diff --git a/pkgs/tools/graphics/welkin/default.nix b/pkgs/tools/graphics/welkin/default.nix
index 3d1a2aa5bdc..6e268ef5941 100644
--- a/pkgs/tools/graphics/welkin/default.nix
+++ b/pkgs/tools/graphics/welkin/default.nix
@@ -1,57 +1,35 @@
-x@{builderDefsPackage
-  , jre
-  , ...}:
-builderDefsPackage
-(a :
-let
-  helperArgNames = ["stdenv" "fetchurl" "builderDefsPackage"] ++
-    ["jre"];
+{ stdenv, fetchsvn, jre, makeWrapper }:
 
-  buildInputs = map (n: builtins.getAttr n x)
-    (builtins.attrNames (builtins.removeAttrs x helperArgNames));
-  sourceInfo = rec {
-    baseName="welkin";
-    version="1.1";
-    name="${baseName}-${version}";
-    url="http://simile.mit.edu/dist/welkin/${name}.tar.gz";
-    hash="0hr2xvfz887fdf2ysiqydv6m13gbdl5x0fh4960i655d5imvd5x0";
-  };
-in
-rec {
-  src = a.fetchurl {
-    url = sourceInfo.url;
-    sha256 = sourceInfo.hash;
+stdenv.mkDerivation rec {
+  name = "welkin-${version}";
+  version = "1.1";
+
+  src = fetchsvn {
+    url = "http://simile.mit.edu/repository/welkin";
+    rev = "9638";
+    sha256 = "1bqh3vam7y805xrmdw7k0ckcfwjg88wypxgv3njkkwyn7kxnfnqp";
   };
 
-  inherit (sourceInfo) name version;
-  inherit buildInputs;
+  sourceRoot = "welkin-r9638/tags/${version}";
 
-  /* doConfigure should be removed if not needed */
-  phaseNames = ["doDeploy" "createBin"];
+  buildInputs = [ jre makeWrapper ];
 
-  doDeploy = a.simplyShare "welkin";
-
-  createBin = a.fullDepEntry ''
-    mkdir -p "$out/bin"
-    echo "#! ${a.stdenv.shell}" > "$out/bin/welkin"
-    echo "export JAVA_HOME=${jre}" >> "$out/bin/welkin"
-    echo "\"$out/share/welkin/welkin.sh\" \"\$@\"" >> "$out/bin/welkin"
-    sed -e 's@[.]/lib/welkin[.]jar@"'"$out"'/share/welkin/lib/welkin.jar"@' -i "$out/share/welkin/welkin.sh"
-    chmod a+x "$out/bin/welkin"
-  '' ["minInit" "defEnsureDir"];
+  installPhase = ''
+    mkdir -p $out/{bin,share}
+    cp -R . $out/share
+    cp $out/share/welkin.sh $out/bin/welkin
+    sed -e 's@\./lib/welkin\.jar@'"$out"'/share/lib/welkin.jar@' -i $out/bin/welkin
+    wrapProgram $out/bin/welkin \
+      --set JAVA_HOME ${jre}
+    chmod a+x $out/bin/welkin
+  '';
 
   meta = {
     description = "An RDF visualizer";
-    maintainers = with a.lib.maintainers;
-    [
+    maintainers = with stdenv.lib.maintainers; [
       raskin
     ];
     hydraPlatforms = [];
-    license = a.lib.licenses.free;
+    license = stdenv.lib.licenses.free;
   };
-  passthru = {
-    updateInfo = {
-      downloadPage = "http://simile.mit.edu/dist/welkin/";
-    };
-  };
-}) x
+}