Recent content by xmag

This confirms that I am blind :( ! Thanks, John! I will read and learn!

As the thread topic: Feedback loop what exactly does it do Can't find anything about it in the manual that explains exactly what the loop does.

How to remove both ripple from switched power supplies and "motorboating" from battery operation and switched power supplies with ripple filter: Before ripple filter: After ripple filter: I have run an RTA in REW with a microphone to include the microphone amplifier in the...

Now I know what the error is: It is known especially in tube amplifier builders. The phenomenon is called "motorboating" = https://www.electronicspoint.com/forums/threads/motorboating-what-exactly-is-it.267151/ In addition to the fact that tube amplifiers can suffer from the problem, ordinary...

Now I know what the problem is: It is known especially in tube amplifier builders. The phenomenon is called "motorboating" https://www.electronicspoint.com/forums ... it.267151 / In addition to the fact that tube amplifiers can suffer from the problem, ordinary amplifiers with battery operation...

Yes, I will try to pull completely separate power supply wires when I have time. When I connect the power supply and disconnect the batteries, it works perfectly. But switched power supply gives disturbances over 3 khz. The power supply is connected from the outside through a power socket. I...

I first thought it might be so. Has connected signal earth and power lines in different ways to test. No difference. Signal ground has no closed circuits, everything starts at central signal ground and ends where it is needed without going anywhere. The power wires go straight from the battery...

Now I am really confused, it will be the same result with batteries as with power supplies and DC filters. If I remove the DC filter for the power supply , the measurements will be good (but higher distortion over 3kHz). But with batteries, I can not solve the problem of removing DC filters...

Have now rebuilt my test-Matrojig to battery operation. 10 AA batteries 1.2v at 2800 mAh becomes 28Ah. A few days should be enough to measure before the batteries need to be charged. It became cheaper than building a line power supply. Will return with measurement results later.

Yes, I'm on the to-do list.

Have continued to test. I have located the problem with the DC filter to the microphone amplifier. With filters for the whole system, I get a frequency arc with the middle at 30hz but low distortion. If I connect the microphone amplifier past the filter, the frequency arc disappears but now the...

THANKS!! Yes, of course it is. Why did I not think about it? Probably because I was excited to find the error ;)

I have solved the problem with the low frequencies. It was the power supply's current filter that gave the signal in the low base. It was not visible in the noise measurements !? This is what the measurement now looks like 30 cm distance:

The noise floor is far below the base level. However, the distortion follows the sub frequency curve exactly and is approximately 25dB below (THD = approximately 20%). I was in that it could be the distortion as the cause but have now measured in several different ways and it seems (I am far...

Fler med samma sub-kurva: Do not know how it is measured: Measured by free element only: http://www.troelsgravesen.dk/HES/215GMFvsRTF.jpg Do not know how it is measured: https://www.diyaudio.com/community/attachments/er18_raw_nearfield-gif.690241/ Measured on tweeter horn driver (without...