diff --git a/externals/mrpeach/rojo~/rojo~.c b/externals/mrpeach/rojo~/rojo~.c
index 13c2f6b66d5dbb56ed736643b289e484c8956142..96db57dbb3ea8d08d8c020610b762aaafbfe8827 100644
--- a/externals/mrpeach/rojo~/rojo~.c
+++ b/externals/mrpeach/rojo~/rojo~.c
@@ -65,7 +65,7 @@ void rojo_tilde_setup(void)
 {
     rojo_class = class_new(gensym("rojo~"), (t_newmethod)rojo_new, 0,
         sizeof(t_rojo), CLASS_NOINLET, A_GIMME, 0);
-    class_addmethod(rojo_class, (t_method)rojo_dsp, gensym("dsp"), 0);
+    class_addmethod(rojo_class, (t_method)rojo_dsp, gensym("dsp"), A_CANT, 0);
 }
 /*------------------------------------------------------------------*/
 static t_int *perform0(t_int *w)