Model AB-Q-M125
The model AB-Q-M125 auto bias module is designed to fit the Bob Latino M125 mono block power amp.
It comes with a 1:1 isolation transformer so that the module can safely use one of the PA-060 power transformer 6.3VAC filament windings for its power.
You will need to let us know what brand of output coupling capacitors your M125 uses, as an additional two will be sent with the kit, plus two extra resistors as well.

The AB-Q-M125 dynamically controls the bias in four tubes.

The module automatically optimizes the bias settings and maintains a strict symmetry of currents through both tube branches in the output stage. It will also stop any DC current flowing through the output transformers, all with the minimum of current loading on the anode of a tube. 
DC current saturates an output transformer which results in increased low frequency distortions.

The bias level is kept at the preset value irrespective of the input signal.

- PCB dimensions are 100mm x 57mm / 4" x 2.25"
- Suitable for Cathode Feedback amps
- power supply requirement is 6.3VAC from one of the PA-060 filament windings
- negative DC bias supply between -55V to -90V


Price for one AB-Q-M125 module: US$75.00       in stock
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For shipping outside the lower 48, please contact us first, thank you.
For Canadian customers, please use the below PayPal button to purchase, as shipping of US$17.00 will be added to the unit price.