diff --git a/src/common/audio.ts b/src/common/audio.ts
index 700f0e45..398b699e 100644
--- a/src/common/audio.ts
+++ b/src/common/audio.ts
@@ -482,11 +482,11 @@ export var SampleAudio = function(clockfreq) {
   this.feedSample = function(value, count) {
     accum += value * count;
     sfrac += sinc * count;
-    while (sfrac >= 1) {
-      sfrac -= 1;
-      value *= sfrac;
-      this.addSingleSample(accum - value);
-      accum = value;
+    if (sfrac > 1) {
+      accum /= sfrac;
+      this.addSingleSample(accum * sinc);
+      sfrac -= Math.floor(sfrac);
+      accum *= sfrac;
     }
   }
   
diff --git a/src/machine/apple2.ts b/src/machine/apple2.ts
index fc25552a..14941313 100644
--- a/src/machine/apple2.ts
+++ b/src/machine/apple2.ts
@@ -4,7 +4,7 @@ import { Bus, BasicScanlineMachine, xorshift32, SavesState } from "../common/dev
 import { KeyFlags } from "../common/emu"; // TODO
 import { hex, lzgmini, stringToByteArray, RGBA, printFlags } from "../common/util";
 
-const cpuFrequency = 1023000;
+const cpuFrequency = 1022727;
 const cpuCyclesPerLine = 65; // approx: http://www.cs.columbia.edu/~sedwards/apple2fpga/
 const cpuCyclesPerFrame = 65*262;
 
diff --git a/src/worker/workermain.ts b/src/worker/workermain.ts
index d71e27e5..74075be8 100644
--- a/src/worker/workermain.ts
+++ b/src/worker/workermain.ts
@@ -2066,7 +2066,7 @@ function assembleNESASM(step:BuildStep) {
     asym = FS.readFile(sympath, {'encoding':'utf8'});
   } catch (e) {
     console.log(e);
-    errors.push({line:0,msg:"No symbol table generated, maybe segment overflow?"});
+    errors.push({line:0,msg:"No symbol table generated, maybe missing ENDM or segment overflow?"});
     return {errors:errors}
   }
   putWorkFile(binpath, aout);