ZamTube: Use two tube stages with tonestack in between

This gives the best of both combinations of tonestack position, and insane mode just changes the behaviour of the first tube stage.
zamaudio · Oct 21, 2023 · 462c82a · 462c82a
1 parent b8b2a42
commit 462c82a
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Showing 2 changed files with 13 additions and 9 deletions.
diff --git a/plugins/ZamTube/ZamTubePlugin.cpp b/plugins/ZamTube/ZamTubePlugin.cpp
@@ -334,7 +334,10 @@ void ZamTubePlugin::activate()
 	ro[0] = 100e+3;
 	*/
 
-	ckt.updateRValues(ci[0], ck[0], co[0], e[0], er[0], rg[0], 800e+3, rk[0], 1e+3, ro[0], Fs);
+	ckt[0].updateRValues(ci[0], ck[0], co[0], e[0], er[0], rg[0], 800e+3, rk[0], 1e+3, ro[0], Fs);
+	ckt[1].updateRValues(ci[0], ck[0], co[0], e[0], er[0], rg[0], 800e+3, rk[0], 1e+3, ro[0], Fs);
+	ckt[0].set_mode(ckt[0].TUBE_MODE_SIXTIES);
+	ckt[1].set_mode(ckt[1].TUBE_MODE_SIXTIES);
 
         fSamplingFreq = Fs;
 
@@ -412,7 +415,7 @@ void ZamTubePlugin::run(const float** inputs, float** outputs, uint32_t frames)
 	float scaled_drive = (tubedrive - 0.1) / 10.9;
 
 	float pregain = from_dB(scaled_drive * 20.);
-	float postgain = from_dB(mastergain - 6.) * 0.01;
+	float postgain = from_dB(mastergain - 48.);
 
 	if ((tonestackold != stack) || (bassold != bass) ||
 	    (middleold != middle) || (trebleold != treble)) {
@@ -425,21 +428,22 @@ void ZamTubePlugin::run(const float** inputs, float** outputs, uint32_t frames)
 
 	if (insaneold != (int)insane) {
 		insaneold = (int)insane;
-		ckt.set_mode(insane > 0.5 ? ckt.TUBE_MODE_GRIDLEAK : ckt.TUBE_MODE_SIXTIES);
-		ckt.updateRValues(ci[0], ck[0], co[0], e[0], er[0], rg[0], 800e+3, rk[0], 1e+3, ro[0], getSampleRate());
-		ZamTubePlugin::deactivate();
+		ckt[0].set_mode(insane > 0.5 ? ckt[0].TUBE_MODE_GRIDLEAK : ckt[0].TUBE_MODE_SIXTIES);
+		ckt[0].updateRValues(ci[0], ck[0], co[0], e[0], er[0], rg[0], 800e+3, rk[0], 1e+3, ro[0], getSampleRate());
 	}
 
 	for (uint32_t i = 0; i < frames; ++i) {
 
 		//Step 1: read input sample as voltage for the source
 		float in = inputs[0][i] * pregain;
 
-		tubeout = ckt.run(in) * postgain;
+		tubeout = ckt[0].run(in) * 0.01;
 
-		//Tone Stack (post tube)
+		//Tone Stack (sandwiched between two tube stages)
 		fRec0[0] = ((float)tubeout - (fSlow31 * (((fSlow30 * fRec0[1]) + (fSlow29 * fRec0[2])) + (fSlow27 * fRec0[3])))) + 1e-20f;
-		outputs[0][i] = sanitize_denormal((float)(fSlow31 * ((((fSlow46 * fRec0[0]) + (fSlow45 * fRec0[1])) + (fSlow43 * fRec0[2])) + (fSlow41 * fRec0[3]))));
+		tubeout = sanitize_denormal((float)(fSlow31 * ((((fSlow46 * fRec0[0]) + (fSlow45 * fRec0[1])) + (fSlow43 * fRec0[2])) + (fSlow41 * fRec0[3]))));
+
+		outputs[0][i] = ckt[1].run(tubeout) * postgain;
 
 		// update filter states
 		fRec0[3] = fRec0[2];

diff --git a/plugins/ZamTube/ZamTubePlugin.hpp b/plugins/ZamTube/ZamTubePlugin.hpp
@@ -47,7 +47,7 @@ typedef long double quad;
 class ZamTubePlugin : public Plugin
 {
 public:
-	TubeStageCircuit ckt;
+	TubeStageCircuit ckt[2];
 	T ci[2];
 	T ck[2];
 	T co[2];