Wow, those are old
Be careful with the voltages, BC249C is probably the only safe one to use because of this (35v rails give 70v peak to peak). Can you get anything a bit newer, the gain seems quite low also compared to the usual P3a candidates.
btw I am new to this hobby too so I can only point out what's obvious to me..........not always a lot
Cheers
Paul
Be careful with the voltages, BC249C is probably the only safe one to use because of this (35v rails give 70v peak to peak). Can you get anything a bit newer, the gain seems quite low also compared to the usual P3a candidates.
btw I am new to this hobby too so I can only point out what's obvious to me..........not always a lot
Cheers
Paul
From the standpoint of SOA it looks like you could but only the C version.
The ability to dissapate heat is not quite as good as the 2sa1302/2sc3281 plus the package design is not the best for mounting to a heatsink. I would suggest you use a clip or a bar across the encapsulated part of the package to hold it to the heatsink rather than just a bolt through the hole on the upper part of the tab.
Finally, I wish the datasheet showed fT since this bears some relationship to the noise and distortion performance than you can achieve. I (cynically) that when a spec like that is left off the datasheet it's because it wouldn't look so hot.
In sum, I think they will work but if you have a choice, 2sa1302/2sc3281 or 2sa1943/2sc5200 will work better. In any case the difference may well be inaudible.
The ability to dissapate heat is not quite as good as the 2sa1302/2sc3281 plus the package design is not the best for mounting to a heatsink. I would suggest you use a clip or a bar across the encapsulated part of the package to hold it to the heatsink rather than just a bolt through the hole on the upper part of the tab.
Finally, I wish the datasheet showed fT since this bears some relationship to the noise and distortion performance than you can achieve. I (cynically) that when a spec like that is left off the datasheet it's because it wouldn't look so hot.
In sum, I think they will work but if you have a choice, 2sa1302/2sc3281 or 2sa1943/2sc5200 will work better. In any case the difference may well be inaudible.
Mik
Apparently the latest combination is MJL4281A / MJL4202A. The P3A is at its best with this combination according to Rod Elliott. For more details
http://sound.westhost.com/project3a.htm
I hope this is useful.
Cheers.
Brownlow
Apparently the latest combination is MJL4281A / MJL4202A. The P3A is at its best with this combination according to Rod Elliott. For more details
http://sound.westhost.com/project3a.htm
I hope this is useful.
Cheers.
Brownlow
I use those transistors on my power amps, its an excellent choice... believe me that distortion isn’t a problem, my power amp has much lower distortion than an OPA267 with a loudspeaker as load(something like less 20dB at 20khz)...and they have a benefit, they are easier to get stable!
very nice choice!
regards
very nice choice!
regards
bd249 / 250
I used the c-types in various applications: power supplies , switching and amps.
They turned out to be extremly rigid and reliable.
I used the c-types in various applications: power supplies , switching and amps.
They turned out to be extremly rigid and reliable.
bd249 / 250
I used the c-types in various applications: power supplies , switching and amps.
They turned out to be extremly rigid and reliable.
I used the c-types in various applications: power supplies , switching and amps.
They turned out to be extremly rigid and reliable.
Re: bd249 / 250
the interesting question would be "what does NOT sound good in a P3A?"
I assume more transistors will do good there. No?
the interesting question would be "what does NOT sound good in a P3A?"
I assume more transistors will do good there. No?
Hi!
In asking Rod himself he said that all bipolar transistors are suitable, if they at least match the rating of the lowest ones he recommends (voltage ratings, and all other params).
If you can't reach the voltage rating required, you could always lower the rails and therefore the voltage swing, at the cost of reducing output power of your amp.
So far I always use MJ15003 / MJ15004 for all ESP projects, since nowadays they aren't as expensive as they were some years ago, and offer excellent performance. Sadly those new ON-Semi transistors Rod frecommends aren't easily available for private uses in Germany.
As for sound, try it out and judge yourself.
I did not hear any differences at all between my MJ15003 / MJ15004 setup (with BD139 / 140 as drivers), and a test setup using Sanken 2SA216 / 2SC2922 (some say the best audio bipolars out there) together with 2SB1188 / 2SD1763 as drivers (the same setup as LCAudio End Millenium).
Bye,
Arndt
In asking Rod himself he said that all bipolar transistors are suitable, if they at least match the rating of the lowest ones he recommends (voltage ratings, and all other params).
If you can't reach the voltage rating required, you could always lower the rails and therefore the voltage swing, at the cost of reducing output power of your amp.
So far I always use MJ15003 / MJ15004 for all ESP projects, since nowadays they aren't as expensive as they were some years ago, and offer excellent performance. Sadly those new ON-Semi transistors Rod frecommends aren't easily available for private uses in Germany.
As for sound, try it out and judge yourself.
I did not hear any differences at all between my MJ15003 / MJ15004 setup (with BD139 / 140 as drivers), and a test setup using Sanken 2SA216 / 2SC2922 (some say the best audio bipolars out there) together with 2SB1188 / 2SD1763 as drivers (the same setup as LCAudio End Millenium).
Bye,
Arndt
are u telling me that u've tryed 2sa1516/2sc2922 and worked corectly?
How many watt did u get? And did u used the oreginal schematic?
How many watt did u get? And did u used the oreginal schematic?
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