Retro TGM8 with TMC, Laterals and 80db OLG @ 20 KHz

Dear friends,

There was a thread by Nico Ras, (6) Another thread regarding CCS vs BOOTSTRAP | diyAudio . There was a lot of discussion about CCS vs Bootstrapping. In post https://www.diyaudio.com/community/...egarding-ccs-vs-bootstrap.134046/post-1674672 , MJL21193 suggested “We need a compromise Nico - a bootstrapped CCS!”

I remember that Dadod used it in his GEM amplifier. Also, Hugh used it in his Fetzilla. I used Hugh’s idea in my latest iteration, in toto.

When I checked the distortion products, the FFT @ 1 KHz is as below. Not very useful. Hence, I used 10 KHz for all further FFT plots.

I take this opportunity to thank dear minek, whose file of models I used extensively.

2024-10-30 Distortion FFT, 1 KHz.jpg
 
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The schematics used by me to evaluate the Phase and gain margins is attached below. The .asc file should run easily, thanks to minek123. Thanks to Bimo for the tian scheme. Just typing tian() in the add traces window should be sufficient.
 

Attachments

  • 2024-09-11 Tian Ph & Gain Margins.jpg
    2024-09-11 Tian Ph & Gain Margins.jpg
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  • 2024-09-11 Tian Schematic.jpg
    2024-09-11 Tian Schematic.jpg
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  • Retro TGM8 mod BootstrapCC Tian.asc
    Retro TGM8 mod BootstrapCC Tian.asc
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The schematics used by me to evaluate distortion, overload behavior and square wave response are as below.
The dis curves are shown for 10 KHz and 16 Volts pk-pk, as this will provide ~16 watts output power. The clipping is at +/- 20 volts, pk-pk.
 

Attachments

  • 2024-09-13 THD @16V output 10 KHz 8 ohms.jpg
    2024-09-13 THD @16V output 10 KHz 8 ohms.jpg
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  • 2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output .jpg
    2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output .jpg
    270.1 KB · Views: 61
  • 2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output BOTTOM.jpg
    2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output BOTTOM.jpg
    188.9 KB · Views: 56
  • 2024-09-15 IMD 14 & 15 kHz.jpg
    2024-09-15 IMD 14 & 15 kHz.jpg
    351.5 KB · Views: 53
  • 2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output TOP.jpg
    2024-09-15 - 10kHz SQ on 100 Hz Sine 1uf on output TOP.jpg
    202.7 KB · Views: 55
  • 2024-09-15 IMD 19 & 20 kHz.jpg
    2024-09-15 IMD 19 & 20 kHz.jpg
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  • 2024-09-15 Overload 2 volts input.jpg
    2024-09-15 Overload 2 volts input.jpg
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  • 2024-09-15 SqWave 1uf on output.jpg
    2024-09-15 SqWave 1uf on output.jpg
    203.6 KB · Views: 49
  • 2024-09-15 SqWave 100nf on output.jpg
    2024-09-15 SqWave 100nf on output.jpg
    208.2 KB · Views: 48
  • 2024-09-15 SqWave 100pf on output.jpg
    2024-09-15 SqWave 100pf on output.jpg
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  • 2024-09-15 THD @16V output 10 KHz 4 ohms.jpg
    2024-09-15 THD @16V output 10 KHz 4 ohms.jpg
    337.4 KB · Views: 94
  • Retro TGM8 mod BootstrapCC Dis etc.asc
    Retro TGM8 mod BootstrapCC Dis etc.asc
    11.3 KB · Views: 38
  • 2024-10-31 Schematic for THD etc.jpg
    2024-10-31 Schematic for THD etc.jpg
    277.2 KB · Views: 96
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