Hello all,
I have an Aikido / NCore setup that gets powered on and off all at once (I know I know...).
The config always had some nasty power on / power off noises...so I decided to add a preamp timer circuit that powers a simple relay to RCA outs. I have the NC of the relay floating, and the NO (timer power to close) direct to rca/amp. See attached...
Power up works great - no noises on power up...but still has a bit of a nasty pop on shutdown.
Concern #1 the preamp out of Aikido to relay is floating while powering up via timer (there is a 1M from output to ground on Aikido board)
Concern #2 the shutdown pop...I could put a 470k at RCA center pin to ground? When all "on" there is the 1M on Aikido and this 470K in parallel, so not per design
Any advice to get Concern #2 shutdown pop to stop? Concern #1 should not be problem, correct?
I worry about damaging the NCore amp modules...
I have an Aikido / NCore setup that gets powered on and off all at once (I know I know...).
The config always had some nasty power on / power off noises...so I decided to add a preamp timer circuit that powers a simple relay to RCA outs. I have the NC of the relay floating, and the NO (timer power to close) direct to rca/amp. See attached...
Power up works great - no noises on power up...but still has a bit of a nasty pop on shutdown.
Concern #1 the preamp out of Aikido to relay is floating while powering up via timer (there is a 1M from output to ground on Aikido board)
Concern #2 the shutdown pop...I could put a 470k at RCA center pin to ground? When all "on" there is the 1M on Aikido and this 470K in parallel, so not per design
Any advice to get Concern #2 shutdown pop to stop? Concern #1 should not be problem, correct?
I worry about damaging the NCore amp modules...
Attachments
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You should worry.
This is best done using the NC contacts directly shorting from the outputs to ground. The muting relay must drop out immediately upon turn-off. I've done this with a reverse 1N4148 diode connected between the timing capacitor and
the timer's raw DC supply.The raw DC supply typically will drop out quickly enough if it also feeds the tube filaments,
and if the 5V timer regulator has a reverse diode across it for fast turn-off.
If it is still not fast enough, add a bleeder resistor after the diode rectifier that is small enough to discharge more quickly.
If you need even faster operation, the best possible scenario is a pair of extra contacts on the AC power switch.
Use those contacts to directly short the timing capacitor upon power turn-off. That will definitely work.
If the timing capacitor is an electrolytic, add a small series resistor in the relay contact circuit, around 100R,
to limit the short circuit current of the capacitor.
This is best done using the NC contacts directly shorting from the outputs to ground. The muting relay must drop out immediately upon turn-off. I've done this with a reverse 1N4148 diode connected between the timing capacitor and
the timer's raw DC supply.The raw DC supply typically will drop out quickly enough if it also feeds the tube filaments,
and if the 5V timer regulator has a reverse diode across it for fast turn-off.
If it is still not fast enough, add a bleeder resistor after the diode rectifier that is small enough to discharge more quickly.
If you need even faster operation, the best possible scenario is a pair of extra contacts on the AC power switch.
Use those contacts to directly short the timing capacitor upon power turn-off. That will definitely work.
If the timing capacitor is an electrolytic, add a small series resistor in the relay contact circuit, around 100R,
to limit the short circuit current of the capacitor.
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So relay isn't "fast enough" on shutdown?
BTW - This is the timer circuit I am using... https://www.ebay.com/itm/321746593997
BTW - This is the timer circuit I am using... https://www.ebay.com/itm/321746593997
Yes, very good. Some circuits do need a turn-on time delay as well, so that function does need a timer.
OK, did the addition, but pop still there...so tried a few different amps and all were good - no shutdown pop (or greatly reduced)...Apparently the shutoff pop is on the NCORE amp only...weird.
Also when I switch the AC on/off via switch on amp, no shut down pop on the NCores......I may have to rethink the whole Turn on / Turn off all at once when I turn on my computer (I am so lazy), or just use an amp that has no issues with the arrangement I have...
Also when I switch the AC on/off via switch on amp, no shut down pop on the NCores......I may have to rethink the whole Turn on / Turn off all at once when I turn on my computer (I am so lazy), or just use an amp that has no issues with the arrangement I have...
I have same problem with bang noise when power off my 4p1l (sometime i forgot to turn off amp first )
i use a delay on with relay but to slow to help on power off
i have now done this use a 24vac relay -- where the 230vac is mounted on same contact as the 4p1l and then use a litle trafo to feed the 24vac relay ..this mute the output on the 4p1l together with the delay on
the 24vac goes fast off when power is lost (no caps or timer to hold back)
let me hear what you think about this ..
Best Bjarne
i use a delay on with relay but to slow to help on power off
i have now done this use a 24vac relay -- where the 230vac is mounted on same contact as the 4p1l and then use a litle trafo to feed the 24vac relay ..this mute the output on the 4p1l together with the delay on
the 24vac goes fast off when power is lost (no caps or timer to hold back)
let me hear what you think about this ..
Best Bjarne
Just connect a on delay circuit to the heater supply. The heater supply has very fast low voltage so delay circuit goes off.
Works for me all the time.
Works for me all the time.
I designed a speaker protect circuit.
It had 4 second power up delay before connecting speakers to amp.
It had 20mS power down (mains fail detect) detect before disconnecting speakers to amp.
It also had over current detect.
I got the speed up by using 2 mosfets back to back to driver speaker output and using a PIC microcontroller.
It had 4 second power up delay before connecting speakers to amp.
It had 20mS power down (mains fail detect) detect before disconnecting speakers to amp.
It also had over current detect.
I got the speed up by using 2 mosfets back to back to driver speaker output and using a PIC microcontroller.
And you should use the free contact of the relay to control amp/on signal of the ncore. See my schematic.
Do not connect as in our schematic disconnecting the signal but switch signal to ground.
Do not connect as in our schematic disconnecting the signal but switch signal to ground.
the big bang when power down by accident is shocking maybe a good thing is to have protection on poweramp