Thanks for the hint...coupling is a good idea.....but is it really necessary?
Mike does not couple his input transistors isn't he?
This should be really good trannys, only a bit expensive.
Greetings
Black
Mike does not couple his input transistors isn't he?
This should be really good trannys, only a bit expensive.
Greetings
Black
BlacK_Chicken said:
I don't know enough to say whether it's necessary. But if you can bend transistor leads around to fit a different pin layout, you can couple them just as easy.
Sheldon
Hi Black,
Coupling and matching are important. That's why they are laid out close together on the board. That is also why prepackaged matched pairs were available and expensive.
Somewhere "back there" you can find a post of mine with pictures. I nrmally match, grease and enclose pairs in heatshrink tubing. Marantz had some great spring clamps that held the transistors together and was also grounded.
-Chris
Coupling and matching are important. That's why they are laid out close together on the board. That is also why prepackaged matched pairs were available and expensive.
Somewhere "back there" you can find a post of mine with pictures. I nrmally match, grease and enclose pairs in heatshrink tubing. Marantz had some great spring clamps that held the transistors together and was also grounded.
-Chris
Sure mmatching should definately be done. I will couple the also with hiet shrinking tube.
It was just a thought of mine, if it is really necessary.
Thanks a lot for your help.
bye
Black
It was just a thought of mine, if it is really necessary.
Thanks a lot for your help.
bye
Black
Hi
I’m currently reading this thread and the design seems interesting and I think I will built it.
I am at page 25 of the thread and I don’t know is someone asked the same question at the following pages.
I would like to ask about the driver transistors which can be found but are a bit expensive, can they be changed with D44H11 & D45H11 (same pins 80v 10A 70W 50MHZ hfe=60) which is cheaper and is designed for driver applications, I don’t know if the bandwidth of 50Mhz will cause problems.
The second question is about the output transistors MJL3281A/MJL1302A which I can’t find anywhere, can I use another transistor, can i find them in a eshop?
I found the following replacements in datasheets 2SC3281/2SA1302, are these ok to use, any other recommendation?
Thank you
Alex
I’m currently reading this thread and the design seems interesting and I think I will built it.
I am at page 25 of the thread and I don’t know is someone asked the same question at the following pages.
I would like to ask about the driver transistors which can be found but are a bit expensive, can they be changed with D44H11 & D45H11 (same pins 80v 10A 70W 50MHZ hfe=60) which is cheaper and is designed for driver applications, I don’t know if the bandwidth of 50Mhz will cause problems.
The second question is about the output transistors MJL3281A/MJL1302A which I can’t find anywhere, can I use another transistor, can i find them in a eshop?
I found the following replacements in datasheets 2SC3281/2SA1302, are these ok to use, any other recommendation?
Thank you
Alex
Hi Alex,
Any 2SC3281 / 2SA1302's you find are probably fakes. The MJL3281A / MJL1302A pair ought to be easy to get from any stocking On Semi distributor. You can get the original drivers at the same time.
-Chris
Any 2SC3281 / 2SA1302's you find are probably fakes. The MJL3281A / MJL1302A pair ought to be easy to get from any stocking On Semi distributor. You can get the original drivers at the same time.
-Chris
Alex, the 2SC3281/2SA1302 can't be recommended (As Chris already said) unless they were pulled out of an old amp.
You could use 2SC5200/2SA1943, but only buy from reliable source !
About your suggested drivers, i don't know them, but 80v seems a bit low. (also hfe = 60)
If you find a good source for 2SC5200/2SA1943 (Toshiba), look for some nice toshiba or sanyo drivers. The drivers need hfe of min 100.
Maybe:
2sa1930/2sc5171 Toshiba
2sc2344/2sa1011 Sanyo
2sc3298/2sa1306 Toshiba
Mike
You could use 2SC5200/2SA1943, but only buy from reliable source !
About your suggested drivers, i don't know them, but 80v seems a bit low. (also hfe = 60)
If you find a good source for 2SC5200/2SA1943 (Toshiba), look for some nice toshiba or sanyo drivers. The drivers need hfe of min 100.
Maybe:
2sa1930/2sc5171 Toshiba
2sc2344/2sa1011 Sanyo
2sc3298/2sa1306 Toshiba
Mike
Thank you both for your replies and recommendations.
I read about fake transistors here
http://sound.westhost.com/counterfeit.htm
but i didn't think that almost all the suppliers sell fakes.
I know about D44H11/D45H11 because they were used in the Walt Jung super regulator (because they were very fast), you probably know about it
Jung Regulator articles
I have build a modified version which can be found here in pdf manual
http://www.alw.audio.dsl.pipex.com/products.htm
Alex
I read about fake transistors here
http://sound.westhost.com/counterfeit.htm
but i didn't think that almost all the suppliers sell fakes.
I know about D44H11/D45H11 because they were used in the Walt Jung super regulator (because they were very fast), you probably know about it
Jung Regulator articles
I have build a modified version which can be found here in pdf manual
http://www.alw.audio.dsl.pipex.com/products.htm
Alex
Hi Alex,
Mike has an excellent list of driver pairs there. I like the Toshiba products better.
-Chris
They have been out of production a long time now. They were very popular and may have been the first really good fakes. Forget them, the odds are against you finding some real ones unless you pull them from a piece of old equipment yourself.
Mike has an excellent list of driver pairs there. I like the Toshiba products better.
-Chris
Hi Alex,
You can also use Toshiba's 2SA1837/2SC4793 for drivers. Hfe of 100 to 320. I've used them with Symasym and work great.
Al
You can also use Toshiba's 2SA1837/2SC4793 for drivers. Hfe of 100 to 320. I've used them with Symasym and work great.
Al
Those ones are the drivers i use AAK
Well...they are my standard drivers to all amplifiers i use to make within this power and voltage range.
They sound very good...simple and reliable...cheap plastic ones....no need to insulate nothing.
I love to compare amplifiers...this way, i use the same transistors...so.... if the sound is different, beeing the same transistors, they will be out of suspections.
regards,
Carlos
Well...they are my standard drivers to all amplifiers i use to make within this power and voltage range.
They sound very good...simple and reliable...cheap plastic ones....no need to insulate nothing.
I love to compare amplifiers...this way, i use the same transistors...so.... if the sound is different, beeing the same transistors, they will be out of suspections.
regards,
Carlos
I also found the 2SA1837/2SC4793 drivers, great.
As for the output transistors I think i'll wait and try to find the MJL3281A/MJL1302A bacause they seem to have better gain linearity compared to MJL4281A/MJL4302A accordind to the onsemi datasheets.
Alex
As for the output transistors I think i'll wait and try to find the MJL3281A/MJL1302A bacause they seem to have better gain linearity compared to MJL4281A/MJL4302A accordind to the onsemi datasheets.
Alex
Hi alexan, I will recommend mjw0302 and mjw0281, from ONsemi sample program (see link below)
They are the best finals in therms of liniarity, matched from factory in less than 10%.
http://www.onsemi.com/PowerSolutions/sampleKit.do?rpn=MJW0281A
They are the best finals in therms of liniarity, matched from factory in less than 10%.
http://www.onsemi.com/PowerSolutions/sampleKit.do?rpn=MJW0281A
roender said:
Thank you, i'll check it
-_nando-_ said:
The shipping cost is too high and i think there is also a minimum order.
Alex
Man, what a horrible mistake in my english, give me a discount, I was tired 
Farnell is my master distribuitor, because it is in Brazil, so there's no shipping costs, I drive my car and I get the components by myself 😎
Dec. 12 all the components will arrive, and as soon as possible I'll give a feedback of this great amplifier.
Best Regards
Farnell is my master distribuitor, because it is in Brazil, so there's no shipping costs, I drive my car and I get the components by myself 😎
Dec. 12 all the components will arrive, and as soon as possible I'll give a feedback of this great amplifier.
Best Regards