Text only | Text with Images

Analog-Precision Board

Products by Analog-Precision => Ultimate-Preamplifier by Analog-Precision => Performance and Measurements => Topic started by: Tranquility Bass on September 14, 2020, 03:46:38 PM

Title: Tube Emulation Tests
Post by: Tranquility Bass on September 14, 2020, 03:46:38 PM
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 !!


Title: "Signal Tube" emulation mode distortion test at -3dBFS
Post by: Tranquility Bass on September 14, 2020, 03:49:16 PM
P1050066.JPG

Scope shows some distortion as expected !

Tube Emulation (Scope-Signal Tube).png

Only the friendly 2nd harmonic present though !

Tube Emulation 1(THD-Signal Tube).png

Distortion vs Amplitude Test

Tube Emulation (THD-Sweep).png

Title: "Power Pentode" Tube emulation mode distortion test at -3dBFS
Post by: Tranquility Bass on September 14, 2020, 03:50:42 PM
P1050067.JPG

Scope shows more distortion than Signal Tube profile !

Tube Emulation (Scope-Power Pentode).png

Only 2nd and 3rd harmonic present !

Tube Emulation 1(THD-Power Pentode).png
Title: "Power Triode" Tube emulation mode distortion test at -3dBFS
Post by: Tranquility Bass on September 14, 2020, 07:53:45 PM
P1050068.JPG

Scope shows even more distortion than Power Pentode as expected !

Tube Emulation (Scope-Power Triode).png

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

Tube Emulation 1(THD-Power Triode).png
Text only | Text with Images