self powering the LED in the on/off switch. This same current could be routed through the remote enable connector X1 on SSR to have instant shut off. There is anode and cathode, just connect in series with the remote power switch and I think 680R resistor in series.
I'm guessing I'll need an additional switch (like the popular illuminated remote front panel switches) to get that to work. I just have a Schurter mains input switch currently.
I am having a bit of difficulty reasoning through the connections. How would I wire up the remote enable connector to the SMPS (I assume at the "stand by" connector)?
I am having a bit of difficulty reasoning through the connections. How would I wire up the remote enable connector to the SMPS (I assume at the "stand by" connector)?
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Let me dig through my notes. I’ll post a sketch on how to do it. Basically the “standby” +ve goes to the switch common through a 680R series. From the N/O pin it goes to built in LED Anode and LED cathode would normally return to GND on the standby connector. So when switch is pushed, current flows to activate switch and light LED. I am guessing that the switch LED cathode can now go to SSR anode and then cathode on SSR goes to GND on the standby connector. The question is what resistor setting will be needed to allow this to work. Also, can the switch LED be used because it might cause too much voltage drop.it might be as simple as changing to a 220R resistor etc. or you may not be able to light the switch LED and need a separate wire from the +15v aux out.
I tested it out to make sure it works on my Micro-Audio SMPS 550 R2 Class A PSU.
I connected the non-G pin of the “STDBY” plug to common pin of the DPST latching pushbutton switch with built in LED light ring. From the N/O pin on switch I connected that to the LED anode pin with a 240ohm resistor. From the Kathode pin I connected that to the SSR speaker protect board X1 connector Anode, from the X1 connector Kathode, I connected that to the G pin of the SMPS “STDBY” connector. Don’t forget to remove the jumper on the SSR to allow external logic control on X1.
Like this:
It works like a charm. Push the button and the swith LED ring light glows and there is a 2-3 second delay before the SSR LED lights up to show that the speaker is connected. Push the button off and the SSR LED instantly goes off meaning the speaker is disconnected and therefore, no turn off thump.
Here’s the back of the switch:
I used this $1 “vandal proof” 16mm waterproof stainless steel switch:
https://a.aliexpress.com/_mO3LKeK
Pick: 12V / Self latch / Ring Light pattern.
This is a really nice result because it means we can easily drive the SSR speaker protect with the built in logic of Micro-Audio SMPS’s.
I connected the non-G pin of the “STDBY” plug to common pin of the DPST latching pushbutton switch with built in LED light ring. From the N/O pin on switch I connected that to the LED anode pin with a 240ohm resistor. From the Kathode pin I connected that to the SSR speaker protect board X1 connector Anode, from the X1 connector Kathode, I connected that to the G pin of the SMPS “STDBY” connector. Don’t forget to remove the jumper on the SSR to allow external logic control on X1.
Like this:
It works like a charm. Push the button and the swith LED ring light glows and there is a 2-3 second delay before the SSR LED lights up to show that the speaker is connected. Push the button off and the SSR LED instantly goes off meaning the speaker is disconnected and therefore, no turn off thump.
Here’s the back of the switch:
I used this $1 “vandal proof” 16mm waterproof stainless steel switch:
https://a.aliexpress.com/_mO3LKeK
Pick: 12V / Self latch / Ring Light pattern.
This is a really nice result because it means we can easily drive the SSR speaker protect with the built in logic of Micro-Audio SMPS’s.
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Excellent, thank you! Question on overall power scheme: would one in theory turn on the mains switch at the IEC inlet, then use the standby switch as as the main way to operate the amp? Does the SMPS standby mode limit the power use to a minuscule amount?
Interesting on the delay option… maybe that could power the SSR board on its own?
Interesting on the delay option… maybe that could power the SSR board on its own?
In standby mode, the SMPS uses the onboard Meanwell 5W AC/DC (on some models) and a small rectifier and transformer on others. But EU requirement is <5W on standby I think.
The Delay output is strictly for logic (open collector) and cannot provide the minimum 18v 20mA needed to power the SSR.
The Delay output is strictly for logic (open collector) and cannot provide the minimum 18v 20mA needed to power the SSR.
I have not tried that yet, but that is operating the system in a mode that leaves the logic gate in an indeterminate state - there is no guarantee that it shuts off before the main rail collapses. I would guess that there is a high probability of thump. One should not power off the mains before power down from front panel. Sort of like pulling plug on a desktop computer before powering down properly.