[HELP] asymmetric output op amp

[Wahyu]

Hello All,

i need help, i have output preamp asymmetric swing,
i use two IC preamp NE5534 non-inverting input.

Output Pin 6 , IC-1



Output Pin 6 , IC-2

at IC2 pin 6 positive swing not same as negative swing, how to solve this problem,

Thanks,

Wahyu

[Wahyu]

[qute1]

Swap in a known good 5534 (NE5534N for preference Texas or ON) looks like its not recovering properly unless your layout is very noisy.

[Wahyu]

Swap in a known good 5534 (NE5534N for preference Texas or ON) looks like its not recovering properly unless your layout is very noisy. [ATTACH]44103[/ATTACH]

I have been swap IC-2 LME49710, same result, max swing at around 2V, and yes my room it's very noisy,

Thank for reply

Regard,
Wahyu.

[kt315]

the swing is NOT related to a noise in your room. swing is self resonance of a coil. any coil has L and C. in reality that is just RESONANCE CONTOUR.
we recall it like 'parasitic resonance' or 'unwanted resonance', in russian - SELF resonance.
for good coil diapason of SR is 500-600 kHz. for best coil, we recall them SPEED COIL, or BASKET TYPE COIL, a coil with lowest C,
this is >550 kHz.

[green]

Just spent more time than it should have with a problem measuring ferrite decay because I didn't make the right measurements. Some thoughts, maybe correct or not. Noise doesn't look like coil resonance, frequency maybe correct but doesn't decay(stays constant for over 30usec). You could remove the coil and jumper the input to see if noise changes. Fairly high noise level, I would be interested in what is causing it. If you want symmetrical output use a RRO op amp for the second amp. Specs for NE5534 show doesn't swing to rails but couldn't find what to expect with +- 5v supplies.

[kt315]

reading the posts i am still more and more convinced i must open new thread and copy all answers of Eric from PI Tech Forum.
thats really strange for me you do not read the forum while english is your native (you are like a fish in the water with english
while i am the fish taken off the water).

[Wahyu]

the swing is NOT related to a noise in your room. swing is self resonance of a coil. any coil has L and C. in reality that is just RESONANCE CONTOUR.
we recall it like 'parasitic resonance' or 'unwanted resonance', in russian - SELF resonance.
for good coil diapason of SR is 500-600 kHz. for best coil, we recall them SPEED COIL, or BASKET TYPE COIL, a coil with lowest C,
this is >550 kHz.

Just spent more time than it should have with a problem measuring ferrite decay because I didn't make the right measurements. Some thoughts, maybe correct or not. Noise doesn't look like coil resonance, frequency maybe correct but doesn't decay(stays constant for over 30usec). You could remove the coil and jumper the input to see if noise changes. Fairly high noise level, I would be interested in what is causing it. If you want symmetrical output use a RRO op amp for the second amp. Specs for NE5534 show doesn't swing to rails but couldn't find what to expect with +- 5v supplies.

my problem is actually not in noise, but the problem is in maximum swing on positive + rail, which is only around 2V at IC-2 swap LME49710 same result, noise will disappear if I try outside or without coil installed

Thanks for reply

Wahyu.

[green]

my problem is actually not in noise, but the problem is in maximum swing on positive + rail, which is only around 2V at IC-2 swap LME49710 same result, noise will disappear if I try outside or without coil installed

Thanks for reply

Wahyu.

Depending on what the second amplifier is driving, a resistor from IC-2 output to +5v might make it symmetrical.

[Wahyu]

Depending on what the second amplifier is driving, a resistor from IC-2 output to +5v might make it symmetrical.

Hai Green, second amplifier driving 4066 and integrator, schematic ;

[green]

Hai Green, second amplifier driving 4066 and integrator, schematic ;

I would try a 4k or 5k resistor from output of 5534 to +5v and see what happens.

[Wahyu]

I would try a 4k or 5k resistor from output of 5534 to +5v and see what happens.

Hello Green,
I have tried with 4k7 and or 5k6 resistors to +5V , it still has a maximum swing of about 2 volt,

Regard,
Wahyu

[green]

Hello Green,
I have tried with 4k7 and or 5k6 resistors to +5V , it still has a maximum swing of about 2 volt,

Regard,
Wahyu

Not what I expected. Maybe someone could explain why.

[moodz]

...the texas instruments 5534 data sheet specifies within 2 volts of rail supply typical with 3 volts worst case ... so with +/- 5 volt supply from the data sheet you can expect +/- 3 volts or +/- 2 volts worst case. I have never liked running the '34 off less than +/- 12 volts for this reason ...

[dbanner]

Elementary opamp basics. Output distortion it is called.