Popping noise at turn on

When first turning on my IRS2092S amp, it's fine. After turning off the amp and back on within 30 seconds or so (with volume up), there's a popping noise. This sometimes causes pulsating popping noises. When turned on with the volume down, there's no popping noise.
I do have a 100mfd non polarized capacitor from the output of the volume control to the input of the amp.
Any way to avoid the popping with the volume up?