Hughes & Kettner Switchblade 50 Standard Retube Kit

Amps without the "TSC" circuit are adjustable bias and all you need to check and adjust the bias is a Multimeter and a bias probe, or our all-in-one octal "Pro One" bias probes (which reads plate voltage and plate current simultaneously). These are available under the "Related Products" tab.

You can use our Generic Bias Video for reference.

The video below explains the difference between bias probe types.