Since the transformer has a center-tap then the resistors are not needed.A pair of equal value resistors should be connected across C1 and C2 so as to stabilise the earth to be a half of the +Vcc and -Vcc. Try 100 ohms, its value will depend on the currents in the respective voltage lines.
Frank
Since the transistors are not powered then the poor opamp has no negative feedback and is clipping like crazy.
The digital 'scope seems to have a very low sampling frequency and is chopping up the waveform. The waveform is odd that it does not show a negative swing nor 0V and shows only the most positive part.
Open loop output impedance of OPA is very high, especially at 20Hz
Although it is reduced significantly by feedback ratio. (Aol/Acl) Thus raising the Acl gain will also raise the source impedance.
The MJE3055 has high output current but a wide tolerance on hFE which means input impedance is limited by hFE*Re +240+10Ω, where Re=0.1
Lower the gain selector R value will increase gain but also output impedance.
I am not familiar with this chip, but it does not seem to be working as expected.
Replace MJE's with a 2K load R for testing then 1K. Drive full scale and Note the drop from rail and compare vs f. 20Hz to 20KHz
Also consider other parts.
Is there any reason why you don't want to use the recommended configuration for higher current in the data sheet?
I did look at that, but I do wan't this amplifier to be fully class A, I need to warm my fingers during winter. I also can't see how that configuration won't add crossover distortion as the gain between 0.7V and -0.7V will be less than during the rest of the swing, right?
How are you measuring OPA output current? twin probe in diff mode? (A-B)
Simplified design, with critical details not shown;
- diode selection or adding ESR and high matching hFE in Q1,2,, thermal coupling diodes to Q
They don't produce data sheets and app notes because they have nothing better to do. Below you can see that simulation results show superior performance using the configuration in the data sheet.
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