Author Topic: Structural output transistors.  (Read 3520 times)

Offline teebee

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Structural output transistors.
« on: January 17, 2011, 12:41:09 PM »
I've used this amp almost every day for the past 10 years!

(1998 400A full steel chassis)

One type of problem-- and only twice.

I've noticed that the output transistors are the only thing supporting the weight of the power amp board. They are structural. This is common across several models.

HERE IT IS.

After the board traces and the leads on the output transistors (Sanken 2SC) fatigue from supporting the weight of the amp board and the rigors of the road, they break.

Because of this I suffered intermittent volume drops. The first occurrence was the fracture of a PCB trace. I fixed that with a reinforced reflow. FREE. The second occurrence was a fractured Output transistor-to-board lead. Big fat Sanken 2SC transistor: $12 at local electronics supply store.

Not bad considering how much gig time this head has seen!

This is a great and great sounding amplifier.

Cost of 10 years ownership and almost constant use: a mere $12.

WT-400+, 310UL2, Self made basses, Squier Jaguar, Mtd 535, F Bass BN5