Motorola transistors

My amps currently have 15003/15004 transistor set. I've read that the 15022/15023 transistors are faster than the 15003/15004, has anyone tried the newer ones or can tell if changing them will have a noticeable effect on the amplifiers?

Motorola Semiconductor was split into two companies a few years back. Freescale Semiconductor designs/builds/markets the more complex semiconductors such as microprocessors, DSP's sensors, RF circuits etc. I work for Freescale.

ON Semiconductor sells the discrete product line.
The actual part #'s are MJ15......
The MJ15003/4 are 20A, 150V, 25 min hfe, Ft = 2Mhz
The MJ15022/3 are 16A, 200V, 15 min hfe, Ft = 4 Mhz

It will depend on the actual amp design as to whether or not this swap will even work, much less give an improvement.
Thanks Cford. I had read that it was a direct swap but what you say makes me question it. I think I'll stick with what I got until it blows and based on the reputation of these power transistors, it should be a long long time...
. . . and actually newer, better, and more closely matched out of the box than the 15022/15023 is the ON Semi MJ21195 (PNP) and MJ21196 (NPN). Currently, I'm in the middle of totally rebuilding a Threshold Stasis 2 using these.

Lot's of good info in this area at
. . . but you probabaly won't hear any big difference by changing output devices from one revision to another. The main thing is to make sure that the bias is correctly.