RMI-FC100, a single stage audio power amplifier

[AndrewT]

Have you looked at the PCB layout?
What is located where those black mysteries reside?
A pair of To126 transistors.
Does that give you a clue rather than reading.

[housing]

Originally Posted by AndrewT

Have you looked at the PCB layout?
What is located where those black mysteries reside?
A pair of To126 transistors.
Does that give you a clue rather than reading.

You better look at the picture more carefully. Are the 2SC3423's that huge?

[zdr]

Now, I have to ask a stoopid question: what is the purpose of heatshrinking together a LED and a single transistor?

[AndrewT]

is there anybody out there that reads the thread and what Roender has to tell us?

[AndrewT]

Originally Posted by housing

Are the 2SC3423's that huge?

look at the datasheet. It tells you that 2sc3423 are To126.

[housing]

Originally Posted by AndrewT

look at the datasheet. It tells you that 2sc3423 are To126.

I have partially populated PCBs, and you don't have to tell me that 2SC3423's are TO126. I'm using those that I bought in the 1990's.

[zdr]

Originally Posted by housing

No, I mean this black thing circled in red.

It does look like four transistors in a hug with heatsink.

[housing]

Andrew,

Did I only read?

[zdr]

Originally Posted by AndrewT

is there anybody out there that reads the thread and what Roender has to tell us?

I did read it once few months back, but due to the noise posts like this, it's kinda difficult to trace back what you need

[Sheldon]

Originally Posted by housing

No, I mean this black thing circled in red.

Just there to thermally couple the transistors and the diode. It's a refinement more than a necessity, as they are touching anyway. The thermal time constants are fairly large compared to music signals, so they just keep bias drift lower. You can use heatshrink tubing there, as the total dissipation is low.

Sheldon