Can I build up these Darlington transistor if I use two BJT transistor ?

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Hello

It is possible to build up successful (to get the same quality sound) the BDX53C /BDX54C medium power darlington transistors .
Data sheet with the internal circuit available here !
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/4103.pdf
The reason I want to build up these darlington I want to get high power darlington close to the BDX type
For example
I chose for driver MJE15030 /15031 Minimum hFE=40
For power transistor MJW21195 /21196 Minimum hFE=20
The BDX53C/54C min hFE=750
If I do these calculation I get close hFE 40x20=800
I also have at hand MJL21193/94 similar like another power transistors but with more power .
Of course I ad the 10K & 150R resistors and also a diode .
Any comment , help , advise please :confused:
Thank you very much
Cheers
 
Thanks for the advise
The Tip has different internal circuit .
It uses 5K resistor instead 10K , but I tested and is not the best replacement !
TIP142 pdf, TIP142 description, TIP142 datasheets, TIP142 view ::: ALLDATASHEET :::
I want to get some darlington for these amplifier (picture attached)
BDW83C /84C would be the best choice but no longer available BDW84C at least not in good quality . Like ST , Texas I. or Philips only some Chinese cheap bad quality. Or some fake ST.
Now I have these amplifier , I like it a lot . I use BDW93C / 94C a bit powerless since those are medium (small) power darlingtons . Also I want to crank up the bias min 400mA. Of course with lower PS .
I tried to parallel them but impossible to match (at home) the darlingtons and sound bad with the unmatched power transistors !
If you look at the BDX53C/54C data you can see that darlington was design for audio to.
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/4103.pdf
There are some high power darlintons like MJ11015 /16 but the same problem .
The internal resistor value are different and it sound awful .
I tested , the best it would be to use two BJT and build the darlington .
Thanks for the advise one more time:)

Greetings
 

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Hello
Yes you right , but in the bass region became very light .
Otherwise these amplifier sound incredible with the BDW93C/94C now .
I'm just listening , huge bass nice mids tube like sound . But only with 100mA bias .
I still worried these small transistor will blew up .
I can use 18V power supply but I will end up with a 5W amplifier .
If I replace the power transistor different type what is on the schematic the sound become total different .
Thin , no longer soft tube like . I have a lot of great ON semi high power and driver transistors at home . I do not believe is impossible to build up these darlington with the same resistors etc .
I just need some advise because I never did it before .
Greetings
 
Thank you
I know but those are low power darlingtons unfortunately .
To use them in parallel I supposed to match them which is not so simple .
For me BDW83C /84C would be great . But 84C no longer available , just some fake ST or cheap useless Chinese parts ..
I ordered from Germany Reichelt BDW83C/84C but cheap garbage .
From ST company the smaller BDW93C/94C works great but low power ..
I would like to rase the bias up to 400mA.
That is the reason I need high power darlington

Cheers
 
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Hello
Yes you right , but in the bass region became very light .
Otherwise these amplifier sound incredible with the BDW93C/94C now .
I'm just listening , huge bass nice mids tube like sound . But only with 100mA bias .
I still worried these small transistor will blew up .
I can use 18V power supply but I will end up with a 5W amplifier .
If I replace the power transistor different type what is on the schematic the sound become total different .
Thin , no longer soft tube like . I have a lot of great ON semi high power and driver transistors at home . I do not believe is impossible to build up these darlington with the same resistors etc .
I just need some advise because I never did it before .
Greetings

Well one thing is that with different devices you probably need to figure out the best bias setting and adjust it to that. Did you do that already?
Different speed devices may also lead to instability or oscilatory behaviour which can alter the sound strongly. You would need to check that.

jd
 
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Hi ! sorry if i jump in with a very basic question about darlingtons.
I do not understand if there are any benefits in using a couple of bjts (a driver + power transistor) instead of just a single darlington.
And another question .. why such convenient devices are not more popular ?
I was looking for very simple amp designs using darlingtons and i ended up just with one from a Vellemann kit :confused:
The parts count is very low indeed
 

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I think your 1st question has yet been answered in the former postings.
To question #2: Darlingtons of that age are rather slowish devices. Nowadays we know that a discrete Darlington configuration (= 2EF) can be sped up significantly with a common resistor between both drivers' emitters that even can be paralleled with a capacitor of several 100 nF's. This is impossible with monolithic Darlingtons.
Best regards!
 
I think your 1st question has yet been answered in the former postings.
To question #2: Darlingtons of that age are rather slowish devices. Nowadays we know that a discrete Darlington configuration (= 2EF) can be sped up significantly with a common resistor between both drivers' emitters that even can be paralleled with a capacitor of several 100 nF's. This is impossible with monolithic Darlingtons.
Best regards!

Hi thank you very much indeed. The "discrete darlington" allows for much better performance and different circuit solutions. I guess this applies expecially to audio amps design ?
In a capacitance multiplier circuit instead speed should not be an issue.
I would like to try darlingtons there for taking profit of their high hfe :rolleyes:
 
For sure in a capacitance multiplier. But you've been showing to us an amplifier schematics?!? Best regards!
:up: perfectly right ! i was talking about amps with power supplies in mind
anyway i understand why they are not that common in amps in general.
Not always the simplest solution is the best. :eek:
actually i see them also very rarely in power supplies
Is there anyone around who still use these things ? :D
 
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Have you looked into any of the modern Sanken darlingtons? Some of them are specific for audio and don’t have the base-emitter resistors on the driver (but have it on the output) - D2390 for instance. The STDs even have a diode that one leg is brought out separately. You may end up with better results with these than with old-school BDX/BDW/TIP in EF2 applications.
 
Have you looked into any of the modern Sanken darlingtons? Some of them are specific for audio and don’t have the base-emitter resistors on the driver (but have it on the output) - D2390 for instance. The STDs even have a diode that one leg is brought out separately.
You may end up with better results with these than with old-school BDX/BDW/TIP in EF2 applications

Thanks a lot for the very valuable information. They could avoid any "embedded" resistor. Just tr1 and tr2 on the same chip ? I remember for instance the SAP 16 which have even the emitter power resistor inside the chip. Not the best design solution.
I see an hfe= 5000 min for the 2sd2390 ... the king of the cap multiplier transistor ? 5000 is a lot indeed ... if i understand well it multiplies for 5000 the uF value of a base capacitor ? :eek:
I will try one for sure. Maybe they could be a great upgrade for existing designs
 
The ones with the built in emitter resistors are bad news. The resistor makes a really nice fuse. Prevents collateral damage to a board for sure, it blows as easily as a 10 amp quick blow 3AG. Use with caution or be prepared to change them any time the speaker wires get shorted.
 
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