diff --git a/src/devices/sound/msm5232.cpp b/src/devices/sound/msm5232.cpp
index 3d08f3582a8..0e8a8676f5e 100644
--- a/src/devices/sound/msm5232.cpp
+++ b/src/devices/sound/msm5232.cpp
@@ -199,31 +199,35 @@ static FILE *sample[9];
 
 
 /*
- * resistance values are guesswork, default capacity is mentioned in the datasheets
+ * Resistance values are guesswork, default capacity is mentioned in the datasheets
  *
- * charges external capacitor (default is 0.39uF) via R51
- * in approx. 5*1400 * 0.39e-6
+ * Two errors in the datasheet, one probable, one certain
+ * - it mentions 0.39uF caps, but most boards have 1uF caps and expect datasheet timings
  *
- * external capacitor is discharged through R52
- * in approx. 5*28750 * 0.39e-6
+ * - the 330ms timing of decay2 has been measured to be 250ms (which
+ *   also matches the duty cycle information for the rest of the table)
+ *
+ * In both cases it ends up with smaller resistor values, which are
+ * easier to do on-die.
+ *
+ * The timings are for a 90% charge/discharge of the external
+ * capacitor through three possible resistors, one for attack, two for
+ * decay.
+ *
+ * Expected timings are 2ms, 40ms and 250ms respectively with a 1uF
+ * capacitor.
+ *
+ * exp(-t/(r*c)) = (100% - 90%) => r = -r/(log(0.1)*c)
+ *
+ *   2ms ->    870 ohms
+ *  40ms ->  17400 ohms
+ * 250ms -> 101000 ohms
  */
 
 
-#define R51 1400    /* charge resistance */
-#define R52 28750   /* discharge resistance */
-
-#if 0
-/*
-    C24 = external capacity
-
-    osd_printf_debug("Time constant T=R*C =%f sec.\n",R51*C24);
-    osd_printf_debug("Cap fully charged after 5T=%f sec (sample=%f). Level=%f\n",(R51*C24)*5,(R51*C24)*5*sample_rate , VMAX*0.99326 );
-    osd_printf_debug("Cap charged after 5T=%f sec (sample=%f). Level=%20.16f\n",(R51*C24)*5,(R51*C24)*5*sample_rate ,
-           VMAX*(1.0-pow(2.718,-0.0748/(R51*C24))) );
-*/
-#endif
-
-
+static constexpr double R51 =    870;    /* attack resistance */
+static constexpr double R52 =  17400;    /* decay 1 resistance */
+static constexpr double R53 = 101000;    /* decay 2 resistance */
 
 
 void msm5232_device::init_tables()
@@ -244,31 +248,6 @@ void msm5232_device::init_tables()
 	m_noise_step = ((1<<STEP_SH)/128.0) * scale; /* step of the rng reg in 16.16 format */
 	/* logerror("noise step=%8x\n", m_noise_step); */
 
-#if 0
-{
-	/* rate tables (in milliseconds) */
-	static const int ATBL[8] = { 2,4,8,16, 32,64, 32,64};
-	static const int DTBL[16]= { 40,80,160,320, 640,1280, 640,1280,
-							333,500,1000,2000, 4000,8000, 4000,8000};
-	for (i=0; i<8; i++)
-	{
-		double clockscale = (double)m_chip_clock / 2119040.0;
-		double time = (ATBL[i] / 1000.0) / clockscale;  /* attack time in seconds */
-		m_ar_tbl[i] = 0.50 * ( (1.0/time) / (double)m_rate );
-		/* logerror("ATBL[%i] = %20.16f time = %f s\n",i, m_ar_tbl[i], time); */
-	}
-
-	for (i=0; i<16; i++)
-	{
-		double clockscale = (double)m_chip_clock / 2119040.0;
-		double time = (DTBL[i] / 1000.0) / clockscale;  /* decay time in seconds */
-		m_dr_tbl[i] = 0.50 * ( (1.0/time) / (double)m_rate );
-		/* logerror("DTBL[%i] = %20.16f time = %f s\n",i, m_dr_tbl[i], time); */
-	}
-}
-#endif
-
-
 	for (i=0; i<8; i++)
 	{
 		double clockscale = (double)m_chip_clock / 2119040.0;
@@ -278,8 +257,8 @@ void msm5232_device::init_tables()
 	for (i=0; i<8; i++)
 	{
 		double clockscale = (double)m_chip_clock / 2119040.0;
-		m_dr_tbl[i]   = (     (1<<i) / clockscale) * (double)R52;
-		m_dr_tbl[i+8] = (6.25*(1<<i) / clockscale) * (double)R52;
+		m_dr_tbl[i]   = ((1<<i) / clockscale) * (double)R52;
+		m_dr_tbl[i+8] = ((1<<i) / clockscale) * (double)R53;
 	}
 
 
diff --git a/src/mame/misc/ladyfrog.cpp b/src/mame/misc/ladyfrog.cpp
index d8feeb4b3ca..d39ec6a4ac5 100644
--- a/src/mame/misc/ladyfrog.cpp
+++ b/src/mame/misc/ladyfrog.cpp
@@ -324,7 +324,7 @@ void ladyfrog_state::ladyfrog(machine_config &config)
 	aysnd.add_route(ALL_OUTPUTS, "mono", 0.15);
 
 	MSM5232(config, m_msm, XTAL(8'000'000)/4);
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6);
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6);
 	m_msm->add_route(0, "mono", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "mono", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "mono", 1.0);   // pin 30  8'-1
diff --git a/src/mame/taito/bigevglf.cpp b/src/mame/taito/bigevglf.cpp
index c9b842c87fb..5d02f9679f2 100644
--- a/src/mame/taito/bigevglf.cpp
+++ b/src/mame/taito/bigevglf.cpp
@@ -595,7 +595,7 @@ void bigevglf_state::bigevglf(machine_config &config)
 	YM2149(config, "aysnd", 8_MHz_XTAL / 4).add_route(ALL_OUTPUTS, "mono", 0.15); // divider not verified
 
 	MSM5232(config, m_msm, 8_MHz_XTAL / 4); // divider not verified
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6); // 0.65 (???) uF capacitors
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); // 1 uF capacitors ?
 	m_msm->add_route(0, "mono", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "mono", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "mono", 1.0);   // pin 30  8'-1
diff --git a/src/mame/taito/buggychl.cpp b/src/mame/taito/buggychl.cpp
index b84e5b351cf..348babc24c7 100644
--- a/src/mame/taito/buggychl.cpp
+++ b/src/mame/taito/buggychl.cpp
@@ -892,7 +892,7 @@ void buggychl_state::buggychl(machine_config &config)
 	m_ay[1]->add_route(ALL_OUTPUTS, "mono", 0.50);
 
 	MSM5232(config, m_msm, 8_MHz_XTAL / 4);
-	m_msm->set_capacitors(0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6); // default 0.39 uF capacitors (not verified)
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); // default 1 uF capacitors (not verified)
 	m_msm->add_route(0, "mono", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "mono", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "mono", 1.0);   // pin 30  8'-1
diff --git a/src/mame/taito/msisaac.cpp b/src/mame/taito/msisaac.cpp
index 256c027b683..00af96f1d6d 100644
--- a/src/mame/taito/msisaac.cpp
+++ b/src/mame/taito/msisaac.cpp
@@ -815,7 +815,7 @@ void msisaac_state::msisaac(machine_config &config)
 	// port A/B likely to be TA7630 filters
 
 	MSM5232(config, m_msm, 2'000'000);
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6); // 0.65 (???) uF capacitors (match the sample, not verified)
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); // 1 uF capacitors (match the sample, not verified, standard)
 	m_msm->add_route(0, "mono", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "mono", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "mono", 1.0);   // pin 30  8'-1
diff --git a/src/mame/taito/nycaptor.cpp b/src/mame/taito/nycaptor.cpp
index 3e9a67904a8..2e5117d1c9c 100644
--- a/src/mame/taito/nycaptor.cpp
+++ b/src/mame/taito/nycaptor.cpp
@@ -782,7 +782,7 @@ void nycaptor_state::nycaptor(machine_config &config)
 	ay2.add_route(ALL_OUTPUTS, "speaker", 0.15);
 
 	MSM5232(config, m_msm, 2000000);
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6); /* 0.65 (???) uF capacitors (match the sample, not verified) */
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); /* 1 uF capacitors (match the sample, not verified, standard) */
 	m_msm->add_route(0, "speaker", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "speaker", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "speaker", 1.0);   // pin 30  8'-1
@@ -849,7 +849,7 @@ void nycaptor_state::cyclshtg(machine_config &config)
 	ay2.add_route(ALL_OUTPUTS, "speaker", 0.15);
 
 	MSM5232(config, m_msm, 2000000);
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6); /* 0.65 (???) uF capacitors (match the sample, not verified) */
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); /* 1 uF capacitors (match the sample, not verified, standard) */
 	m_msm->add_route(0, "speaker", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "speaker", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "speaker", 1.0);   // pin 30  8'-1
@@ -913,7 +913,7 @@ void nycaptor_state::bronx(machine_config &config)
 	ay2.add_route(ALL_OUTPUTS, "speaker", 0.15);
 
 	MSM5232(config, m_msm, 2000000);
-	m_msm->set_capacitors(0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6, 0.65e-6); /* 0.65 (???) uF capacitors (match the sample, not verified) */
+	m_msm->set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); /* 1 uF capacitors (match the sample, not verified, standard) */
 	m_msm->add_route(0, "speaker", 1.0);   // pin 28  2'-1
 	m_msm->add_route(1, "speaker", 1.0);   // pin 29  4'-1
 	m_msm->add_route(2, "speaker", 1.0);   // pin 30  8'-1
diff --git a/src/mame/taito/wyvernf0.cpp b/src/mame/taito/wyvernf0.cpp
index de1e5f5b9d8..17f8bc7c316 100644
--- a/src/mame/taito/wyvernf0.cpp
+++ b/src/mame/taito/wyvernf0.cpp
@@ -674,7 +674,7 @@ void wyvernf0_state::wyvernf0(machine_config &config)
 
 	// music
 	msm5232_device &msm(MSM5232(config, "msm", 2_MHz_XTAL)); // 2MHz - Clock verified
-	msm.set_capacitors(0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6, 0.39e-6); /* default 0.39 uF capacitors (not verified) */
+	msm.set_capacitors(1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6, 1e-6); /* default 1 uF capacitors (not verified) */
 	msm.add_route(0, "mono", 0.5);   // pin 28  2'-1
 	msm.add_route(1, "mono", 0.5);   // pin 29  4'-1
 	msm.add_route(2, "mono", 0.5);   // pin 30  8'-1