FREE: SoftAmp PSA Amp Sim


This looks awesome. A clone of the legendary Sansamp PSA-1 Amp tube amplifier, gloriously free thanks to the awesome Alexander Petrov-Savchenko.

“SoftAmp PSA is a virtual-analog guitar pre-amp supplemented with noise gate and compressor, all modeled after famous guitar gear that needs no introduction.”

“At its core there are 5 distortion stages. First three are based on op-amps with zener diodes in the feedback chain, while the last two are just op-amps being overdriven into saturation. They are followed by tonestack, speaker simulator and an output level control. Each overdrive stage has a distinct frequency shaping quality according to their names. See the EQ plot in the bottom right corner for details.”

“All stages are modeled as nonlinear filters with their outputs depending on both the frequency and the amplitude of the input signal. It gives the most accurate digital representation, compared to cascaded filter/static waveshaper approach.”

“In addition to the basic controls, there are two more knobs that control the speaker simulator parameters – Shape and Rolloff. With both knobs at 0, the speaker simulator is completely bypassed (for example, to be used with external impulse loader).”

“Giving even finer control over the gain structure, there are two more buttons – Asymmetric and Soft-Clip. The former applies to the zener diode stages and replaces the default 4.7v/4.7v zener pair with intentionally unbalanced 3.3v/4.7v pair to saturate the signal with even harmonics. The more the first three stages are overdriven, the more pronounced is the effect. See the clipping LED indicators to have a feel of which stage gets the most saturation from the signal. The Soft-Clip function applies to the two overdriven op-amps and changes their open-loop gain from 1 million to just 200. This effectively makes the transition from linear to saturated region much more softer, making the distortion less harsh and also helping the fading notes sound smoother.”

“The PSI Denoiser is noise gate with adaptive release time. It has a handy “Learn” function. Don’t play anything on your guitar and hit the Learn button. As soon as the LED goes off, the gate threshold will be automatically set to match your noise level. The noise gate is applied directly to the input signal.”

“The Squeezo Range compressor is applied to the signal right before entering the PSA pre-amp. It’s a very nonlinear, but musical sounding device. It acts as both upward and downward compressor depending on the gain and bias setting. In the original device those controls were not available for user adjustment.”



6 thoughts on “FREE: SoftAmp PSA Amp Sim

    • Hi Nerson. I believe this is just a plugin at the moment. I haven’t used it yet, but I’ve tried all of the other Softamp plugins and they are absolutely fantastic – I can’t recommend them enough. Let me know how you get on. Thanks.

      Liked by 1 person

  1. Thank you guys for mentioning (and liking!) my plugins. If you need standalone version, have a look at the LiveProfessor by Audiostrom software. It’s a VST host targeted at live performance. It’s free and it’s as close as it gets to standalone effects.

    Liked by 2 people

    • Your SoftAmp PSA is simply one of the best amp sims available out there. It puts a lot of the paid ones to shame and I’m not even exaggerating.

      The thing I like the most is how flexible the PSA is especially with the Speaker Sim knobs. I can completely change the tone of the sound to fit with any kind of music with just two knobs.

      It’s truly amazing. And I also have to say that the built in noise gate is absolutely amazing. The only other noise gate that I think is great (and free) is Vadim Taranov’s Noise Supression plugin.

      Liked by 1 person

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