diff --git a/Tone/instrument/PolySynth.test.ts b/Tone/instrument/PolySynth.test.ts
index 05cc63c8..a9013720 100644
--- a/Tone/instrument/PolySynth.test.ts
+++ b/Tone/instrument/PolySynth.test.ts
@@ -278,6 +278,13 @@ describe("PolySynth", () => {
 			polySynth.dispose();
 		});
 
+		it("throws an error when used without a monophonic synth", () => {
+			expect(() => {
+				// @ts-ignore
+				new PolySynth(PluckSynth);
+			}).throws(Error)
+		});
+
 		it("can pass in the volume", () => {
 			const polySynth = new PolySynth({
 				volume: -12,
diff --git a/Tone/instrument/PolySynth.ts b/Tone/instrument/PolySynth.ts
index 26780486..90229b40 100644
--- a/Tone/instrument/PolySynth.ts
+++ b/Tone/instrument/PolySynth.ts
@@ -176,6 +176,7 @@ export class PolySynth<Voice extends Monophonic<any> = Synth> extends Instrument
 				context: this.context,
 				onsilence: this._makeVoiceAvailable.bind(this),
 			}));
+			assert(voice instanceof Monophonic, "Voice must extend Monophonic class");
 			voice.connect(this.output);
 			this._voices.push(voice);
 			return voice;