diff --git a/externals/tb/block_delay~/block_delay~.c b/externals/tb/block_delay~/block_delay~.c
index f5cfa4c828da2fa3c507dd893f27b716abda2a23..4d81060afc8f47e579f38d97df379f8691783902 100644
--- a/externals/tb/block_delay~/block_delay~.c
+++ b/externals/tb/block_delay~/block_delay~.c
@@ -95,5 +95,5 @@ void block_delay_tilde_setup(void)
 	block_delay_tilde_class = class_new(gensym("block_delay~"), (t_newmethod)block_delay_tilde_new, (t_method)block_delay_tilde_free,
 		sizeof(t_block_delay), 0, A_DEFFLOAT, 0);
 	class_addmethod(block_delay_tilde_class, nullfn, gensym("signal"), 0);
-	class_addmethod(block_delay_tilde_class, (t_method)block_delay_tilde_dsp, gensym("dsp"), 0);
+	class_addmethod(block_delay_tilde_class, (t_method)block_delay_tilde_dsp, gensym("dsp"), A_CANT, 0);
 }
diff --git a/externals/tb/erfc~/erfc~.c b/externals/tb/erfc~/erfc~.c
index d7b473754f5b39e82c85dd3c032fad6d7c06c2ba..82baa558a1e6b22c2527adaa70016b1b44a38726 100644
--- a/externals/tb/erfc~/erfc~.c
+++ b/externals/tb/erfc~/erfc~.c
@@ -60,5 +60,5 @@ void erfc_tilde_setup(void)
     erfc_class = class_new(gensym("erfc~"), (t_newmethod)erfc_new, 0,
         sizeof(t_erfc), 0, A_DEFFLOAT, 0);
     CLASS_MAINSIGNALIN(erfc_class, t_erfc, x_f);
-    class_addmethod(erfc_class, (t_method)erfc_dsp, gensym("dsp"), 0);
+    class_addmethod(erfc_class, (t_method)erfc_dsp, gensym("dsp"), A_CANT, 0);
 }
diff --git a/externals/tb/erf~/erf~.c b/externals/tb/erf~/erf~.c
index 2f59212e3a46cfd068ee96bb22ef317f47374955..db7e5d8af93eff230f2c154cfe1513ad437bdd19 100644
--- a/externals/tb/erf~/erf~.c
+++ b/externals/tb/erf~/erf~.c
@@ -60,5 +60,5 @@ void erf_tilde_setup(void)
     erf_class = class_new(gensym("erf~"), (t_newmethod)erf_new, 0,
         sizeof(t_erf), 0, A_DEFFLOAT, 0);
     CLASS_MAINSIGNALIN(erf_class, t_erf, x_f);
-    class_addmethod(erf_class, (t_method)erf_dsp, gensym("dsp"), 0);
+    class_addmethod(erf_class, (t_method)erf_dsp, gensym("dsp"), A_CANT, 0);
 }
diff --git a/externals/tb/volctl~/volctl~.c b/externals/tb/volctl~/volctl~.c
index 946beb38ea0b0b6b788f3104964aee52c1a7238c..0d846a1e4f36f1fc34c09160325e2a12d2e78397 100644
--- a/externals/tb/volctl~/volctl~.c
+++ b/externals/tb/volctl~/volctl~.c
@@ -363,7 +363,7 @@ void volctl_tilde_setup(void)
     volctl_class = class_new(gensym("volctl~"), (t_newmethod)volctl_new, 
 							 (t_method)volctl_free, sizeof(t_volctl), 0, A_GIMME, 0);
     CLASS_MAINSIGNALIN(volctl_class, t_volctl, x_f);
-    class_addmethod(volctl_class, (t_method)volctl_dsp, gensym("dsp"), 0);
+    class_addmethod(volctl_class, (t_method)volctl_dsp, gensym("dsp"), A_CANT, 0);
     class_addmethod(volctl_class, (t_method)volctl_set, gensym("f1"),A_FLOAT,0);
     class_settip(volctl_class,gensym("signal"));
 }