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Old 7th August 2004, 01:43 PM   #101
anatech is offline anatech  Canada
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Hi Lyra,
The higher collector voltage makes them more attractive for new design. This is not a factor in your case. The collector currents and power dissipation is the same in both so ....
At least they are not incompatible, you won't hurt anything. If your outputs were blown, I'd use the 2SA1302 or MJL1302 pair. Only because I stock them. There is no compeling reason to change them otherwise.
-Chris
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Old 8th August 2004, 02:52 AM   #102
Robin is offline Robin  United Kingdom
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The 2SC3281/1302 are not manufactured anymore by Toshiba and most of the devices on the market that are marked with these part numbers are dodgy pirates with sub standard silicon. Toshiba now market their equivalents and On Semi market their MJL alternatives which are identical. Just be careful if you buy parts these days that claim to be Toshiba.
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Old 28th August 2004, 05:45 AM   #103
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I am planning to make a class AB amp ,
Transformer 66v-o-66v ie DC will be +/- 93v
Power Output approx 450w 8E, 800w 4E , and 1500w 2E
The amp will rarely be used at 2E but I want to over kill ,

Will 8 pairs of 2SA1943/2SC5200 be ok ,
Drivers MJE15034/35 or 2SA1302/2SC3281
Filter caps 30,000MFD per rail

here the Toshiba drivers 2SA1302/2SC3281 are costing 50% more than MJE15034/35 which ones should I choose.

please advise and give your recomendations
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Old 28th August 2004, 07:11 AM   #104
Eva is offline Eva  Spain
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2SC3281/2SA1302 are also 15A 200V 20Mhz output transistors, they are not intended as drivers

Anyway, Toshiba discontinued them and replaced them by 2SC5200/2SA1943 [improved new versions] so if your amplifier circuit specifies C3281/A1302 as drivers, then you should also use C5200/A1943 instead

Please don't buy C3281/A1302 anymore, they are allways fakes. Currently it's obviouls that there are no remaining stocks of these devices. All the stocks existing when Toshiba stopped production [It was in 1999 I think] have been already sold and used

I bought some pairs of C3281/A1302 from different sources two years ago ang they were all fakes. Actually I got three different types of fakes with different cases, different markings and different die sizes!!! [Not to talk about different transistor parameters]

Currently there are probably a dozen or more counterfeit 'manufacturers' and each one is producing C3281/A1302 fakes in a particular flavor
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Old 28th August 2004, 01:25 PM   #105
K-amps is offline K-amps  United States
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I don't know the exact model but a Mark Levinson 4 series monoblock (rated at 300 8E, but actually does 500 8E, 9004E and 1.5kW 2E) uses 8 pairs of a Toshiba class TO-3PL devices.

It has 40mF per rail or 80,000uF in total with a 2372 VA toroid.

Your design seems similar to that in terms of power, I'd say as a rough estimate, you are on target.
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Old 28th August 2004, 01:56 PM   #106
OliverD is offline OliverD  Germany
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In turn the Accuphase M-8000, rated at 250W/8Ohm, uses 22 pairs of 150W output devices.

It depends on design philosophy, of course. 8 pairs are probably safe enough, although I used 12 pairs for my 300W/8Ohm power amps.
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Old 28th August 2004, 02:06 PM   #107
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Here I experiece the same thing. Drivers like MJE15030/31 has the same price as C5200 pairs.
What is so special about these drivers?
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Old 28th August 2004, 03:05 PM   #108
K-amps is offline K-amps  United States
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In greater than 4 pairs of outputs, I have seen manufacturers use power devices as drivers. Especially the C5200/A1943's because of low beta droop.

The 15030/31's are ok, but the 15034/35 are much better when mated to the MJL21193/4/5/6.

My experience.

Yes the 5200/1943 are not designed to be drivers but they perform well.
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Old 28th August 2004, 03:58 PM   #109
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To K - amps : Optimalision of driver depend on typical working current. Modern output devices have flat beta curve to the low current, but by low curren fall ft. I think, that from this case is better use as driver recomended drivers, 'cos they have optimalised ft by lower current.
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Old 28th August 2004, 04:24 PM   #110
MikeB is offline MikeB  Germany
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Yes, take a look into the datasheet from onsemi, these are very
excellent devices, at 100mA they still have ft of ~50mhz (typ).
Also they are very linear up to 1A. (both pnp & npn)
I once built a small poweramp using these as outputdevices.
They are really good ! Onsemi itself recommends them for amps up to 25watts.

BUT: Only use original onsemi devices. I had some from another noname
manufacturer, 2 seconds after powering up these exploded.

I was thinking of paralelling many of them, but this seemed crazy to me.
Here in germany they cost about €0,75. So for a not too hipower
amp they would be a real alternative...

Mike
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