diff --git a/src/ol/source/bingmapssource.js b/src/ol/source/bingmapssource.js
index f1eb3f415d..948f8537cb 100644
--- a/src/ol/source/bingmapssource.js
+++ b/src/ol/source/bingmapssource.js
@@ -4,7 +4,6 @@ goog.require('goog.Uri');
 goog.require('goog.array');
 goog.require('goog.asserts');
 goog.require('goog.net.Jsonp');
-goog.require('ol');
 goog.require('ol.Attribution');
 goog.require('ol.TileRange');
 goog.require('ol.TileUrlFunction');
@@ -49,15 +48,14 @@ ol.source.BingMaps = function(options) {
    */
   this.maxZoom_ = goog.isDef(options.maxZoom) ? options.maxZoom : -1;
 
-  var protocol = ol.IS_HTTPS ? 'https:' : 'http:';
   var uri = new goog.Uri(
-      protocol + '//dev.virtualearth.net/REST/v1/Imagery/Metadata/' +
+      'https://dev.virtualearth.net/REST/v1/Imagery/Metadata/' +
       options.imagerySet);
 
   var jsonp = new goog.net.Jsonp(uri, 'jsonp');
   jsonp.send({
     'include': 'ImageryProviders',
-    'uriScheme': ol.IS_HTTPS ? 'https' : 'http',
+    'uriScheme': 'https',
     'key': options.key
   }, goog.bind(this.handleImageryMetadataResponse, this));
 
@@ -93,7 +91,7 @@ ol.source.BingMaps.prototype.handleImageryMetadataResponse =
   }
 
   var brandLogoUri = response.brandLogoUri;
-  if (ol.IS_HTTPS && brandLogoUri.indexOf('https') == -1) {
+  if (brandLogoUri.indexOf('https') == -1) {
     brandLogoUri = brandLogoUri.replace('http', 'https');
   }
   //var copyright = response.copyright;  // FIXME do we need to display this?
diff --git a/src/ol/source/mapquestsource.js b/src/ol/source/mapquestsource.js
index d687fc5aae..3a56e3de8d 100644
--- a/src/ol/source/mapquestsource.js
+++ b/src/ol/source/mapquestsource.js
@@ -1,7 +1,6 @@
 goog.provide('ol.source.MapQuest');
 
 goog.require('goog.asserts');
-goog.require('ol');
 goog.require('ol.Attribution');
 goog.require('ol.source.OSM');
 goog.require('ol.source.XYZ');
@@ -32,9 +31,8 @@ ol.source.MapQuest = function(opt_options) {
    */
   this.layer_ = options.layer;
 
-  var protocol = ol.IS_HTTPS ? 'https:' : 'http:';
   var url = goog.isDef(options.url) ? options.url :
-      protocol + '//otile{1-4}-s.mqcdn.com/tiles/1.0.0/' +
+      'https://otile{1-4}-s.mqcdn.com/tiles/1.0.0/' +
       this.layer_ + '/{z}/{x}/{y}.jpg';
 
   goog.base(this, {
diff --git a/src/ol/source/osmsource.js b/src/ol/source/osmsource.js
index 7f992f136e..bd7ed7e6d3 100644
--- a/src/ol/source/osmsource.js
+++ b/src/ol/source/osmsource.js
@@ -1,6 +1,5 @@
 goog.provide('ol.source.OSM');
 
-goog.require('ol');
 goog.require('ol.Attribution');
 goog.require('ol.source.XYZ');
 
@@ -29,9 +28,8 @@ ol.source.OSM = function(opt_options) {
   var crossOrigin = goog.isDef(options.crossOrigin) ?
       options.crossOrigin : 'anonymous';
 
-  var protocol = ol.IS_HTTPS ? 'https:' : 'http:';
   var url = goog.isDef(options.url) ?
-      options.url : protocol + '//{a-c}.tile.openstreetmap.org/{z}/{x}/{y}.png';
+      options.url : 'https://{a-c}.tile.openstreetmap.org/{z}/{x}/{y}.png';
 
   goog.base(this, {
     attributions: attributions,
diff --git a/src/ol/source/stamensource.js b/src/ol/source/stamensource.js
index 2805a5fccd..ed34cb7988 100644
--- a/src/ol/source/stamensource.js
+++ b/src/ol/source/stamensource.js
@@ -1,7 +1,6 @@
 goog.provide('ol.source.Stamen');
 
 goog.require('goog.asserts');
-goog.require('ol');
 goog.require('ol.Attribution');
 goog.require('ol.source.OSM');
 goog.require('ol.source.XYZ');
@@ -99,11 +98,9 @@ ol.source.Stamen = function(options) {
       'known layer configured');
   var layerConfig = ol.source.StamenLayerConfig[options.layer];
 
-  var root = ol.IS_HTTPS ? 'https://stamen-tiles-{a-d}.a.ssl.fastly.net/' :
-      'http://{a-d}.tile.stamen.com/';
   var url = goog.isDef(options.url) ? options.url :
-      root + options.layer + '/{z}/{x}/{y}.' +
-      layerConfig.extension;
+      'https://stamen-tiles-{a-d}.a.ssl.fastly.net/' + options.layer +
+      '/{z}/{x}/{y}.' + layerConfig.extension;
 
   goog.base(this, {
     attributions: ol.source.Stamen.ATTRIBUTIONS,