diff --git a/vector_quantize_pytorch/lookup_free_quantization.py b/vector_quantize_pytorch/lookup_free_quantization.py
index 3d0e1d2..c8ff2e8 100644
--- a/vector_quantize_pytorch/lookup_free_quantization.py
+++ b/vector_quantize_pytorch/lookup_free_quantization.py
@@ -161,6 +161,7 @@ def __init__(
 
         self.activation = straight_through_activation
 
+        assert not (scale_trick and spherical)
         self.scale_trick = scale_trick
 
         # whether to use BSQ (binary spherical quantization)