Hello,
I have a question regarding a small circuit I would like to implement for the VBIGC amplifier.
My requirement is:
1. To switch on the mains supply for the LM3875 after about 1 minute.
2. To switch on the mains supply for the LM3875 using a softstart.
Unfortunately I am a software engineer and have no electronic experience
I attached a circuit which makes sense to me from a logical point but do you guys think this could work electronically?
The upper part is the relay switches and the bypassing resistors.
The middle part turns on after about 70 seconds.
The lower part of the circuit turns on the first relay and after the softstart delay (approx. 3 secs) the second relay.
Excuse my newbish ignorance if the electronic part is nonsense. I'd appreciate any help.
Bye,
Sergiusz
I have a question regarding a small circuit I would like to implement for the VBIGC amplifier.
My requirement is:
1. To switch on the mains supply for the LM3875 after about 1 minute.
2. To switch on the mains supply for the LM3875 using a softstart.
Unfortunately I am a software engineer and have no electronic experience
I attached a circuit which makes sense to me from a logical point but do you guys think this could work electronically?
The upper part is the relay switches and the bypassing resistors.
The middle part turns on after about 70 seconds.
The lower part of the circuit turns on the first relay and after the softstart delay (approx. 3 secs) the second relay.
An externally hosted image should be here but it was not working when we last tested it.
Excuse my newbish ignorance if the electronic part is nonsense. I'd appreciate any help.
Bye,
Sergiusz
sergiusz said:
i think this step is unnecessary.
just drop a relay unit(1 minute delay) befor the second coils of tori
fyi,http://www.diyaudio.com/forums/showthread.php?s=&threadid=48118
-Z
Hello digi01,
Thank you very much for the reply. The background is that I built a VBIGC with two manual switches, one for the tube supply and the second for the LM3875s which I turned on manually after about a minute.
The problem is that due to the big inrush current (I use two 250VA xformers for the LM3875s) my household fuses blew regularly ... not always but sometimes.
That's the background ... I'd like to automate the process of switching on the amp and avoid blowing fuses
BTW, I found an error in the relay circuit which I corrected (I do not need a double switch relay on the second end):
Anyway do you think this circuit would work?
Best regards,
Sergiusz
Thank you very much for the reply. The background is that I built a VBIGC with two manual switches, one for the tube supply and the second for the LM3875s which I turned on manually after about a minute.
The problem is that due to the big inrush current (I use two 250VA xformers for the LM3875s) my household fuses blew regularly ... not always but sometimes.
That's the background ... I'd like to automate the process of switching on the amp and avoid blowing fuses
BTW, I found an error in the relay circuit which I corrected (I do not need a double switch relay on the second end):
An externally hosted image should be here but it was not working when we last tested it.
Anyway do you think this circuit would work?
Best regards,
Sergiusz
For inrush limiting I usually use a thermistor in series with the transformer primaries.
For turn on delay of the tube supply I'm using a 555 timer, like the one posted by Franz G:
http://www.diyaudio.com/forums/showthread.php?s=&postid=480087&highlight=555#post480087
Very simple and works like a charm.
For turn on delay of the tube supply I'm using a 555 timer, like the one posted by Franz G:
http://www.diyaudio.com/forums/showthread.php?s=&postid=480087&highlight=555#post480087
Very simple and works like a charm.
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