OK, so they haven't actually implemented anything special, just a connection to the standard hypex smps standby.
Exactly opposite to the established standard, and rather inconvenient for users, but I am sure it made the circuitry somewhat easier to implement.
Any practical reason not to use a solid state relay to pull down that SMPS input to GND, which would enable the PSU and the amp itself ? They need a much smaller current to operate and the input voltage range is usually more universal like 5 - 30 Volt.
You still need an external voltage to pull up the input. Not that that is hard to do, but why not just use a transistor instead of a solid state relay?
But the external voltage is already there: the 12VDC trigger signal from either a preamp or an AVR or whatever. You just have to route it from i.e. a 3.5 mini socket to that solid state relay, don't you ?
I usually try to follow that "keep it simple Simon..." rule.
I usually try to follow that "keep it simple Simon..." rule.
Unfortunately the 12V signal *isn't* there when in "off" (which is when you need it for the hypex input).
Its only there when the triggering device is powered up ie a Pre Amp, while the preamp is off your power amp has a 0V signal on the SMPS stand by input meaning the power amp is on. What you want is a 12V on the input at all times apart from when you want to use the power amp. This would require an external power source or additional little power supply circuit in the amp.
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Judging by the Hypex specifications, Bel Canto seems to have put a voltage regulator on the trigger input. The SMPS1200 requires between 3.3 and 5.5 Volts to go into standby. (Interestingly, the standby voltage specs for SMPS600 and SMPS400 are both different, but neither is 5 to 12 V.)
In the data sheets I have, SMPS400, SMPS600 and SMPS1200 all specify as 3.3-12 V for SMPS Standby.
That's what I saw for the SMPS600. The SMPS400 was 3.3 to Vaux (21 V typical). I looked at hypexpro.com for the specs of SMPS1200 and 400, and hypex.nl for SMPS600.
Ummh, really? In that case it would have been just as easy to use a normally-open as a normally-closed relay...
http://www.hypex.nl/docs/SMPS400_datasheet.pdf states "DC voltage on J5:1 - Min 3.3, Max 12 Vdc in section 7.7.
Edit: so does http://www.hypexpro.com/wp-content/uploads/2014/Datasheets/SMPS400_datasheet.pdf
Indeed, I have mistakenly read the amp standby. The SMPS1200 is however different to the other two, and the Bel Canto amp would appear to use some regulation of the trigger voltage.
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