the best just got better...

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mikek said:
These in my view, are currently the best all-round power BJT's on the planet:
:nod:

agreed

djk said:
Might be OK as a driver transistor.
No real output capability, only 100W safe area at 100V.
Speed drops like a rock above 4A or so.

hey those are power transistors not drivers !!!
if the safe operating area is 100V -1A or like u calculated 100W
it doesnt mean that if u use those as output transistors then your amp will be 100W !
 
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Re: Re: the best just got better...

djk said:
Might be OK as a driver transistor.

No real output capability, only 100W safe area at 100V.

Speed drops like a rock above 4A or so.


No...

sss said:


hey those are power transistors not drivers !!!
if the safe operating area is 100V -1A or like u calculated 100W
it doesnt mean that if u use those as output transistors then your amp will be 100W !


correct..
 
"I have used transistors with lower ft in some amps for high current and they do just fine. For example, the mj21193/21194 pair have a very respectable sound."

I would consider this new transistor a good driver for MJ21193/94 outputs. Above 4A the MJ21193/94 are faster, and have twice the safe area at 100V.

Introduction is pending, no samples or cost basis available.
 
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comparison

actually the new devices are demostrably superior to MJL21193/21194 in terms of gain-linearity...Ft..etc.

the newer devices can of course be used as drivers, but it would be more elegant to use Toshiba's 2SC4793/1837 pair, which are optimised for the purpose, and have Ft~100MHz.
 

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"...and i really cannot see how the MJL21194/93 pair can be said to be appreciably faster beyond 4A"


"...further, any differences in SOA are vanishingly negligible......."

Hey, I'm sorry you can't read the data sheets right.

Fig. 9 on the MJL4281 shows the unity gain bandwidth product to clearly be in the 2Mhz~3Mhz region at 5A. If I'm going to use this as a driver at 2A or less it is 40Mhz~50Mhz.

Fig.2 on the MJ21194 shows the gain bandwidth product at 5A to be almost 5Mhz.

Last time I checked, 5Mhz was faster than 3Mhz.

Fig.11 on the MJL4281 shows the safe area as being 100W at 100V

Fig. 13 on the MJ21194 shows the safe area as being 200W at 100V

The last time I checked, 200W was not a 'vanishing negligble' difference compared to 100W.

Pro amps with ±100V rails are not uncommon today. Peak currents at 2R are on the order of 40A. Without a tiered supply a popular amp uses 8 pair of MJ21193/94, about 5A per pair, another model from the same company with the same main rail voltages with a two tier supply only has 3 pair of 3281/1302, about 13A per pair.
 
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djk said:


Fig.11 on the MJL4281 shows the safe area as being 100W at 100V

Fig. 13 on the MJ21194 shows the safe area as being 200W at 100V

The last time I checked, 200W was not a 'vanishing negligble' difference compared to 100W.


If you tried to get the MJL21194'S to deliver 200W with 100v across them, they would promptly expire....see figure attached...
:rolleyes:
 

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