There are two transformers in the 1290 preamp.
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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. |
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Solder C1 to the bottom side of the PCB as shown on the photo. |
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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. |
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Screw the mounting bracket to the opposite side of the transformer. |
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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. |
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| Mount two 25mm standoffs to the output transformer mounting bracket as shown on the photo. |
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| Mount the output transformer to the other sude of the bracket with a pair of M4 screws. Make sure to use lock washers. |
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Now we can move on to the Enclosure Preparation