Revert "ZamTube: Simplify circuit with no Ci capacitor - no sound quality loss"

This reverts commit 77da69c220dbb7cdccf3b316e567e6ae69a0579d.

2 files changed, 21 insertions, 10 deletions

diff --git a/plugins/ZamTube/ZamTubePlugin.cpp b/plugins/ZamTube/ZamTubePlugin.cpp
index b47186b..b13fb4d 100644
--- a/plugins/ZamTube/ZamTubePlugin.cpp
+++ b/plugins/ZamTube/ZamTubePlugin.cpp
@@ -299,6 +299,7 @@ void ZamTubePlugin::activate()
 	
 	// Passive components
 	/* Original WDF preamp
+	ci[0] = 100e-9;
 	rg[0] = 20e+3;
 	rk[0] = 1e+3;
 	ck[0] = 10e-6;
@@ -309,6 +310,7 @@ void ZamTubePlugin::activate()
 	*/
 	
 	/* Matt's preamp */
+	ci[0] = 100e-9;
 	rg[0] = 1e-3;
 	rk[0] = 1200.; // 820 originally
 	ck[0] = 50e-6;
@@ -318,6 +320,7 @@ void ZamTubePlugin::activate()
 	ro[0] = 470e+3;
 
 	/* CLA's preamp
+	ci[0] = 1.0e-7;
 	rg[0] = 5.6e+3;
 	rk[0] = 1.5e+3;
 	ck[0] = 4.7e-6;
@@ -330,7 +333,7 @@ void ZamTubePlugin::activate()
 	int pre = 0;
 	float volumepot = 800e+3; // 100 good at low gain, 1000 good at high gain 
 	ckt.on = false;
-	ckt.updateRValues(ck[pre], co[pre], e[pre], er[pre], rg[pre], volumepot, rk[pre], 1e+3, ro[pre], Fs);
+	ckt.updateRValues(ci[pre], ck[pre], co[pre], e[pre], er[pre], rg[pre], volumepot, rk[pre], 1e+3, ro[pre], Fs);
 	ckt.warmup_tubes();
 
         fSamplingFreq = Fs;
diff --git a/plugins/ZamTube/wdfcircuits.h b/plugins/ZamTube/wdfcircuits.h
index 99c5eb7..3d1eb01 100644
--- a/plugins/ZamTube/wdfcircuits.h
+++ b/plugins/ZamTube/wdfcircuits.h
@@ -40,9 +40,10 @@ public:
 		E500E = 0.;
 	}
 
-	void updateRValues(Real C_Ck, Real C_Co, Real E_E500, Real R_E500, Real R_Rg, Real R_Ri, Real R_Rk, Real R_Vi, Real R_Ro, Real sampleRate) {
+	void updateRValues(Real C_Ci, Real C_Ck, Real C_Co, Real E_E500, Real R_E500, Real R_Rg, Real R_Ri, Real R_Rk, Real R_Vi, Real R_Ro, Real sampleRate) {
 
 		Real ViR = R_Vi;
+		Real CiR = 1.0 / (2.0*C_Ci*sampleRate);
 		Real RiR = R_Ri;
 		Real RgR = R_Rg;
 		Real RoR = R_Ro;
@@ -51,7 +52,10 @@ public:
 		Real E500R = R_E500;
 		E500E = E_E500;
 		Real CoR = 1.0 / (2.0*C_Co*sampleRate);
-		Real P0_1R = ViR;
+		Real S0_3R = (CiR + ViR);
+		S0_3Gamma1 = CiR/(CiR + ViR);
+		Assert(S0_3Gamma1 >= 0.0 && S0_3Gamma1 <= 1.0);
+		Real P0_1R = S0_3R;
 		Real P0_2R = RiR;
 		Real P0_3R = 1.0 /(1.0 / P0_1R + 1.0 / P0_2R);
 		P0_3Gamma1 = 1.0 / P0_1R/(1.0 / P0_1R + 1.0 / P0_2R);
@@ -103,14 +107,15 @@ public:
 		//S1_1SetA
 		//P0_3GetB
 		//S0_3GetB
-		//Real Cib = Cia;
+		Real Cib = Cia;
 		//S0_1SetA
 		//ViGetB
 		//S0_2SetA
+		Real S0_3b3 = -(Cib + ViE);
 		//P0_1SetA
 		//RiGetB
 		//P0_2SetA
-		Real P0_3b3 = -P0_3Gamma1*ViE;
+		Real P0_3b3 = -P0_3Gamma1*(-S0_3b3);
 		//S1_2SetA
 		Real S1_3b3 = -(P0_3b3);
 		//P1_3GetB
@@ -118,9 +123,9 @@ public:
 		//RkGetB
 		//P1_2SetA
 		//Call tube model
-		Real Vd = Vg-Vk;
-		Real Rd = (Vd > 0.) ? 2e+3 : 100e+9;
-		Vg = (S1_3b3);
+		Vg = -(S1_3b3);
+		Real Vd = Vk-Vg;
+		Real Rd = (Vd > 0.) ? 2e+2 : 10e+6;
 		Vk = -(P1_3b3 - Vg * S1_3Gamma1 / Rd);
 		Real b = t.compute(S2_3b3, S2_3Gamma1, Vg, Vk);
 		//Set As
@@ -141,11 +146,14 @@ public:
 		//RkSetA
 		//S1_3SetA
 		//RgSetA
+		Real S1_3b2 = Vg - S1_3Gamma1*(P0_3b3 + Vg);
 		//P0_3SetA
+		Real P0_3b1 = S1_3b2  - S0_3b3 - P0_3Gamma1*(-S0_3b3);
 		//S0_3SetA
-		//Cia = S0_3b1;
+		Real S0_3b1 = Cib - S0_3Gamma1*(Cib + ViE + P0_3b1);
+		Cia = S0_3b1;
 		//RiSetA
-		//printf("Vk=%f Vg=%f Vd=%f in=%f out=%f\n", Vk,Vg,Vd, ViE,Roa);
+		printf("Vk=%f Vg=%f Vd=%f in=%f out=%f\n", Vk,Vg,Vd, ViE,Roa);
 		return Roa;
 	}