Peavey Slave Amp ...

Motorola ( or "ON" ) select devices from regular stock to meet particular customer's requirements and supply them with a code number that is confidential.

With output transistors that are to be used in parallel sets, devices are selected that have near identical Base Emitter voltages for given collector currents. This is a parameter that varies quite independently from simple Beta.

I recall seeing a test rig and procedure described by PV that allows service techs to select output devices in this way.

Since they were released in 1977, MJ15024/5 devices have undergone several major revisions of the chip design and along with batch and sample to sample variations this renders older and newer examples incompatible for parallel operation.

Also and not least, these same devices are on the very top of the list for counterfeiters so you MUST know that the ones you buy are from authorised sources.

Farnell and RS Components are safe sources - almost no-one else is.

... Phil

"Arfa Daily"

That last one is plain crazy.

BTW:

PV released the 1.3K twenty years ago - the 4 digit date codes on the TO3 device will tell you when they were made.

Recent MJ15024/5s I have tested show slightly higher Vbe readings than old ones - so will draw less current when operating in parallel.

I only get worried if new devices draw more.

... Phil

my exploration of Peavey PV 2000, 2 x 1KW, 30Kg, 2001

Anybody know what the output transistors are in a Peavey PV-1.3K high power slave amp ? House codes 70484200 and 70474200

TIA

Arfa

We have stopped slavery about 60 years ago; get with the program. How would you like to be a slave?

Shaun

I have a 1.3K, it is usually on the floor. I was trying to think where I got the transistors. ? I have not tested it after the flood, but I hosed it out good ! I think I should check the connectors.

Greg

You are a slave, if you pay taxes you didn't vote for.