i "made" (simulated) an parallel op amp amplifier my idea is to use something like th jrc4556 as the "power" op amps and an ne5532 as the "voltage" op amp
feel free to give sugestions
feel free to give sugestions
You might want to look at TI OPA1656.
Both it and the JRC4556 feature typical offset error of 0.5mV, but the TI part specs 1mV maximum vs 6mV for the JRC. Short circuit current for the TI is 100mA.
A small cap between U5 output and its inverting input may help tame global loop stability. The TI part is very wideband, so use good supply bypassing and careful PCB layout.
Both it and the JRC4556 feature typical offset error of 0.5mV, but the TI part specs 1mV maximum vs 6mV for the JRC. Short circuit current for the TI is 100mA.
A small cap between U5 output and its inverting input may help tame global loop stability. The TI part is very wideband, so use good supply bypassing and careful PCB layout.
Very late reply but thank you now i got back into this idea and i think i could add a few more changes such us higher output resistors and a nice pcb
This has been done many times before. Personally, I prefer to simply add a discrete buffer because you can get 10x, even 100x the current without using 10x as many parts. If this is a headphone amp, then you can protect it with a ~10 Ohm series resistor. A typical circuit that can use a dual op-amp for two channels like this:
Note I cut this from a simulation of 9 different "headphone amp" experimental circuits. let me know if anyone wants that file.
Note I cut this from a simulation of 9 different "headphone amp" experimental circuits. let me know if anyone wants that file.
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read that and i got really inspired by it, im making a miniature 4 op amp version right now.
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I already paralleled 4 amplifiers togheter, and run 3 of them with a basic resistor-capacitor supply splitter yesterday, and it was loud enough to drive a speaker while connected to an source with an high enough volume.
The op amps i used were rc4558's.
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it may have just enough power to drive small speakers, now for the op amp selection, rc 4558 or ne5532
im now back home and fixing whatever mistake i made becuse the thing draws 300ma and one of the op amps became really hot
You should limit the supply voltage to the available current times the load plus a couple volts for saturation, so if you have 100mA then that's 3V peak, plus a bit gives you about +/- 4.5 or 5V. A 9V battery would be appropriate. More voltage than that is just abusing the op-amps as they hopefully current limit before they die. Most op-amps have current limiting but potentially that is pushing their SOA, and they are not meant to constantly be in that mode.
I think i should limit it to 2 op amps 1 driver 1 output, tl072 driver, rc4558 output i could either use both rc4558 channels in parallel and the spare tl072 channel as a dc servo
If you're going to play with opamps to drive cans, at least get some 4580s. Behringer equipment is full of them. 4558s are really wimpy, not much better than TL072s, I generally wouldn't want to have them driving anything less than a few kOhms.
Some go-to parts for headphone drivers would be NJM4556A (about twice the current of a 4580) or OPA1688 (less current but exemplary low distortion, quite common in audio interfaces these days). The venerable O2 amp used two of the former.
BTW, including the buffer stage in the feedback loop is dicey and requires that your buffers be substantially faster than your gain stage for stability. If it's all the same part you're probably going to need a gain setting of at least 3. Common high-performance off-the-shelf models (think Topping, SMSL, FiiO etc.) are all composite / nested feedback designs with TPA6120A2 buffers but their designers also know what they're doing.
As an aside, the beefier your circuit the more power supply bypassing it needs. 2x 220 µF may not go amiss. Also, be careful with your ground returns... aside from impedance concerns, extensive bypassing may inject power supply noise and a dedicated power ground return may be warranted.
Some go-to parts for headphone drivers would be NJM4556A (about twice the current of a 4580) or OPA1688 (less current but exemplary low distortion, quite common in audio interfaces these days). The venerable O2 amp used two of the former.
BTW, including the buffer stage in the feedback loop is dicey and requires that your buffers be substantially faster than your gain stage for stability. If it's all the same part you're probably going to need a gain setting of at least 3. Common high-performance off-the-shelf models (think Topping, SMSL, FiiO etc.) are all composite / nested feedback designs with TPA6120A2 buffers but their designers also know what they're doing.
As an aside, the beefier your circuit the more power supply bypassing it needs. 2x 220 µF may not go amiss. Also, be careful with your ground returns... aside from impedance concerns, extensive bypassing may inject power supply noise and a dedicated power ground return may be warranted.