diff --git a/src/mame/sinclair/beta_m.cpp b/src/mame/sinclair/beta_m.cpp
index 09fec6be5c58c..0013cde772ae9 100644
--- a/src/mame/sinclair/beta_m.cpp
+++ b/src/mame/sinclair/beta_m.cpp
@@ -173,6 +173,14 @@ void beta_disk_device::data_w(uint8_t data)
 	}
 }
 
+void beta_disk_device::turbo_w(int state)
+{
+	if (m_betadisk_active == 1)
+	{
+		m_wd179x->set_clock_scale(1 << (state & 1));
+	}
+}
+
 void beta_disk_device::fdc_hld_w(int state)
 {
 	m_wd179x->set_force_ready(state); // HLD connected to RDY pin
@@ -206,6 +214,7 @@ void beta_disk_device::floppy_formats(format_registration &fr)
 static void beta_disk_floppies(device_slot_interface &device)
 {
 	device.option_add("525qd", FLOPPY_525_QD);
+	device.option_add("35hd", FLOPPY_35_HD);
 }
 
 
diff --git a/src/mame/sinclair/beta_m.h b/src/mame/sinclair/beta_m.h
index f809f12a0577b..2e37b22c73318 100644
--- a/src/mame/sinclair/beta_m.h
+++ b/src/mame/sinclair/beta_m.h
@@ -36,6 +36,7 @@ class beta_disk_device : public device_t
 	void track_w(uint8_t data);
 	void sector_w(uint8_t data);
 	void data_w(uint8_t data);
+	void turbo_w(int state);
 
 	int is_active();
 	void enable();
diff --git a/src/mame/sinclair/sprinter.cpp b/src/mame/sinclair/sprinter.cpp
index d1aeb1b08b252..e5d747559ba4c 100644
--- a/src/mame/sinclair/sprinter.cpp
+++ b/src/mame/sinclair/sprinter.cpp
@@ -686,6 +686,8 @@ void sprinter_state::dcp_w(offs_t offset, u8 data)
 		m_beta->param_w(data);
 		break;
 	case 0x16:
+	case 0x17:
+		m_beta->turbo_w(dcpp & 1);
 		if (data & 2)
 			m_beta->disable();
 		else