Hi everyone just wondered if you guys had any ideas on this little problem . I have recently built a couple of mono block amplifiers built aroun a pair of old
ILP power amp modules . I am using a couple of cheap Chinese low pass filters which are just being used for level control as my Denon AVR does all the DSP. The first one works perfectly but because I have to wait for the Volt drive unit for the second sub I only tried the second one yesterday.
I am getting random distortion at high volume levels which seems to get worse and better all the time . I have tested the amp module bypassing the filter and all seems fine so I’m assuming it’s the LPF .
You guys got any idea what can go wrong with these . It’s based around 2 NE5532 op amps and the rest including the power rectifier and smoothing are all on board too .
Any ideas?
ILP power amp modules . I am using a couple of cheap Chinese low pass filters which are just being used for level control as my Denon AVR does all the DSP. The first one works perfectly but because I have to wait for the Volt drive unit for the second sub I only tried the second one yesterday.
I am getting random distortion at high volume levels which seems to get worse and better all the time . I have tested the amp module bypassing the filter and all seems fine so I’m assuming it’s the LPF .
You guys got any idea what can go wrong with these . It’s based around 2 NE5532 op amps and the rest including the power rectifier and smoothing are all on board too .
Any ideas?
Hi Bandyaker,
Please,Avoid guesswork by posting A Picture of the Filter(Shematic) and the Input Impedance +Max operating Level for the ILP power amp.
b🙂
An externally hosted image should be here but it was not working when we last tested it.
Not sure if you can see that image , not posted picture on here before .
No schematic sadly .
The input sensitivity of the ILP amp modules are 500mV
Input impedance 100k ohms
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I'm not really that good with electronics but the last board I built had a positive and a negative DC input on the board. That board is not showing a difference on the 18v inputs ?
Rob.
Rob.
I’m using a 12v-0-12v transformer . Like I said in the original post I have made 2 off these and the first one works perfectly .
I Am thinking must be a faulty component on the board , maybe in the power supply circuitry ?
I Am thinking must be a faulty component on the board , maybe in the power supply circuitry ?
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Bjorne it’s exactly the same board but mine cost £3 ($3.80) from China . Korpberget swapped out the opamps with som rc 4580 ones I had lying around . Still the same distortion . Ordered a replacement LPF so hopefully will solve the problem ,fingers crossed
Light bulb moment
Well for Christmas I got a huge dose of man flu so instead of going back to work I am sat here wallowing in self pity .
Started thinking about my distortion problem and something occurred to me . I mentioned at the start of the post that I was using a pair of vintage ILP encapsulated power amplifiers which have integrated power supply boards . You just hook it up to a transformer give it an input and connect to a speaker and your good to go .
I had ILP ampliers back in the 1980’s and they have not been made for some time now ( check out IlP 2005) . So when I acquired these recently I knew they were new/old stock .
My original subwoofer plate amp which I purchased in 2006 recently started to distort and hum and after contacting the manufacturer they recommended swapping out the electrolytic capacitors on the power supply . After doing this low and behold it was good as new again.
Why did this not occur to me before now ? These amplifiers have been stuck on a shelf for maybe 20+ years in which time the 4700uf caps have almost certainly dried out and gone bad ....
Thanks to good old eBay have sourced replacements and hopefully in a week or so when they arrive all my distortion problems will be solved once more .
I will let you know how I get on .... Now back to wollowing in self pity ..
Well for Christmas I got a huge dose of man flu so instead of going back to work I am sat here wallowing in self pity .
Started thinking about my distortion problem and something occurred to me . I mentioned at the start of the post that I was using a pair of vintage ILP encapsulated power amplifiers which have integrated power supply boards . You just hook it up to a transformer give it an input and connect to a speaker and your good to go .
I had ILP ampliers back in the 1980’s and they have not been made for some time now ( check out IlP 2005) . So when I acquired these recently I knew they were new/old stock .
My original subwoofer plate amp which I purchased in 2006 recently started to distort and hum and after contacting the manufacturer they recommended swapping out the electrolytic capacitors on the power supply . After doing this low and behold it was good as new again.
Why did this not occur to me before now ? These amplifiers have been stuck on a shelf for maybe 20+ years in which time the 4700uf caps have almost certainly dried out and gone bad ....
Thanks to good old eBay have sourced replacements and hopefully in a week or so when they arrive all my distortion problems will be solved once more .
I will let you know how I get on .... Now back to wollowing in self pity ..
Just measure the voltage between ground and the IC pins, you must find + and - voltage of the same value there. If not you have a problem with the supply. Just remove the IC for measuring, makes it simpler.
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