[MOVED] Best op-amp IC for audio purpose

[T3STY]

For those who might remember my op-amp and RC filters based equalizer project, well, I am now thinking to build one. Although, not all op-amps are suitable for audio purpose and I don't know any suitable one.
Do you guys know any op-amp IC suitable for audio purposes? I don't seek any particular number of op-amps in the IC, it will be fine with 1, 2 or 4.

 

[godfreyl]

NE5532 is very good for most audio applications but it's input bias current may be to high for your equalizer circuit because the bias resistors are very high value (1 megohm).

For this circuit JFET input opamps would be a better choice because they have very low input bias current. I would probably use TL074 (or maybe LF347).

I'm sure there are more modern opamps now that may be better (and more expensive), but the ones above should be plenty good enough.

 

[FvM]

NE5532 is very good for most audio applications but it's input bias current may be to high for your equalizer circuit because the bias resistors are very high value (1 megohm).

OP noise current will be even more problematic for an audio application. Every OP type has an optimal noise matched source impedance. For NE5532 it's in a few kiloohm range. For any audio circuit with higher impedance level, JFET OP are better suited, as suggested. Unfortunately, resistors will generated voltage noise on their own, so you'll probably try to use a lower resitance level in your circuit, also with JFET OP.

 

[snail888]

Hi,For audio application,as FvM suggested,op noise density is vital.A mega ohmic resistor has high voltage noise. For reduce of this noise,it's good to minimize bandwidth just meet requirement.Low input bias current and low input noise should be useful.Have a good luck

 

[T3STY]

Thanks guys! Now, I'm sure I won't have too much troubles with noise from the RC filters, I have calculated them to only use resistors up to a few kOhm. See the next table with the RC filter values:

(last column shows the frequencies calculated based on the real resistors; Capacitors start from 1uF down to 1nF)
Besides, there will be a 10k potentiometer and two 2.7k resistors after the RC filters, connected like this:

Will this cause any troubles?

 

[alexan_e]

Do you guys know any op-amp IC suitable for audio purposes?

OPA2604 is a very popular HQ audio opamp (dual) and not very expensive.
as an upgrade OPA2107 (dual) which is more expensive and for higher quality you can look at OPA637 (single) but even more expensive.

 

[snail888]

Hi,For analog circuit simulation,it's better to use specific spice model which you want to use.
For the your circuit topology,there may be some pop noise when power on when you use normal operational amplify.It's better to use specific audio op.Have a good luck.

 

[T3STY]

Thanks guys! I've decided I'll be using either OPA2604 or TL072, both dual opamp with low distortion JFET input. For this project will be just enough

 

[snail888]

Hi,if op drive speaker directly,taking more attention to pop noise when power on.

 

[FvM]

if op drive speaker directly

None of the mentioned OPs will be able to drive a speaker directly, or being exact, not achieve more than a few mW undistorted output.

 

[snail888]

Hi Fvm,I mean drive speaker via a coupled capacitor.

 

[FvM]

Hi Fvm,I mean drive speaker via a coupled capacitor.

The mW output power calculation holds with or without capacitor. Just review OP data sheets and consider P = I²R.

 

[T3STY]

I actually don't really care about the pop noise on turn-on, this project will be for fun and for the electronics exam, not for a HiFi device Thanks for the suggestions though