Hello guys, working on a vintage Carver TFM 55 amplifier with a defective 2SC3281 output transistor. These apparently have been obsolete for some time now. Does anyone have a suggestion for a suitable replacement transistor? Thank you in advance for any help.
Hi cmrvi1,
MJL21195 / MJL21196. That's what I use in these.
TFM 55 amps have rails as high as +/- 125 VDC. The outputs should only see maybe 160 or so volts (125 VDC + the low rail voltage, I forget how much in that amp) as long as the commutators don't lock up, but if they do they can see the entire supply voltage.
MJL21195 / MJL21196. That's what I use in these.
TFM 55 amps have rails as high as +/- 125 VDC. The outputs should only see maybe 160 or so volts (125 VDC + the low rail voltage, I forget how much in that amp) as long as the commutators don't lock up, but if they do they can see the entire supply voltage.
On Semi
NJW3281G
NJW1302G
Available at Mouser_NJW3281 or Digikey_NJW3281G
Higher SOA with MJL package should be larger TO-264 package opposed to TO-3P
MJL3281AG
MJL1302AG
MJL3281AG
NJW3281G
NJW1302G
Available at Mouser_NJW3281 or Digikey_NJW3281G
Higher SOA with MJL package should be larger TO-264 package opposed to TO-3P
MJL3281AG
MJL1302AG
MJL3281AG
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The 2SC3281 was only rated at 200V Vceo. MJL2119x were 250. That provides more safety margin for commutator lock up, which does occur with those amps.
Today’s MJL3281 is rated at 260V. That was NOT the case when Motorola introduced it. It went from 200 to 230 to 260 over time. Will old ones block 260V? Probably. But using a part beyond rating, even if it will take it, is not something everyone will do.
Today’s MJL3281 is rated at 260V. That was NOT the case when Motorola introduced it. It went from 200 to 230 to 260 over time. Will old ones block 260V? Probably. But using a part beyond rating, even if it will take it, is not something everyone will do.