diff --git a/apps/basic/basic.asm b/apps/basic/basic.asm
index 807c265..158891c 100644
--- a/apps/basic/basic.asm
+++ b/apps/basic/basic.asm
@@ -4759,10 +4759,10 @@ CLPRINTHEADER:
 ; uses a,h,l
 ; -------------------------------------------------------
 CLLOADBLOCKS:
-        ld      a,b
+1$:     ld      a,b
         or      c
         ret     z
-1$:     push    bc
+        push    bc
         push    de
         call    CLREADBLOCK
         inc     hl              ; skip block type
diff --git a/bios.asm b/bios.asm
index dd2ccf7..434c328 100644
--- a/bios.asm
+++ b/bios.asm
@@ -144,6 +144,8 @@ init:
     call        ctc_uart_init
     ei
 
+    call        tape_init
+
     ; Print header message
     ld          hl,msg_header
     call        puts
diff --git a/scripts/encode.py b/scripts/encode.py
index be1cbe7..43a1363 100644
--- a/scripts/encode.py
+++ b/scripts/encode.py
@@ -46,7 +46,7 @@ class PulseWriter:
         self.space(0.1)
 
     def space(self, time: float) -> None:
-        self._level(0, int(time*self.sample_rate))
+        self._level(self.low, int(time*self.sample_rate))
 
     def _duration_samples(self, duration_us: float) -> int:
         sample_count = round(duration_us * self.sample_rate / 1_000_000)
diff --git a/tape.asm b/tape.asm
index 486c304..e440187 100644
--- a/tape.asm
+++ b/tape.asm
@@ -11,7 +11,9 @@ SHORT_MAX                   .equ TAPE_WORKSPACE + 002h ; byte
 LONG_AVG                    .equ TAPE_WORKSPACE + 003h ; byte
 LONG_MIN                    .equ TAPE_WORKSPACE + 004h ; byte
 LONG_MAX                    .equ TAPE_WORKSPACE + 005h ; byte
-BLOCK_BUFFER                .equ TAPE_WORKSPACE + 006h ; BLOCK_SIZE
+SHORT_OUT                   .equ TAPE_WORKSPACE + 006h ; byte
+LONG_OUT                    .equ TAPE_WORKSPACE + 007h ; byte
+BLOCK_BUFFER                .equ TAPE_WORKSPACE + 008h ; BLOCK_SIZE
 
 ; -------------------------------------------------------
 ; Error return callback macro
@@ -26,9 +28,17 @@ create_error_return MACRO &name, &code
     ENDM
 
 ; -------------------------------------------------------
+; -------------------------------------------------------
+tape_init:
+    ld          a,18
+    ld          (SHORT_OUT),a
+    ld          a,37
+    ld          (LONG_OUT),a
+    ret
+; -------------------------------------------------------
 ; Measure edge-to-edge pulse
 ; needs d (comparator state)
-; returns b (loop count)
+; returns b (loop count)80
 ; carry is timeout
 ; uses a
 ; loop is 36T extra 22T (0.6 loops)
@@ -567,14 +577,14 @@ get_buffer:
 ; needs d (output state)
 ; uses a
 ; before edge 20T
-; after edge 402T
+; after edge 408T
 ; -------------------------------------------------------
 gen_short:
     ld          a,d             ; 4T
     xor         1               ; 7T
     out         (TAPE_PORT),a   ; 12T
     ld          d,a             ; 4T
-    ld          a,18            ; 7T
+    ld          a,(SHORT_OUT)   ; 13T
 1$:                             ; loop: 21*a
     dec         a               ; 4T
     cp          0               ; 7T
@@ -586,14 +596,14 @@ gen_short:
 ; needs d (output state)
 ; uses a
 ; before edge 20T
-; after edge 801T
+; after edge 807T
 ; -------------------------------------------------------
 gen_long:
     ld          a,d             ; 4T
     xor         1               ; 7T
     out         (TAPE_PORT),a   ; 12T
     ld          d,a             ; 4T
-    ld          a,37            ; 7T
+    ld          a,(LONG_OUT)    ; 13T
 1$:                             ; loop: 21*a
     dec         a               ; 4T
     cp          0               ; 7T
diff --git a/tapes/test.wav b/tapes/test.wav
index f050e80..4fc5820 100644
Binary files a/tapes/test.wav and b/tapes/test.wav differ