diff --git a/src/emu/sound/nes_apu.c b/src/emu/sound/nes_apu.c
index c645537109a..88d951a6256 100644
--- a/src/emu/sound/nes_apu.c
+++ b/src/emu/sound/nes_apu.c
@@ -377,7 +377,7 @@ static int8 apu_dpcm(struct nesapu_info *info, dpcm_t *chan)
          bit_pos = 7 - (chan->bits_left & 7);
          if (7 == bit_pos)
          {
-            chan->cur_byte = chan->cpu_mem[chan->address];
+            chan->cur_byte = program_read_byte(chan->address);
             chan->address++;
             chan->length--;
          }
@@ -600,6 +600,7 @@ INLINE void apu_update(struct nesapu_info *info, stream_sample_t *buffer16, int
 {
    int accum;
 
+	cpuintrf_push_context( info->APU.dpcm.cpu_num );
    while (samples--)
    {
       accum = apu_square(info, &info->APU.squ[0]);
@@ -616,6 +617,7 @@ INLINE void apu_update(struct nesapu_info *info, stream_sample_t *buffer16, int
 
       *(buffer16++)=accum<<8;
    }
+	cpuintrf_pop_context();
 }
 
 /* READ VALUES FROM REGISTERS */
@@ -691,7 +693,7 @@ static void *nesapu_start(const char *tag, int sndindex, int clock, const void *
 	info->buffer_size+=info->samps_per_sync;
 
 	/* Initialize individual chips */
-	(info->APU.dpcm).cpu_mem=memory_region(Machine, intf->region);
+	(info->APU.dpcm).cpu_num= mame_find_cpu_index(Machine, intf->cpu_tag);
 
 	info->stream = stream_create(0, 1, rate, info, nes_psg_update_sound);
 
diff --git a/src/emu/sound/nes_apu.h b/src/emu/sound/nes_apu.h
index 0ad08932d48..115c3fe873b 100644
--- a/src/emu/sound/nes_apu.h
+++ b/src/emu/sound/nes_apu.h
@@ -39,7 +39,7 @@
 typedef struct _nes_interface nes_interface;
 struct _nes_interface
 {
-	const char *region;  /* DMC regions */
+	const char *cpu_tag;  /* CPU tag */
 };
 
 READ8_HANDLER( nes_psg_0_r );
diff --git a/src/emu/sound/nes_defs.h b/src/emu/sound/nes_defs.h
index 4673d9af0f4..e8de4eb4537 100644
--- a/src/emu/sound/nes_defs.h
+++ b/src/emu/sound/nes_defs.h
@@ -137,7 +137,7 @@ typedef struct dpcm_s
    uint8 cur_byte;
    boolean enabled;
    boolean irq_occurred;
-   uint8 *cpu_mem;
+   int cpu_num;
    signed char vol;
 } dpcm_t;