Amplifier Project – Part 2

Sourcing Parts

The part sourcing turned out to be more difficult than originally thought.  The concept of harvesting components turned out to be a bit optimistic, there were but a handful of parts that can be used, mostly to do with the power supply.

All the resistors, caps and transistors were purchased on eBay (from US based companies so I could get them in a reasonable amount of time).  The transformer that was removed from the Integra receiver will work for this project, but I was hoping to find something smaller.  But a 50VAC center tap transformer is somewhat hard to find, and of the few that were located, the price and shipping was beyond what I felt was acceptable.  So the existing transformer will be used.

Testing The Transformer

The transformer is marked P/N NPT-1281D, and also indicates that it’s an Onkyo part… so that solves the mystery of who Integra is.

Transformer_41
The transformer was wired to AC using an old server power supply cable that was in the parts graveyard, soldered to the existing PCB.  A piece of cardboard was taped over the exposed connections so I didn’t inadvertently shock myself.

Transformer_1
Measured all voltages with reference to the center tap.  It’s a little less than what’s called out for on the schematic, but it will have to do.

Transformer_2 Transformer_3
Since the parts for the amp are in transit, well, most are anyway, and I think there’s enough parts to build the power supply, I’ll get started on that next.

 

 

 

1 comment for “Amplifier Project – Part 2

  1. December 25, 2013 at 2:56 pm

    My soldering skills are not that great (being that I never have tired it yet) one day I should give it a go.

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