diff --git a/src/lib/scoped-collection.hpp b/src/lib/scoped-collection.hpp
index f3a1e313f..b9174401b 100644
--- a/src/lib/scoped-collection.hpp
+++ b/src/lib/scoped-collection.hpp
@@ -404,7 +404,7 @@ namespace lib {
       /* === Element access and iteration === */
       
       I&
-      operator[] (size_t index)
+      operator[] (size_t index)  const
         {
           if (index < level_)
             return elements_[index].accessObj();
diff --git a/src/proc/asset/meta/time-grid.cpp b/src/proc/asset/meta/time-grid.cpp
index c46509787..89744eee0 100644
--- a/src/proc/asset/meta/time-grid.cpp
+++ b/src/proc/asset/meta/time-grid.cpp
@@ -75,6 +75,8 @@ namespace meta {
      * from the AssetManager, then attach a further
      * smart-ptr-to-Quantiser to that, which then can be
      * published via the \link advice.hpp "advice system"\endlink
+     * @note this allows to use a time grid just "by name",
+     *       without explicit dependance to the Session / Assets
      */
     inline PGrid
     publishWrapped (TimeGrid& newGrid)
diff --git a/src/proc/play/output-slot-connection.hpp b/src/proc/play/output-slot-connection.hpp
index 29e6bf8e4..71a830c7e 100644
--- a/src/proc/play/output-slot-connection.hpp
+++ b/src/proc/play/output-slot-connection.hpp
@@ -41,17 +41,19 @@
 
 #include "lib/error.hpp"
 #include "proc/play/output-slot.hpp"
+#include "lib/scoped-collection.hpp"
+#include "lib/iter-adapter-stl.hpp"
+#include "lib/iter-source.hpp"
 #include "lib/handle.hpp"
 //#include "lib/time/timevalue.hpp"
 //#include "proc/engine/buffer-provider.hpp"
 //#include "proc/play/timings.hpp"
-#include "lib/iter-source.hpp"
-#include "lib/iter-adapter-stl.hpp"
 //#include "lib/sync.hpp"
 
 #include <boost/noncopyable.hpp>
 #include <boost/scoped_ptr.hpp>
 //#include <string>
+#include <tr1/functional>
 #include <vector>
 //#include <tr1/memory>
 
@@ -65,7 +67,9 @@ namespace play {
 //using std::string;
   using lib::transform;
   using lib::iter_stl::eachElm;
-
+  
+  using std::tr1::placeholders::_1;
+  using std::tr1::bind;
   using std::vector;
 //using std::tr1::shared_ptr;
   using boost::scoped_ptr;
@@ -92,6 +96,7 @@ namespace play {
    *   implementation; yet it may as well be called from a separate
    *   service thread or some kind of callback.
    * @note the meaning of FrameID is implementation defined.
+   * @note typically the concrete connection is noncopyable
    */
   class OutputSlot::Connection
     {
@@ -121,6 +126,8 @@ namespace play {
     {
     public:
       virtual ~ConnectionState() { }
+      
+      virtual Connection& access (uint)  const    =0;
     };
   
   
@@ -143,11 +150,12 @@ namespace play {
   template<class CON>
   class ConnectionStateManager
     : public OutputSlot::ConnectionState
-    , public vector<CON>
     {
-      typedef vector<CON> Connections;
+      typedef lib::ScopedCollection<CON> Connections;
       typedef OutputSlot::OpenedSinks OpenedSinks;
       
+      Connections connections_;
+      
       
       /* == Allocation Interface == */
       
@@ -155,7 +163,7 @@ namespace play {
       getOpenedSinks()
         {
           REQUIRE (this->isActive());
-          return transform (eachElm(*this), connectOutputSink);
+          return transform (eachElm(connections_), connectOutputSink);
         }
       
       Timings
@@ -167,25 +175,29 @@ namespace play {
       bool
       isActive()  const
         {
-          return 0 < Connections::size();
+          return 0 < connections_.size();
+        }
+      
+      CON&
+      access (uint chanNr)  const
+        {
+          return connections_[chanNr];
         }
       
       
     protected: /* == API for OutputSlot-Impl == */
       
+      typedef typename Connections::ElementHolder& ConnectionStorage;
+      
       /** factory function to build the actual
        *  connection handling objects per channel */
-      virtual CON buildConnection()  =0;
-      
-      void
-      init (uint numChannels)
-        {
-          for (uint i=0; i<numChannels; ++i)
-            push_back(buildConnection());
-        }
+      virtual void buildConnection(ConnectionStorage)  =0;
       
       
-      ConnectionStateManager() { }
+      ConnectionStateManager(uint numChannels)
+        : connections_( numChannels
+                      , bind (&ConnectionStateManager::buildConnection, this, _1 ))
+        { }
       
     public:
       virtual
diff --git a/tests/components/proc/play/diagnostic-output-slot.hpp b/tests/components/proc/play/diagnostic-output-slot.hpp
index 9ab0f98a7..1554ce8cf 100644
--- a/tests/components/proc/play/diagnostic-output-slot.hpp
+++ b/tests/components/proc/play/diagnostic-output-slot.hpp
@@ -41,6 +41,8 @@
 #include "lib/time/timevalue.hpp"
 #include "lib/scoped-ptrvect.hpp"
 #include "lib/iter-source.hpp"
+#include "lib/advice.hpp"
+#include "lib/symbol.hpp"
 #include "lib/util.hpp"
 #include "proc/engine/testframe.hpp"
 //#include "lib/sync.hpp"
@@ -57,6 +59,8 @@ namespace proc {
 namespace play {
 
 //using std::string;
+  using lib::Symbol;
+  using util::unConst;
   using util::contains;
   using lib::time::FrameRate;
   using proc::asset::meta::PGrid;
@@ -70,6 +74,24 @@ namespace play {
   using std::tr1::shared_ptr;
 //using boost::scoped_ptr;
   
+  namespace { // diagnostics & internals....
+    
+    inline PGrid
+    getTestTimeGrid()
+    {
+      Symbol gridID("DiagnosticOutputSlot-buffer-grid");
+      lib::advice::Request<PGrid> query4grid(gridID) ;
+      PGrid testGrid25 = query4grid.getAdvice();
+      
+      if (!testGrid25)
+        testGrid25 = TimeGrid::build (gridID, FrameRate::PAL);
+      
+      ENSURE (testGrid25);
+      return testGrid25;
+    }
+  }
+  
+  
   /** 
    * Diagnostic output connection for a single channel,
    * allowing to track generated frames and verify 
@@ -77,17 +99,20 @@ namespace play {
    */
   class TrackingInMemoryBlockSequence
     : public OutputSlot::Connection
+    , boost::noncopyable
     {
       
       typedef std::tr1::unordered_set<FrameID> FrameTrackingInfo;
       
       
-      shared_ptr<TrackingHeapBlockProvider> buffProvider_;
+      TrackingHeapBlockProvider buffProvider_;
       BufferDescriptor bufferType_;
       
       FrameTrackingInfo frameTrackingIndex_;
       PGrid frameGrid_;
       
+      bool closed_;
+      
       
       BuffHandle
       trackFrame (FrameID frameNr, BuffHandle const& newBuffer)
@@ -115,8 +140,9 @@ namespace play {
       BuffHandle
       claimBufferFor(FrameID frameNr) 
         {
+          REQUIRE (!closed_);
           return trackFrame (frameNr,
-                             buffProvider_->lockBuffer (bufferType_));
+                             buffProvider_.lockBuffer (bufferType_));
         }
       
       
@@ -132,34 +158,38 @@ namespace play {
       void
       transfer (BuffHandle const& filledBuffer)
         {
+          REQUIRE (!closed_);
           pushout (filledBuffer);
         }
       
       void
       pushout (BuffHandle const& data4output)
         {
-          buffProvider_->emitBuffer   (data4output);
-          buffProvider_->releaseBuffer(data4output);
+          REQUIRE (!closed_);
+          buffProvider_.emitBuffer   (data4output);
+          buffProvider_.releaseBuffer(data4output);
         }
       
       void
       discard (BuffHandle const& superseededData)
         {
-          buffProvider_->releaseBuffer (superseededData);
+          REQUIRE (!closed_);
+          buffProvider_.releaseBuffer (superseededData);
         }
       
       void
       shutDown ()
         {
-          buffProvider_.reset();
+          closed_ = true;
         }
       
     public:
       TrackingInMemoryBlockSequence()
-        : buffProvider_(new TrackingHeapBlockProvider())
-        , bufferType_(buffProvider_->getDescriptor<TestFrame>())
+        : buffProvider_()
+        , bufferType_(buffProvider_.getDescriptor<TestFrame>())
         , frameTrackingIndex_()
-        , frameGrid_(TimeGrid::build ("DiagnosticOutputSlot-buffer-grid", FrameRate::PAL))  /////////////TODO should rather pass that in as part of a "timings" definition
+        , frameGrid_(getTestTimeGrid())                              /////////////TODO should rather pass that in as part of a "timings" definition
+        , closed_(false)
         {
           INFO (engine_dbg, "building in-memory diagnostic output sequence");
         }
@@ -173,22 +203,20 @@ namespace play {
       
       /* === Diagnostic API === */
       
-      TestFrame*
+      TestFrame const *
       accessEmittedFrame (uint frameNr)  const
         {
-          REQUIRE (buffProvider_);
-          if (frameNr <= buffProvider_->emittedCnt())
-            return &buffProvider_->accessAs<TestFrame> (frameNr);
+          if (frameNr <= buffProvider_.emittedCnt())
+            return & accessFrame(frameNr);
           else
             return 0;                                               ////////////////////////////////TICKET #856
         }
       
-      diagn::Block*
+      diagn::Block const *
       accessEmittedBuffer (uint bufferNr)  const
         {
-          REQUIRE (buffProvider_);
-          if (bufferNr <= buffProvider_->emittedCnt())
-            return & buffProvider_->access_emitted (bufferNr);
+          if (bufferNr <= buffProvider_.emittedCnt())
+            return & accessBlock(bufferNr);
           else
             return 0;
         }
@@ -196,9 +224,21 @@ namespace play {
       bool
       wasAllocated (uint frameNr)  const
         {
-          REQUIRE (buffProvider_);
           return contains (frameTrackingIndex_, frameNr);
         }
+      
+    private:
+      TestFrame const&
+      accessFrame (uint frameNr)  const
+        {
+          return unConst(this)->buffProvider_.accessAs<TestFrame> (frameNr);
+        }
+      
+      diagn::Block const&
+      accessBlock (uint bufferNr)  const
+        {
+          return unConst(this)->buffProvider_.access_emitted (bufferNr);
+        }
     };
   
   
@@ -210,17 +250,18 @@ namespace play {
   class SimulatedOutputSequences
     : public ConnectionStateManager<TrackingInMemoryBlockSequence>
     {
-      TrackingInMemoryBlockSequence
-      buildConnection()
+      typedef ConnectionStateManager<TrackingInMemoryBlockSequence> _Base;
+      
+      void
+      buildConnection(ConnectionStorage storage)
         {
-          return TrackingInMemoryBlockSequence();
+          storage.create<TrackingInMemoryBlockSequence>();
         }
       
     public:
       SimulatedOutputSequences (uint numChannels)
-        {
-          init (numChannels);
-        }
+        : _Base(numChannels)
+        { }
     };
   
     
@@ -276,7 +317,7 @@ namespace play {
         {
           REQUIRE (!isFree(), "diagnostic OutputSlot not (yet) connected");
           REQUIRE (channel <= getOutputChannelCount());
-          return static_cast<SimulatedOutputSequences&> (*state_).at(channel);
+          return static_cast<TrackingInMemoryBlockSequence&> (state_->access (channel));
         }
       
       
@@ -307,7 +348,7 @@ namespace play {
        * the emitted Data as a sequence of TestFrame objects.
        */
       class OutputFramesLog
-        : public lib::IterSource<TestFrame>
+        : public lib::IterSource<const TestFrame>
         , boost::noncopyable
         {
           TrackingInMemoryBlockSequence const& outSeq_;
@@ -366,8 +407,8 @@ namespace play {
       bool
       buffer_was_closed (uint channel, FrameID frame)
         {
-          diagn::Block* block = accessSequence(channel)
-                                  .accessEmittedBuffer(frame);
+          diagn::Block const *block = accessSequence(channel)
+                                        .accessEmittedBuffer(frame);
           return block
               && block->was_closed();
         }
@@ -376,8 +417,8 @@ namespace play {
       bool
       emitted (uint channel, FrameID frame)
         {
-          diagn::Block* block = accessSequence(channel)
-                                  .accessEmittedBuffer(frame);
+          diagn::Block const *block = accessSequence(channel)
+                                        .accessEmittedBuffer(frame);
           return block
               && block->was_used();
         }