HI ALL
I NEEDED INFO ABOUT PIONEER M-25 POWER AMP POWER TRANSISTORS
WHICH TRANSISTORS I CAN REPLACEMENTH TO MN25 AND MP25 POWER TRANSISTORS?:scratch2:
Thanks
Those are to-3 cased ring emitter transistors, with a very high MHZ specification - 45 to 60 mhz.
these STMicroelectronics transistors are probably the closest available anywhere:
2ST2121 PNP to-3 250V, 17/34A 250W 35-160hfe 25MHz $3.00
2ST5949 NPN to-3 250V, 17/34A 250W 35-160hfe 25MHz $3.00
mouser.com
511-2ST2121 PNP to-3 250V, 17/34A 250W 35-160hfe 25MHz $3.79
511-2ST5949 NPN to-3 250V, 17/34A 250W 35-160hfe 25MHz $5.14
digikey.com
497-8739-ND 2ST2121 PNP to-3 250V, 17/34A 250W 35-160hfe 25MHz $3.79
497-6953-ND 2ST5949 NPN to-3 250V, 17/34A 250W 35-160hfe 25MHz not available
these ON-Semi devices are much slower, at 4 mhz:
mouser.com
863-MJ21193G pnp to-3 250v 16/30A 250W 8-75hfe 4mhz $4.07
863-MJ21194G npn to-3 250v 16/30A 250W 8-75hfe 4mhz $4.07
digikey.com
MJ21193GOS-ND pnp to-3 250v 16/30A 250W 8-75hfe 4mhz $4.56
MJ21194GOS-ND npn to-3 250v 16/30A 250W 8-75hfe 4mhz $4.56
either way, you will need to scope it to check for stability with the substitution.
The driver stages (q10,q12 / q11,q13 in darlington configuration ) DO have 56 pf of negative feedback caps collector to base to control the high frequency gain, so if I were working on one, I would do one channel with the 4mhz transistors and the other with the 25 mhz transistors. Then test the daylights out of it on a scope, distortion analyzer and other instruments to figure out which to use.
as a guide, pioneer does spec the amp with a frequency response of 5hz to 200,000 hz +0 / -1 db (distortion and power for THIS not specified)
with 0.008% distortion at 60w (5 to 30,000 hz)
and 0.01% distortion at 120w into 8 ohms (0.02% into 4 ohms at 20,000 hz)