Hello everyone , wonder if you have any suggestions ?
I recently built pair of mono block amplifiers using a couple of old ILP power amp modules and individual toroidal transformers . Due to the age of these modules when I purchased them I found the power supply capacitors were passed there best so I replaced those .
The two amplifiers are identical and wired in the same way using star earthing techniques . They take there audio inputs from the two subwoofer outputs on my Denon AVR . The only difference is one takes its power via an IEC cable from the other and is controlled my one master power switch.
The one that plugs into the other (slave) has slight varying mains hum problem which is louder sometimes than others .The other is completely silent .
You clever people have any idea why this might be and how to cure it ?
Thanks in advance
I recently built pair of mono block amplifiers using a couple of old ILP power amp modules and individual toroidal transformers . Due to the age of these modules when I purchased them I found the power supply capacitors were passed there best so I replaced those .
The two amplifiers are identical and wired in the same way using star earthing techniques . They take there audio inputs from the two subwoofer outputs on my Denon AVR . The only difference is one takes its power via an IEC cable from the other and is controlled my one master power switch.
The one that plugs into the other (slave) has slight varying mains hum problem which is louder sometimes than others .The other is completely silent .
You clever people have any idea why this might be and how to cure it ?
Thanks in advance
Hi mbrennwa . I think I know what your asking so I just did a little experiment .
I connected the humming amp up to an independent power connection an disconnected the audio input from the Denon and the hum is still there .
With them both being earthed in exactly the same way it looks like the problem may be deaper set . The power supply for the ILP HY 2005 ‘s is just a bridge rectifier and two 10,000uf caps which like I mentioned are brand new .
Sometimes I can switch on and no hum at all , sometimes louder sometimes quieter !!
Is your pic to do with Tubular Bells by the way ?
I connected the humming amp up to an independent power connection an disconnected the audio input from the Denon and the hum is still there .
With them both being earthed in exactly the same way it looks like the problem may be deaper set . The power supply for the ILP HY 2005 ‘s is just a bridge rectifier and two 10,000uf caps which like I mentioned are brand new .
Sometimes I can switch on and no hum at all , sometimes louder sometimes quieter !!
Is your pic to do with Tubular Bells by the way ?
Ok. I'd suggest to check first if the hum really happens in the amp itself:
- What if you swap the audio inputs?
- What if the audio inputs are shorted to GND? (note: if you just disconnect the audio input, you might actually get more hum!)
Nope. I actually had to google for "tubular bells" first...
Finally got round to trying this today after busy weekend . It didn’t get rid of the initial hum/buzz but it added a lower bass hum note .
???
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