diff --git a/AsyncRattus.cabal b/AsyncRattus.cabal
--- a/AsyncRattus.cabal
+++ b/AsyncRattus.cabal
@@ -1,6 +1,6 @@
 cabal-version:       1.18
 name:                AsyncRattus
-version:             0.1.0.2
+version:             0.1.0.3
 category:            FRP
 synopsis:            An asynchronous modal FRP language
 description:
diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,10 @@
-# 0.1.0.1
+# 0.1.0.3
+
+Fix concurrency bug in the interaction of output and input channels.
+This occurred when using mkInput (and thus also filter functions on
+signals).
+
+# 0.1.0.2
 
 Make Integer and Text stable types
 
diff --git a/src/AsyncRattus/Channels.hs b/src/AsyncRattus/Channels.hs
--- a/src/AsyncRattus/Channels.hs
+++ b/src/AsyncRattus/Channels.hs
@@ -25,7 +25,7 @@
 
 import AsyncRattus.Plugin.Annotation
 import AsyncRattus.Strict
-import Control.Concurrent.MVar
+import Control.Concurrent.Chan
 import Control.Monad
 import System.IO.Unsafe
 import Data.IORef
@@ -67,8 +67,8 @@
 
 
 {-# NOINLINE input #-}
-input :: MVar InputValue
-input = unsafePerformIO newEmptyMVar
+input :: Chan InputValue
+input = unsafePerformIO newChan
 
 data OutputChannel where
   OutputChannel :: Producer p a => !(O p) -> !(a -> IO ()) -> OutputChannel
@@ -90,7 +90,7 @@
 getInput :: IO (Box (O a) :* (a -> IO ()))
 getInput = do ch <- atomicModifyIORef nextFreshChannel (\ x -> (x - 1, x))
               return ((box (Delay (singletonClock ch) (\ (InputValue _ v) -> unsafeCoerce v)))
-                       :* \ x -> putMVar input (InputValue ch x))
+                       :* \ x -> writeChan input (InputValue ch x))
 
 setOutput' :: Producer p a => (a -> IO ()) -> O p -> IO ()
 setOutput' cb !sig = do
@@ -98,7 +98,7 @@
   let upd Nothing = (Just (ref :! Nil),())
       upd (Just ls) = (Just (ref :! ls),())
   let upd' ch Nothing = do
-        forkIO (threadDelay ch >> putMVar input (InputValue ch ()))
+        forkIO (threadDelay ch >> writeChan input (InputValue ch ()))
         return (Just (ref :! Nil),())
       upd' _ (Just ls) = return (Just (ref :! ls),())
   let run pre ch =
@@ -152,7 +152,7 @@
 {-# ANN eventLoop NotAsyncRattus #-}
 
 eventLoop :: IO ()
-eventLoop = do inp@(InputValue ch _) <- takeMVar input
+eventLoop = do inp@(InputValue ch _) <- readChan input
                res <- H.lookup output ch
                case res of
                  Nothing -> return ()