Parameter for Virtual Supply Voltage

MaVo

Member
Hello,

I'm just curious if it is possible to change the virtual supply voltage within the amp modeling? The reason I'm asking, is because of a recent episode of Rig Rundown of AC/DC. They use their own power supply to run their Marshalls at a different supply voltage. This means effectively a lower operating voltage for the Tube stages and a different behaviour (lower/higher voltage on the anode/plate). Since the supply frequency is exposed to the user, I'd like to know if it is also possible to expose the effective value of the virtual supply voltage to the user? Or can the user replicate this behaviour by changing the voltage offset of the power tubes (Power Amp Bias) to lower values?


Here's the video at about 9:30 min. they introduce the power supply:

 
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No. Sag controls the magnitude of the supply voltage drop, when the power amp is pushed and draws more current from the power supply. The voltage drop of sag is just temporary if you play. What I mean is a static change of the virtual supply voltage from e.g. 240 V to 236 V.
 
Both supply voltage and supply frequency are in the advanced tab on the amp.

But in the clip, they're talking more about regulation than anything else. 236VAC is less than 2% difference than 240VAC nominal, the equivalent of running at 118VAC instead of 120VAC in North America. The 'variac' effect is generally where you're talking changes of 10% or more.

I think they're just concerned with safety and consistency. He mentions running at 60Hz everywhere; that wouldn't result in anything audible (other than the note generated by the hum, of course), but it would theoretically have power transformers running cooler.
 
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