Author Topic: Tube Emulation Tests  (Read 279 times)

David Samborsky

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Tube Emulation Tests
« on: September 14, 2020, 05:46:38 AM »
Introduction

Whilst all of the other tests posted so far are looking for the best possible distortion and noise measurement, in this case we are going in the opposite direction and purposely trying to add distortion in the same way a tube circuit does.

Measurements

In the following tests we operate different tube profiles whilst keeping the grid bias constant. In all of these tests we are mimicking the way a tube Preamplifier behaves which is exposed to a full scale signal all of the way before the volume control which is unlike a Tube Power Amplifier where the distortion increases with increasing volume control !


Conclusion

These are just three examples of what can be achieved with Tube Emulation as the grid bias control and amplifier type allows many different permutations of altering the tube linearity and hence the distortion profiles !! For tube and SET aficionados the pure 2nd harmonic distortion should be music to their ears !!


« Last Edit: September 25, 2020, 04:25:11 AM by David Samborsky »
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David Samborsky

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"Signal Tube" emulation mode distortion test at -3dBFS
« Reply #1 on: September 14, 2020, 05:49:16 AM »


Scope shows some distortion as expected !



Only the friendly 2nd harmonic present though !



Distortion vs Amplitude Test



« Last Edit: September 25, 2020, 04:19:26 AM by David Samborsky »
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David Samborsky

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"Power Pentode" Tube emulation mode distortion test at -3dBFS
« Reply #2 on: September 14, 2020, 05:50:42 AM »


Scope shows more distortion than Signal Tube profile !



Only 2nd and 3rd harmonic present !

« Last Edit: September 25, 2020, 04:17:43 AM by David Samborsky »
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David Samborsky

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"Power Triode" Tube emulation mode distortion test at -3dBFS
« Reply #3 on: September 14, 2020, 09:53:45 AM »


Scope shows even more distortion than Power Pentode as expected !



Only 2nd, 3rd and 4th harmonic present ! No higher order harmonics in sight which should be music to the ears of tube aficionados ;)

« Last Edit: September 25, 2020, 06:44:43 AM by David Samborsky »
The home of the Ultimate-Preamplifier and Ultimate-Amplifier ! https://www.analog-precision.com/