Electronics: OPAMP tests into a 270 ohm load
A friend was modifying a cheap headphone amp, and was wondering which OPAMP would work the best.So I created a similar circuit and measured several different OPAMPS loaded with 270 ohms as a 'typical' headphone load.
Note: Don't only look at the headline THD figure - also note the harmonic distortion even for some that measured well.
Measurement parameters:
PSU: 15 - 0 - 15 Gain: 2.2 Output: 2.7V RMS Load: 270 ohms
Opamp | THD | Notes |
---|---|---|
LM4562NA | 0.00027% | no data |
NE5532N | 0.00160% | Philips |
NE5532N | 0.00141% | Signetics |
NE5532N | 0.00090% | Texas |
NJM2043DD | 0.00101% | JRC / NJM |
NJM2068DD | 0.00090% | JRC/NJM |
NJM4558DD | 0.00604% | JRC / NJM |
NJM4565DD | 0.00502% | JRC / NJM |
NJM4580DD | 0.00082% | NJM / JRC |
OPA2134P | 0.02294% | BB |
OPA2604AU | 0.00132% | Sample #1 - brand unknown |
OPA2604AU | 0.00139% | Sample #2 - brand unknown |
![OPAMP tests 270 ohms - LM4562NA](media/opamp_tests_270_ohm/fullsized/lm4562na.png)
![OPAMP tests 270 ohms - NE5532N](media/opamp_tests_270_ohm/fullsized/ne5532n.png)
![OPAMP tests 270 ohms - NE5532N_PHILLIPS](media/opamp_tests_270_ohm/fullsized/ne5532n_phillips.png)
![OPAMP tests 270 ohms - NE5532N_SIGNETICS](media/opamp_tests_270_ohm/fullsized/ne5532n_signetics.png)
![OPAMP tests 270 ohms - NE5532P_TEXAS](media/opamp_tests_270_ohm/fullsized/ne5532p_texas.png)
![OPAMP tests 270 ohms - NJM2043DD](media/opamp_tests_270_ohm/fullsized/njm2043dd.png)
![OPAMP tests 270 ohms - NJM2068DD](media/opamp_tests_270_ohm/fullsized/njm2068dd.png)
![OPAMP tests 270 ohms - NJM4558DD](media/opamp_tests_270_ohm/fullsized/njm4558dd.png)
![OPAMP tests 270 ohms - NJM4565DD](media/opamp_tests_270_ohm/fullsized/njm4565dd.png)
![OPAMP tests 270 ohms - NJM4580DD](media/opamp_tests_270_ohm/fullsized/njm4580dd.png)
![OPAMP tests 270 ohms - OPA2134P](media/opamp_tests_270_ohm/fullsized/opa2134p.png)
![OPAMP tests 270 ohms - OPA2604AU](media/opamp_tests_270_ohm/fullsized/opa2604au.png)
![OPAMP tests 270 ohms - OPA2604AU_SAMPLE2](media/opamp_tests_270_ohm/fullsized/opa2604au_sample2.png)