High voltage trannys
We use the big Toshiba exclusively (2SC5200/2SA1943) as they work so well, and do not fail - ever. We pay $0.90 for them each but we do buy large qtys. The Sankens in the MT200 packs are great but a pain in the rear to mount and are very expensive. Fairchild also make the 2SC5200/2SA1943 pairs and they work great. The Toshes are easy to clip mount or bar mount and they take up less real estate on the heatsink. Depending on your load the Toshes work fine to +/- 90v but you need lots of them if you want to drive 2 or 4 ohms. From my spreadsheets of SOA s at +/- 85v you need 5+5 Toshes for 4 ohms and 9+9 for 2 ohms (All temp derated to 80C). At 90 v you need 5+5 for 4 ohm and 10+10 for 2 ohm. However if you run them in a sries connected output stage, their Vceo is halved and you can use way less devices (yes double the drivers but they are cheap) So for a +/-90 v rail in a series output stage you need 4+4 for 4 ohm and 6+6 for 2 ohm (remember the 4+4 is actually 2+2 in series with 2+2 etc etc) Bipolars are current devices and their SOA is better if you keep their Vceo lower. Secondary breakdown is also less of a problem when running lower Vceo on BJTs. Of course a 2 stage class G circuit is the same as a 2 stage series output stage as far as SOA is concerned but you do need the extra supplies but you also use less heatsink. If you go to a triple stage class G (30-60-90) you do approach the efficiency of class D but not quite. When a class G amp is in it's outer rails it is NOT as efficient as a class D amp. We build both class G and class D amps. The parts count for a triple stage class G is high and the power supply costs go up. If efficiency is not an issue, then a series connected output stage is the best and sounds better than class G since you do not have the commutating diodes and their problems.
Hope this helps
Stephen Mantz Zed Audio Corporation CA
We use the big Toshiba exclusively (2SC5200/2SA1943) as they work so well, and do not fail - ever. We pay $0.90 for them each but we do buy large qtys. The Sankens in the MT200 packs are great but a pain in the rear to mount and are very expensive. Fairchild also make the 2SC5200/2SA1943 pairs and they work great. The Toshes are easy to clip mount or bar mount and they take up less real estate on the heatsink. Depending on your load the Toshes work fine to +/- 90v but you need lots of them if you want to drive 2 or 4 ohms. From my spreadsheets of SOA s at +/- 85v you need 5+5 Toshes for 4 ohms and 9+9 for 2 ohms (All temp derated to 80C). At 90 v you need 5+5 for 4 ohm and 10+10 for 2 ohm. However if you run them in a sries connected output stage, their Vceo is halved and you can use way less devices (yes double the drivers but they are cheap) So for a +/-90 v rail in a series output stage you need 4+4 for 4 ohm and 6+6 for 2 ohm (remember the 4+4 is actually 2+2 in series with 2+2 etc etc) Bipolars are current devices and their SOA is better if you keep their Vceo lower. Secondary breakdown is also less of a problem when running lower Vceo on BJTs. Of course a 2 stage class G circuit is the same as a 2 stage series output stage as far as SOA is concerned but you do need the extra supplies but you also use less heatsink. If you go to a triple stage class G (30-60-90) you do approach the efficiency of class D but not quite. When a class G amp is in it's outer rails it is NOT as efficient as a class D amp. We build both class G and class D amps. The parts count for a triple stage class G is high and the power supply costs go up. If efficiency is not an issue, then a series connected output stage is the best and sounds better than class G since you do not have the commutating diodes and their problems.
Hope this helps
Stephen Mantz Zed Audio Corporation CA
Also I almost always prefer Toshiba and Sanken devices, they sound good too.
The ON/ Motorola devices have huge dies and are kind of sluggish. Even look at the MJL1302 while it has fTof 30Mhz, it has a COB of 600pf!
The MJ21193/4 is slightly better with COB of 500pf while the 2sc5200 has COB of only 200pF.
The ON/ Motorola devices have huge dies and are kind of sluggish. Even look at the MJL1302 while it has fTof 30Mhz, it has a COB of 600pf!
The MJ21193/4 is slightly better with COB of 500pf while the 2sc5200 has COB of only 200pF.
K-amps said:www.matchakbob.com
they have the best prices i have seen for semi-conductors, forget MCM and Digikey...
have fun!
I got "this page cannot be displayed" error. any chance the server is down?
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