Good Output Units
OnSemi (Motorola's old Semiconductor Products Sector) makes very good MJL1302A/3281A output pairs, and they are rated at 200Vce.
Their new MJL4302A/4281A output pair are rated at 350Vce, and have the same Ft of 30MHz as the 1302A/3281As. Also, I concur with the many replies that the MJE15032-15033s are good drivers for the output section. For the inputs, I have used the MPS8099/8599 pair with very good results.
Steve
OnSemi (Motorola's old Semiconductor Products Sector) makes very good MJL1302A/3281A output pairs, and they are rated at 200Vce.
Their new MJL4302A/4281A output pair are rated at 350Vce, and have the same Ft of 30MHz as the 1302A/3281As. Also, I concur with the many replies that the MJE15032-15033s are good drivers for the output section. For the inputs, I have used the MPS8099/8599 pair with very good results.
Steve
There are four standout qualities you should seek in the output devices for an audio amplifier.
The first is linearity - beta should be flat, or near flat, from 100mA to at least 5 amps. It should be at least 50, moreover.
The second is speed; preferably 30MHz or even higher.
The third is good SOAR; as a rule this determines reliability into low impedance loads. The higher the maximum voltage rating of the device, GENERALLY the better the SOAR.
The fourth is purchase integrity; many are in fact fakes.
I use the Toshiba 2SC5200/2SA1943. These are available at reasonable cost from Toshiba agents, and come with factory certification and a mica washer kit. If you buy lots, you get them from the same batch, and their matching qualities are excellent.
Cheers,
Hugh
The first is linearity - beta should be flat, or near flat, from 100mA to at least 5 amps. It should be at least 50, moreover.
The second is speed; preferably 30MHz or even higher.
The third is good SOAR; as a rule this determines reliability into low impedance loads. The higher the maximum voltage rating of the device, GENERALLY the better the SOAR.
The fourth is purchase integrity; many are in fact fakes.
I use the Toshiba 2SC5200/2SA1943. These are available at reasonable cost from Toshiba agents, and come with factory certification and a mica washer kit. If you buy lots, you get them from the same batch, and their matching qualities are excellent.
Cheers,
Hugh
Thanks Masterterch.
MikeB: Just to clear things up about the OnSemi 1302As and 3281As, they are STILL manufactured. Also, I just went to their website, and they have added some new meduim-power TO-247 NPN and PNP audio output units to their lineup. Might be worth checking out.....
BTW, if anyone is interested, I have an extra rail of each of the TO-264 cased 1302As and 3281As. I will have to go down to the Vault to see exactly how many extras I have, since it has been a while since I've looked at them. I am trying to clean out some of my extra stuff, and these are the first things to go.
If so, email me at N8XO@aol.com and we can figure something out.
Rgds,
Steve
MikeB: Just to clear things up about the OnSemi 1302As and 3281As, they are STILL manufactured. Also, I just went to their website, and they have added some new meduim-power TO-247 NPN and PNP audio output units to their lineup. Might be worth checking out.....
BTW, if anyone is interested, I have an extra rail of each of the TO-264 cased 1302As and 3281As. I will have to go down to the Vault to see exactly how many extras I have, since it has been a while since I've looked at them. I am trying to clean out some of my extra stuff, and these are the first things to go.
If so, email me at N8XO@aol.com and we can figure something out.
Rgds,
Steve
MJW0281A/0302A
Yes, those are the ones. They must be new. I haven't tried them yet. Don't know if I'll have the chance to. New family, and that takes up all the time.
I'd say if you're going to do a medium power amp (50-100W) these might fit the bill, but for making the big boys, I would stick with the TO-264s.
Yes, those are the ones. They must be new. I haven't tried them yet. Don't know if I'll have the chance to. New family, and that takes up all the time.
I'd say if you're going to do a medium power amp (50-100W) these might fit the bill, but for making the big boys, I would stick with the TO-264s.
From Onsemi's web site:
MJW0281A/MJW0302A:
These complementary devices are lower power versions of the popular MJW3281A and MJW1302A audio output transistors. With superior gain linearity and safe operating area performance, these transistors are ideal for high fidelity audio amplifier output stages and other linear applications.
http://www.onsemi.com/pub/Collateral/MJW0281A DATASHEET.PDF
Basic characteristics are:
Vceo: 260 volts
Ic: 15 amps, 30 amps peak
Pd: 150 watts
Ft: 30 MHz
Cob: 400 pF
Read the documentation for full details.
I'm still curious about the ThermalTrak power transistors that have an integrated bias diode; Digikey now stocks them but they are a bit expensive.
http://www.onsemi.com/pub/Collateral/NJL3281D.PDF
For bipolar power transistors, OnSemi, Hitachi and Toshiba seem to have the most and best choices--that I'm aware of.
--Damon
MJW0281A/MJW0302A:
These complementary devices are lower power versions of the popular MJW3281A and MJW1302A audio output transistors. With superior gain linearity and safe operating area performance, these transistors are ideal for high fidelity audio amplifier output stages and other linear applications.
http://www.onsemi.com/pub/Collateral/MJW0281A DATASHEET.PDF
Basic characteristics are:
Vceo: 260 volts
Ic: 15 amps, 30 amps peak
Pd: 150 watts
Ft: 30 MHz
Cob: 400 pF
Read the documentation for full details.
I'm still curious about the ThermalTrak power transistors that have an integrated bias diode; Digikey now stocks them but they are a bit expensive.
http://www.onsemi.com/pub/Collateral/NJL3281D.PDF
For bipolar power transistors, OnSemi, Hitachi and Toshiba seem to have the most and best choices--that I'm aware of.
--Damon
schematic needed
Hi MikeB,
thanks for replying, any topology providing clear treble and containing few components somewhat similiar to p3a would work.
I have also seen ur symasym4 and 5 they seems to be very nice and i also know u r a great designer, but I m not confident abt building ur symasym as i dont have scope to finetune ur design and i m not that much experienced in amp testing and designing as my profession is different from my hobby(electronics).
regards
Hi MikeB,
thanks for replying, any topology providing clear treble and containing few components somewhat similiar to p3a would work.
I have also seen ur symasym4 and 5 they seems to be very nice and i also know u r a great designer, but I m not confident abt building ur symasym as i dont have scope to finetune ur design and i m not that much experienced in amp testing and designing as my profession is different from my hobby(electronics).
regards
raveenvijendren said:
These are the recommended output devices for the Leach amplifier, and work very well for general audio amplifier use. At one time they were second sourced and there may be counterfeit devices out there, but not nearly to the extent that certain other transistors have suffered.
I've been using MJ21193/94 in my Leach amplifiers, which are a bit more rugged and somewhat more linear.
In general, if the transistors have similar specifications to the
devices mentioned here and are designed for audio use, they'll work.
You'll have to observe the power limitations, and perhaps parallel output devices for more power (and lower distortion). Best to design with the limitations in mind and reduce rail voltages when in doubt.
Good Day,
You can say that again, about the counterfeit MJ15003/4 devices. It's really difficult to get the original Motorola devices. All they have are the ON semi and MOSPEC and Wingshing devices.
I think their handling capability is ~250W dissipation.
I see, so paralleling output devices results in more power and lower distortion. What about the amplifier's slew rate? Is that affected as well? The output pair I mentioned has an fT of 2 MHz.
Thank you for the information. Till later.
You can say that again, about the counterfeit MJ15003/4 devices. It's really difficult to get the original Motorola devices. All they have are the ON semi and MOSPEC and Wingshing devices.
I think their handling capability is ~250W dissipation.
I see, so paralleling output devices results in more power and lower distortion. What about the amplifier's slew rate? Is that affected as well? The output pair I mentioned has an fT of 2 MHz.
Thank you for the information. Till later.
OnSemi is a former division of Motorola and the current manufacturer
of the MJ15003/4 and other transistors I've mentioned; OnSemi is the
'real thing'. I don't know how good the others may be. You may
have to find out the hard way if you can't find a source for OnSemi.
Slew rate shouldn't be significantly affected by paralleling, at least
up to a point where the driver transistors may hit their limits in
a given design. I've never tried to work with more than three
paralleled sets of output transistors.
of the MJ15003/4 and other transistors I've mentioned; OnSemi is the
'real thing'. I don't know how good the others may be. You may
have to find out the hard way if you can't find a source for OnSemi.
Slew rate shouldn't be significantly affected by paralleling, at least
up to a point where the driver transistors may hit their limits in
a given design. I've never tried to work with more than three
paralleled sets of output transistors.
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