TBS – Tracking Bias Supply

CAD $35.00


The TBS Tracking Bias Supply kit provides an easy-to-install tracking bias supply for fixed-biased amplifiers. The proportion of bias voltage to tracked voltage is easily adjusted by changing one resistor on the TBS card, but this is only necessary for use with EL-84s.

Technical Details

The TBS kit includes a bias pot to set the bias voltage to the output stage. For individual bias pots per tube, simply parallel more bias pots and split their output feed.

TBS works best with a low-impedance raw bias supply. This can be a winding on the existing power transformer, or through use of our RBX Raw Bias Auxiliary Supply Kit. Also, see the article “Raw Bias Supply Modifications” on this site in the Tech Articles section.

Our books TUT2, TUT4 and TUT6 explain how to use regulated bias supplies and the special performance capabilities this can add to an amp.

If your stock amp is cathode-biased, add our RBX and TBS kits to have fixed-bias. You can still switch between cathode bias and fixed-bias using one of the methods outlined in the TUT-series. Use the TBS to “convert” an SV2 Power Scaling Kit for Cathode Bias into an SV1 Power Scaling Kit for Fixed Bias.

PCB dimensions: 1.15 x 0.8″, 29 x 20mm

Kit requires assembly.

Kit includes notes with installation tips + layout and schematic diagrams of the kit.

For more info, see “Selecting a Power Scaling Kit“.

See our Power Scaling FAQ.