diff --git a/src/calibre/customize/profiles.py b/src/calibre/customize/profiles.py
index e281179565..5fb14988a5 100644
--- a/src/calibre/customize/profiles.py
+++ b/src/calibre/customize/profiles.py
@@ -426,7 +426,7 @@ class SonyReaderOutput(OutputProfile):
     dpi                       = 168.451
     fbase                     = 12
     fsizes                    = [7.5, 9, 10, 12, 15.5, 20, 22, 24]
-    unsupported_unicode_chars = [[u'\u2018',u'‘'], [u'\u2019',u'’'], [u'\u201a',u'‘'], [u'\u201b',u'’'], [u'\u201c',u'“'], [u'\u201d',u'”'], [u'\u201e',u'“'], [u'\u201f',u'”']]
+    unsupported_unicode_chars = [u'\u201f', u'\u201b']
 
 
 class KoboReaderOutput(OutputProfile):
diff --git a/src/calibre/ebooks/conversion/preprocess.py b/src/calibre/ebooks/conversion/preprocess.py
index 36221f486b..7f384a27bd 100644
--- a/src/calibre/ebooks/conversion/preprocess.py
+++ b/src/calibre/ebooks/conversion/preprocess.py
@@ -520,8 +520,12 @@ class HTMLPreProcessor(object):
             html = self.smarten_punctuation(html)
 
         unsupported_unicode_chars = self.extra_opts.output_profile.unsupported_unicode_chars
-        for [char, replacement] in unsupported_unicode_chars:
-            html = re.sub('%s' % char, replacement, html)
+        if unsupported_unicode_chars != []:
+            from calibre.ebooks.unidecode.unidecoder import Unidecoder
+            unidecoder = Unidecoder()
+            for char in unsupported_unicode_chars:
+                asciichar = unidecoder.decode(char)
+                html = re.sub('%s' % char, asciichar, html)
 
         return html