Hi guys,
I was wondering if you could help me with some problems I'm having with a home project? The short (ish) story is that I made myself a DIY 5.1 channel amplifier for use in a home theatre set up. However, when amp is connected to an HTPC's analogue out's and makes a bit of a thump when it (the PC) turns on (I wonder that there is a DC offset to the sound card, however it's a bit of a high end card so I don't want to mess with it).
As this project represents my first foray into home electronics since my A. Levels (almost two decades ago), I turned to the internet for answers and figured that I'd put together Project 38 from the ESP site. However, rather than having the relay switch the amplifiers power supply (which is already switched by the computer's power supply), I would use a N/C relay which would trigger the kit board's sleep/mute function when there is no signal and break that loop when there is an input signal.
I can't seem to get the circuit to work on a prototype board (though instead of a relay I am using an LED, so perhaps that is incorrect?). Initially, it did seem to work correctly when I applied a signal to it, but I'd been testing it using an iPhone as a source, and it seems that it was actually turning on when I touched the iPhone rather than when the music was started.
I've checked the layout of my prototype circuit through a few times and I'm pretty certain that I have it right, I was wondering though if anyone could help with pointers to figure out what I've done wrong. Testing equipment wise I have a digital multi meter, but I understand with OP-AMP circuits I can't really use this as it is likely to change the input/output gain on the OP-AMP perhaps affecting the circuit itself.
Thanks in advance,
~Dan
I was wondering if you could help me with some problems I'm having with a home project? The short (ish) story is that I made myself a DIY 5.1 channel amplifier for use in a home theatre set up. However, when amp is connected to an HTPC's analogue out's and makes a bit of a thump when it (the PC) turns on (I wonder that there is a DC offset to the sound card, however it's a bit of a high end card so I don't want to mess with it).
As this project represents my first foray into home electronics since my A. Levels (almost two decades ago), I turned to the internet for answers and figured that I'd put together Project 38 from the ESP site. However, rather than having the relay switch the amplifiers power supply (which is already switched by the computer's power supply), I would use a N/C relay which would trigger the kit board's sleep/mute function when there is no signal and break that loop when there is an input signal.
I can't seem to get the circuit to work on a prototype board (though instead of a relay I am using an LED, so perhaps that is incorrect?). Initially, it did seem to work correctly when I applied a signal to it, but I'd been testing it using an iPhone as a source, and it seems that it was actually turning on when I touched the iPhone rather than when the music was started.
I've checked the layout of my prototype circuit through a few times and I'm pretty certain that I have it right, I was wondering though if anyone could help with pointers to figure out what I've done wrong. Testing equipment wise I have a digital multi meter, but I understand with OP-AMP circuits I can't really use this as it is likely to change the input/output gain on the OP-AMP perhaps affecting the circuit itself.
Thanks in advance,
~Dan