Complete Vacuum Tube Hi-Fi Amplifier

[Craig Maier]

I constructed a simulation of a complete Vacuum Tube / Valve based Hi-Fi Amplifier using 6 VVA's within the Diamond Cut DC6's Multifilter. Each "Virtual Valve" in the line-up represents one stage of the amplifier system, resulting in a signal pathway which would run from the low-level magnetic phono cartridge input all the way through to the Power Amplifier output. The following lists the function of each amplification stage:

Virtual Valve 1: First Phono Pre-Pre Amplifier Stage.

Virtual Valve 2: Second Phono Pre-Pre Amplifier Stage.

Virtual Valve 3: First Stage of the Line Level Preamp/Tone Control Stage.

Virtual Valve 4: Second Stage of the Line Level Preamp/Tone Control Stage.

Virtual Valve 5: Power Amplifier Voltage Amplifier input stage.

Virtual Valve 6: Phase Inverter & Push-Pull Beam Power Pentode Output Stage.

With the controls set as they are in this preset, the Total Harmonic Distortion produced by this simulation is 4.33 % as measured by the Diamond Cut Spectrum Analyzer THD meter. You can easily vary the "sound" of this system by adjusting the various stages of the Hi-Fi Amplifiers Mixer Slider Controls. If you are adventerous, you can also adjust some of the other parameters. The number of possible permutations of amplifer designs are huge!

Note: This is not compatible with the DC5 version of the Diamond Cut software.

[Craig Maier]

I have re-uploaded this preset since there have been problems. Hopefully, this will fix the problem.

[dcblana]

Virtual Valve (Tube) Cascading Phase in MultiFilter

Being a former tube man long ago, I was just wondering if the virtual valve computer simulations that DC LIVE have also built in the normal 180 degree phase shift in each section, just like most normal tube circuits would do? If so, then you would have to be careful in adding in the proper odd or even amount of circuits into the multifilter, especially if you are splitting off L/R channels, processing, and recombining. Maybe this is not a problem, or is it? Any thoughts on this out there?

[Craig Maier]

It has been a long time since we created the VVA, but I believe that all of the VVA tubes are software phase corrected, despite the normal inversion that would occur in a single physical Voltage gain stage. In other words, usually a single Voltage gain stage produces 180 degrees of phase shift. Internal to the software, the tubes themselves, do that also. However we have corrected that anamoly so that summed signals (dry + wet) remain additive when using the VVA Mixer control.

keywords: Tube Phase Inversion, Amplifier Phase Inversion, VVA Phase Inversion, Valve Phase Inversion

[Craig Maier]

I just tested and verified that the above post is true; the VVA is phase corrected to 0 degrees despite the internal 180 degrees of phase shift that occurs per Voltage gain stage within the effect routine(s).