I'm running an Ibanez SR900 bass with active pickups to an Ampeg SVT-3 pro head to an Ampeg classic 4x10 cab.

When I turn the head on, it used to always take a second to warm up, then I've got great, loud sound.

Lately, I turn it on, and I can't hear it. I go through the troubleshooting guide and rule out my pickups and cable. I heard a tiny bit of volume, so I turned the master volume up. Nothing. I start playing slap bass, and all of a sudden, it comes on all the way. Then I'm able to turn the master down to normal and play normally until the next time I turn it on.

That rules out the speakers and speaker cable.

This happens 9 times out of 10 now, and it's starting to get annoying. Does anyone know what could cause this, or how to fix it?
i'd take it into the shop, because i wouldn't want to mess up something as good as that amp.
My name is Charlie.

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