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Transformers preparation

There are two transformers in the 1290 preamp.

Let's start with the input transformer.


Unscrew all screws from the VTB9045 and prepare the transformer PCB and the input transformer mounting bracket.


Pin 2 of the transformer should go into the hole circled with red.

Solder C1 to the bottom side of the PCB as shown on the photo.

Fix the input transformer with the screws (put the ground lug under one of the screws as shown). Solder the transformer to the PCB.


Solder pin 6 of the transformer to the ground lug with a thick wire.

Screw the mounting bracket to the opposite side of the transformer.

Now let's move on to the output transformer.


Solder wire links between pins 2 and 4, and between pins 6 and 7.


Solder zobel network (R64 and C9) between the pins 5 and 8 as shown.

Mount two 25mm standoffs to the output transformer mounting bracket as shown on the photo.
Mount the output transformer to the other sude of the bracket with a pair of M4 screws. Make sure to use lock washers.

Now we can move on to the Enclosure Preparation