Hi from a new Kid on the Block.

[Valvepower]

Hi from a new Kid on the Block.

I came across this forum whilst looking for the Motorola application note AN-483 on Darlington power amplifiers. I found reference to this note in an article in the Aug 1971 copy of Wireless World.

This has all come about because, I’m thinking of playing with a pair of ‘79 made HH TPA25-D power amplifiers, and going by the circuit layout & following the PCB it appears to use (Motorola) Darlington transistors marked with custom HH pt #’s. I’ve also noted there are a few other small similarities between the Motorola circuit in WW and the HH TPA.

The AN-483 thread is in the following post: Anybody have scan of AN-483B (Motorola)?

Hopefully I’ll be able to get in contact the members who said they have the application note.

And me – Well I’m an engineer employed in the UK electronics industry, but at heart I’m an audio DIYer. This comes from playing with discarded Quad II, Decca & Leak TL12+ gear when I was a Kid of thirteen back in 1973. My first job was building valve guitar amplifiers.

Terry.

[Cal Weldon]

Hello Terry and welcome to the forums.