Hi Guys - first post here:
The amp FX502S PRO I have gets quite warm when I am not using it but then the temperature drops considerably when I am listening to some music. Is this normal for Class D amps or maybe the OpAmps self oscillate at high frequency?
This was happening with the original NE5532 OpAmps. I replaced them with OPA2604 - the same situation in terms of temperature.
Speaking of sound difference - it is really difficult to tell, however one of the channels now have popcorn noise that is clearly noticeable when I crank up the volume to max without any audio input. I got the OPA2604 on AliExpress - they were used so I am guessing one of them is shot.
By the way OPA2604 appears to have much less gain than the original NE5532.
Not wanting to admit defeat and go back to the NE5532 I ordered SOIC8 to DIP8 adapters with OPA1656 installed.
OPA1656 is high gain bandwidth product - so if there is indeed self oscillation - I don't think this OpAmps will solve the problem.
I don't have access to oscilloscope - is there any other way to check for self oscillation?
Cheers,
E.D.
The amp FX502S PRO I have gets quite warm when I am not using it but then the temperature drops considerably when I am listening to some music. Is this normal for Class D amps or maybe the OpAmps self oscillate at high frequency?
This was happening with the original NE5532 OpAmps. I replaced them with OPA2604 - the same situation in terms of temperature.
Speaking of sound difference - it is really difficult to tell, however one of the channels now have popcorn noise that is clearly noticeable when I crank up the volume to max without any audio input. I got the OPA2604 on AliExpress - they were used so I am guessing one of them is shot.
By the way OPA2604 appears to have much less gain than the original NE5532.
Not wanting to admit defeat and go back to the NE5532 I ordered SOIC8 to DIP8 adapters with OPA1656 installed.
OPA1656 is high gain bandwidth product - so if there is indeed self oscillation - I don't think this OpAmps will solve the problem.
I don't have access to oscilloscope - is there any other way to check for self oscillation?
Cheers,
E.D.
If you or anyone else needs an oscilloscope this one is very inexpensive and works very well indeed: https://www.aliexpress.com/item/32795060636.html?spm=a2g0o.productlist.0.0.5ccb7b1eDRzb2h&algo_pvid=f28ce5d9-6158-461f-b0dd-9cb6713bf468&algo_exp_id=f28ce5d9-6158-461f-b0dd-9cb6713bf468-0&pdp_ext_f={"sku_id":"64013452189"}&pdp_pi=-1;19.14;-1;-1@salePrice;GBP;search-mainSearch
Cheers
As used by Eddy Bergman: https://www.eddybergman.com/2019/11/synthersizer-build-part-3-triangle-to.html
Thanks! This one is surprisingly inexpensive.
One question though - the bandwidth is only 0-200kHz - would this be enough to detect some high level oscillation like 20 MHz? It would probably appear like some noise on the screen?
One question though - the bandwidth is only 0-200kHz - would this be enough to detect some high level oscillation like 20 MHz? It would probably appear like some noise on the screen?