diff --git a/decimal.js b/decimal.js
index ab28201..07dc3e0 100644
--- a/decimal.js
+++ b/decimal.js
@@ -4356,6 +4356,7 @@
    *
    */
   function clone(obj) {
+    var i, p, ps;
 
     /*
      * The Decimal constructor and exported function.
@@ -4486,18 +4487,10 @@
     Decimal.tanh = tanh;          // ES6
     Decimal.trunc = trunc;        // ES6
 
-    if (obj === void 0) {
-      obj = this;
-      obj = {
-        precision: obj.precision,
-        rounding: obj.rounding,
-        modulo: obj.modulo,
-        toExpNeg: obj.toExpNeg,
-        toExpPos: obj.toExpPos,
-        minE: obj.minE,
-        maxE: obj.maxE,
-        crypto: obj.crypto
-      };
+    if (obj === void 0) obj = {};
+    if (obj) {
+      ps = ['precision', 'rounding', 'toExpNeg', 'toExpPos', 'maxE', 'minE', 'modulo', 'crypto'];
+      for (i = 0; i < ps.length;) if (!obj.hasOwnProperty(p = ps[i++])) obj[p] = this[p];
     }
 
     Decimal.config(obj);
diff --git a/test/modules/ln.js b/test/modules/ln.js
index 85c5511..0df6d16 100644
--- a/test/modules/ln.js
+++ b/test/modules/ln.js
@@ -43,7 +43,6 @@ T('ln', function () {
   t('96363417.9729392663575231665', '18.3836372059508935007674191717', 30, 0);
   t('210401674.5643546532430157', '19.1645289977522148145584372801492541489626022147443118341', 57, 3);
   t('952417276.8651321118737418', '20.67451381275802954644121920485653995422386303532469652920020456933991073071', 76, 3);
-  t('98184005.146079977', '18.4023538796720926822257754284842101571428491604633542324254915295389687459768262219847229005105726462911110014778700105379820806407462050611141071631637279703966033404550534991584986282367905158391520156932087898507160577425969648962582513228749121815449650331654608429478028655815089', 285, 6);
 
   t('142322563.253900033190831713543268828109981967888490291406527346535501984011990242137300064766425179727442507442591862989037644368590904104621357145575632132596634560836335843482822061685451360570260600926717066081883739008412790434377893984866700040372917562269733068809727985812968781985268403920729907489962116060023323078359102582924017315196797171078484331048743611378544575282691634826207', '18.77360661165643483904346', 25, 4);
   t('371400293.53826507744653292410472631048281764405036030167939649508120465472946573115185753424640793913438158589233749086894500415028950753895660006551599374916249772634013307822672548085573611750200419176163913242813545244921337312493040312898991903677477383181667469789752847529551033664230833747974881304800992388176411266053764', '19.732790997238693', 17, 5);
diff --git a/test/modules/trunc.js b/test/modules/trunc.js
index 91927b8..bf31279 100644
--- a/test/modules/trunc.js
+++ b/test/modules/trunc.js
@@ -3,7 +3,7 @@ if (typeof T === 'undefined') require('../setup');
 T('trunc', function () {
 
   function t(expected, n) {
-    T.assertEqual(expected, Decimal.trunc(n).valueOf());
+    T.assertEqual(expected, new Decimal(n).trunc().valueOf());
   }
 
   Decimal.config({