diff --git a/ddsp/core.py b/ddsp/core.py
index cc03afd..6b40721 100644
--- a/ddsp/core.py
+++ b/ddsp/core.py
@@ -62,7 +62,7 @@ def resample(x, factor: int):
 
 def upsample(signal, factor):
     signal = signal.permute(0, 2, 1)
-    signal = nn.functional.interpolate(signal, scale_factor=factor)
+    signal = nn.functional.interpolate(signal, size=signal.shape[-1] * factor)
     return signal.permute(0, 2, 1)