diff --git a/libgrive/src/json/Val.cc b/libgrive/src/json/Val.cc
index 51ad62c..2facfff 100644
--- a/libgrive/src/json/Val.cc
+++ b/libgrive/src/json/Val.cc
@@ -123,7 +123,7 @@ std::string Val::Str() const
 
 Val::operator std::string() const
 {
-	return As<std::string>() ;
+	return Str();
 }
 
 int Val::Int() const
diff --git a/libgrive/src/json/Val.hh b/libgrive/src/json/Val.hh
index dfc2d33..4c8b9cc 100644
--- a/libgrive/src/json/Val.hh
+++ b/libgrive/src/json/Val.hh
@@ -194,35 +194,29 @@ Val& Val::Assign( const T& t )
 template <typename T>
 const T& Val::As() const
 {
-	try
-	{
-		const Impl<T> *impl = dynamic_cast<const Impl<T> *>( m_base.get() ) ;
-		return impl->val ;
-	}
-	catch ( std::exception& e )
+	const Impl<T> *impl = dynamic_cast<const Impl<T> *>( m_base.get() ) ;
+	if ( !impl )
 	{
 		TypeEnum dest = Type2Enum<T>::type ;
 		BOOST_THROW_EXCEPTION(
-			Error() << SrcType_(Type()) << DestType_(dest)
+			Error() << SrcType_( Type() ) << DestType_( dest )
 		) ;
 	}
+	return impl->val ;
 }
 
 template <typename T>
 T& Val::As()
 {
-	try
-	{
-		Impl<T> *impl = dynamic_cast<Impl<T> *>( m_base.get() ) ;
-		return impl->val ;
-	}
-	catch ( std::exception& e )
+	Impl<T> *impl = dynamic_cast<Impl<T> *>( m_base.get() ) ;
+	if ( !impl )
 	{
 		TypeEnum dest = Type2Enum<T>::type ;
 		BOOST_THROW_EXCEPTION(
-			Error() << SrcType_(Type()) << DestType_(dest)
+			Error() << SrcType_( Type() ) << DestType_( dest )
 		) ;
 	}
+	return impl->val ;
 }
 
 template <typename T>
diff --git a/libgrive/test/btest/ValTest.cc b/libgrive/test/btest/ValTest.cc
index 5514825..31c2cdb 100644
--- a/libgrive/test/btest/ValTest.cc
+++ b/libgrive/test/btest/ValTest.cc
@@ -19,6 +19,7 @@
 
 #include "json/Val.hh"
 #include <boost/test/unit_test.hpp>
+#include <iostream>
 
 using namespace gr ;
 
@@ -33,11 +34,11 @@ BOOST_FIXTURE_TEST_SUITE( ValTest, Fixture )
 
 BOOST_AUTO_TEST_CASE( TestSimpleTypes )
 {
-	Val null ;
-	BOOST_CHECK_EQUAL( null.Type(), Val::null_type ) ;
-	BOOST_CHECK( null.Is<void>() ) ;
+	BOOST_CHECK_EQUAL( Val::Null().Type(), Val::null_type ) ;
+	BOOST_CHECK( Val::Null().Is<void>() ) ;
 	
 	Val i( 100 ) ;
+	BOOST_CHECK_EQUAL( i.Str(), "100" );
 	BOOST_CHECK_EQUAL( i.As<long long>(), 100 ) ;
 	BOOST_CHECK_EQUAL( i.Type(), Val::int_type ) ;
 }