Hi,
If I have power trans with full wave rectifier, is it possible (and safe) to put switch between centre tap of secondary and ground to delay the B+?
I know ther is more proper B+ delay circuit out there, but I prefer the simplest one (albeit manual).
Any simpler way? Use Thermistor instead of switch?
Thanks in advance
If I have power trans with full wave rectifier, is it possible (and safe) to put switch between centre tap of secondary and ground to delay the B+?
I know ther is more proper B+ delay circuit out there, but I prefer the simplest one (albeit manual).
Any simpler way? Use Thermistor instead of switch?
Thanks in advance
Only in the case if the 370V positive is shorted.rahew,
I often forget details, as do we all.
P = E(squared)/R
370VDC and 10k = 13.7 Watts!
A 10 Watt resistor will smoke!
Or at least melt the insulation off a wire that is too close.
Prevent Forrest Fires.
I think 10W will do fine.
33k / 5W is another possebility.
Mona
... Depends how much current the amp sucks during the 'standby condition', of course.
And that depends on the resistor you place across the standby switch
Last PA amp I looked at was a 50W amp and it had 3k@5w across the standby switch.
Well, he is right, at open circuit that isHe said: "(About 370v DC across it in standby)"
It = 10k 10 Watt.
I took him Literally.
Mona
Delaying B+ is overrated and might be damaging to the power tubes.Hi,
If I have power trans with full wave rectifier, is it possible (and safe) to put switch between centre tap of secondary and ground to delay the B+?
I know ther is more proper B+ delay circuit out there, but I prefer the simplest one (albeit manual).
Any simpler way? Use Thermistor instead of switch?
Thanks in advance
What do you want to solve with this ?
Get capacitors that are rated for 500V or more.
Some are rated for 550V surge and 500V operational.
You may have to stack capacitors in series, with leakage balancing resistors across each one. You need 2X the capacitance for each one.
Keep in mind, if the output tubes ever die, the B+ will rise to 500V, just like they do at start up.
To quote the capacitor . . . Ouch!
And ask yourself, what happens if you, or someone else forgets to put the standby switch in standby before powering on the amp?
Some are rated for 550V surge and 500V operational.
You may have to stack capacitors in series, with leakage balancing resistors across each one. You need 2X the capacitance for each one.
Keep in mind, if the output tubes ever die, the B+ will rise to 500V, just like they do at start up.
To quote the capacitor . . . Ouch!
And ask yourself, what happens if you, or someone else forgets to put the standby switch in standby before powering on the amp?
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