Electronics > Projects, Designs, and Technical Stuff
Preamp noisefloor
Michaelaudio:
@magic u mean if id add a bigger cap the noise would be refuced?
But how do I change that? Carl amps for example ofc dont have a krackling/pop when u turn bass boost on
@tooki yea I thought about taking the 3118 for the tweeters and mids 3116 seems so be a bit overpowered here.
Yea its an active crossover, high pass for the high amp , high and low pass for the mid amp and low pass (with changeable crossover frequency) for the woofer amp. Can make a block diagramm later if u want.
rkabz:
This is what I think is happening with S2. The input of IC6A (pin 3) is basically floating when S2 is open, so the input bias current will charge C52 to a voltage near to the positive supply voltage (to see why check the basic schematic of the NJM4558). When S2 is closed the voltage at the output of IC5A which is at around half supply, will discharge C52 until it stabilises at the new voltage, causing the transient you are experiencing. So basically it's a (lack of) biasing issue with IC6A pin 3.
Michaelaudio:
I can imagine but can u tell me what "floating" exactly is?
So basically i can solve it, by biasing Pin 3 at Vcc/2 like on the other filters🤔
rkabz:
Floating in this case means that the input pin is not connected to a proper DC biasing source, so yes, connecting it to vcc/2 will fix it.
Michaelaudio:
So I tried biasing C51 to 12 V now, but the pop is still there.. I tried to Bias Pin 3 directly (not the right way to Do it) then there is no pop but the output signal is like 1/4 times as low as it should be..?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version