Hello, good day everyone!
I am a student here in Philippines, im currently doing my project. But since my country lacks of electrical parts, I cant find these parts here. And I needed to replace this.
Is there something that is similar to these that I can use?
BDX67B or BDX67C
BDX66B or BDX66C
maximum collector-emitter voltage = 100 V
maximum collector current = 16 A
maximum thermal loss = 150 W
My teacher wont give me some advice, so I just have no one else to come to so Im hoping this forum can help.
This is my project, maybe it can help: 100W Audio Amplifier
Sorry for my very bad English. If you have any other questions, please do not hesitate to ask me.
Thanks advance
and
God bless!
I am a student here in Philippines, im currently doing my project. But since my country lacks of electrical parts, I cant find these parts here. And I needed to replace this.
Is there something that is similar to these that I can use?
BDX67B or BDX67C
BDX66B or BDX66C
maximum collector-emitter voltage = 100 V
maximum collector current = 16 A
maximum thermal loss = 150 W
My teacher wont give me some advice, so I just have no one else to come to so Im hoping this forum can help.
This is my project, maybe it can help: 100W Audio Amplifier
Sorry for my very bad English. If you have any other questions, please do not hesitate to ask me.
Thanks advance
and
God bless!
That project is fine but **OLD**, and probably pulled from some Elektor Magazine from the 80's .
Metalliic TO3 case power Datlingtons went out of fashion LONG ago and if you find them today, seller may ask $15 to $25 each ... simply not needed and not worth it.
Replace them by very popular and available TIP142/TIP147 which will work fine in that amplifier and cost less than $2 each, and be available anywhere.
Mounting changes a little, you will get them in rectangular TO247 case, use rectangular matching mica of course, use single screw mounting and after mounting each on its heat sink, cut legs about 8 or 10 mm long and bend them upwards in the middle, then you can solder wires coming from the PCB to these leg stubs.
You must also attach the bias transistor (T3) to one heat sink: you may Epoxy it in place or drill a 6mm hole in one of them and put bias transistor inside it, with a little thermal grease (or Epoxy).
EDIT:yes, I know TIPs are 10A and 125W each, yet they are perfectly fine in this amplifier.
Metalliic TO3 case power Datlingtons went out of fashion LONG ago and if you find them today, seller may ask $15 to $25 each ... simply not needed and not worth it.
Replace them by very popular and available TIP142/TIP147 which will work fine in that amplifier and cost less than $2 each, and be available anywhere.
Mounting changes a little, you will get them in rectangular TO247 case, use rectangular matching mica of course, use single screw mounting and after mounting each on its heat sink, cut legs about 8 or 10 mm long and bend them upwards in the middle, then you can solder wires coming from the PCB to these leg stubs.
You must also attach the bias transistor (T3) to one heat sink: you may Epoxy it in place or drill a 6mm hole in one of them and put bias transistor inside it, with a little thermal grease (or Epoxy).
EDIT:yes, I know TIPs are 10A and 125W each, yet they are perfectly fine in this amplifier.
I agree with most written by JMFahey
The only point I don't completely agree is that TIP142/TIP147 are a little bit optimistic for a 100 W amplifier especially on SOA (Safe Operating Area)
I suggest to read 60-100W Hi-Fi Power Amplifier by Rod Elliott
60-80W Power Amplifier
It is a very good project and as well as well documented with current and readily available semiconductors.
BDX6XX transistors are now obsolete
The only point I don't completely agree is that TIP142/TIP147 are a little bit optimistic for a 100 W amplifier especially on SOA (Safe Operating Area)
I suggest to read 60-100W Hi-Fi Power Amplifier by Rod Elliott
60-80W Power Amplifier
It is a very good project and as well as well documented with current and readily available semiconductors.
BDX6XX transistors are now obsolete
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Hi Simplestudent,
The BDX66C and BDX67C both produced by Inchange are sold by Reichelt (Elektronik und Technik bei reichelt elektronik günstig bestellen) in Germany, and are not so pricey.
I hope that this can help you.
Best regards
rephil
I did find 2N6052 and 2N6059 on Amazon, but you can go to Digikey and do a parameter search that covers several brands. Transistors - Bipolar (BJT) - Single | Discrete Semiconductor Products | DigiKey
Products from Digikey are from more reliable sources than Amazon.
As others have noted, this is an OLD design that has issues. You can expect to destroy at least one set of transistors so if you go ahead with this amp, you should have spares.
Until you can design the whole circuit yourself, I would recommend building a modest ~20W amp that uses cheap $1 parts. Or, it would be no less diy to just buy amplifier modules from Amazon/China.
Products from Digikey are from more reliable sources than Amazon.
As others have noted, this is an OLD design that has issues. You can expect to destroy at least one set of transistors so if you go ahead with this amp, you should have spares.
Until you can design the whole circuit yourself, I would recommend building a modest ~20W amp that uses cheap $1 parts. Or, it would be no less diy to just buy amplifier modules from Amazon/China.
Hello, good day!
Thank you for your reply, but what do you mean he is being optimistic about it? Im sorry, because for now, I cant see the datasheet of the TIP142/147 due to slow internet here in my country and thats why im asking.
I would love to use the 60-100W Hi-Fi Power Amplifier by Rod Elliott, but It is already taken by one of my classmates. We cant have the same project. Thats why im stucked on this project since all the good 100+ Power amplifier are already taken.
Sorry for my Bad English, if you dont understand something, please do not hesitate to ask me.
Thanks again
and
God bless!
Thanks for your reply!
Yes it is not pricey but the shipment cost to my country is not
Hi, good day! Thanks for your reply!
Yes, but sadly Im stucked to this project. Since our project requires 100w+ and all the other good 100w+ power amp in the internet are already taken by our classmates.
I will look the 2N6052 and 2N6059 datasheet soon after our internet service comes to normal.
Thank you very much and God bless!
Hello, good day!
Thank you very much for your reply JMFahey, but what do you mean by "Replace them by TIP142/TIP147"? Do you mean I will replace both BDX66B/C and BDX67B/C to either of these two? (TIP142 or TIP147)?
Im sorry, because now I cant see the datasheet of TIP142 and 147 for now since our interner service here in my country sucks thats why im asking.
And lastly what is a "rectangular matching mica"?
Im sorry for asking, I just want to be sure since Im not good at understanding English.
Thanks again
and
God Bless!
Optimistic is referred to two main points - amplifier load and transistor SOA.
When you design an audio amplifier you have to design for a complex (capacitive / inductive) load - not a resistive one. I.E. you have an elliptic load line *not* a linear load line.
This means that the output transistors have to bear much more current at "high" voltage with a complex load than with a resistive load
For a good explanation about complex load and SOA (Safe Operation Area) read:
https://www.apexanalog.com/resources/appnotes/an22u.pdf
http://sound.whsites.net/patd.htm point 1.0 The Loudspeaker Load and point 1.1 Phase angle Vs. Tranistor Dissipation
Returnig at our transistors:
**** TIP142
- Power Dissipation 125 W
- 4.17 A @ 30 V -> 125 W
- 1.3 A @ 50 V -> 65 W
**** MJL21194
- Power Dissipation 200 W
- 6,67 A @ 30 V -> 200 W W
- 4 A @ 50 V -> 200 W
At "high" Vce voltage (50 V) the MJL21194 bears 3 times the power of TIP42. That means that is more suitable to drive reactive loads.
If you put 2 TIP142 in parallel you get 65 * 2 = 130 W @ 50 V
Draw your elliptic load line and choose the required transistor.
On diyaudio.com there are many interesting threads about complex load, elliptic load line and SOA
One good starting point is designing for a load 6 ohm and 45 degree phase angle
Rod Elliot writes:
"or a budget system, you can use TIP35C (NPN) and TIP36C (PNP) [cut] they can still drive a 4 ohm load from ±35V supplies. [cut]
the maximum unloaded supply voltage is ±35V!"
TIP35C/36C have a power dissipation similar to TIP142/147 so if you use TIP 142/147 you are restricted to +/- 35 V powewr supply and you will not be able to use the original power supply of your amplifier (+/- 40V - 44 V)
**** Note
Pay attention that MJL21194 and TIP35C are single transistors while TIP142 is a darlington transistor so you have to use a driver transistor to form a "discrete darlington".
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A 100W amplifier into 8 ohms is a challenge for a beginner. You need 40V peak into 8 ohms so the PSU will be needed to be +/-45 on load and probably +/-50V with light loading. That needs substantial transistors. As a "rule of thumb" the transistors need to be able to handle full power at 50V, which would would mean you could not rely on a single pair of TIP142/147 even though they are rated at 100V. The datasheet I have seen from ST says the second breakdown rating is even worse than diy_audio_fo says: only 0.9A at 50V=45w. A loudspeaker is reactive, and reactive loads means that the current needed is out of phase (to some extent, depending on the overall impedances of the system) to the voltage. Darlington transistors are useful for low voltage applications but are not widely used for high power systems because of this second breakdown problem.
I would urge you to consider whether you could use 100W with a 4 ohm load. The supply voltages are safer but you trade off against needing higher currents, which still needs thought in regards of power supply wiring.
If 8 ohm is your target I suggest using metal can MJ21193 (PNP) /MJ21194 (NPN).At 250W they are a little better than the plastic versions, but can be expensive now, though a single pair will drive your 100W.
The MJL21193/MJL21194 might just work as a single pair but I'd personally use a parallel pair for ruggedness of the system.
You will need to add driver transistors as these are not Darlingtons as pointed out in the previous post. MJE15034 (NPN) and MJE15035 (PNP) would be my recommendation. Other transistors in your amplifier will need to be rated at 120V for safety in the pre-driver stages, although the input pair could be 60V.
I would urge you to consider whether you could use 100W with a 4 ohm load. The supply voltages are safer but you trade off against needing higher currents, which still needs thought in regards of power supply wiring.
If 8 ohm is your target I suggest using metal can MJ21193 (PNP) /MJ21194 (NPN).At 250W they are a little better than the plastic versions, but can be expensive now, though a single pair will drive your 100W.
The MJL21193/MJL21194 might just work as a single pair but I'd personally use a parallel pair for ruggedness of the system.
You will need to add driver transistors as these are not Darlingtons as pointed out in the previous post. MJE15034 (NPN) and MJE15035 (PNP) would be my recommendation. Other transistors in your amplifier will need to be rated at 120V for safety in the pre-driver stages, although the input pair could be 60V.
No, BDX66 and BDX 67 are a complementary Darlington pair, one is NPN =BDX67 and can be replaced by TIP142 , the other is PNP=BDX66 and can be replaced by TIP147 .
I see Forum Members are suggesting the "safest" replacement routine, meaning "replace only by same or improved specs parts" .
Fine with me, it´s a prudent path, specially if reference is only datasheets or somebody else´s Internet pages, but rest assured that in that amplifier, with that load (4 or 8 ohm) and that supply (+/-40Volts), TIP142 - TIP 147 pairs (one of each as needed) will work properly .
Not "datasheet only" or "reading it somewhere" but solid experience: I make Guitar amplifiers, about 14000 delivered by now, since 1969, and since 2004/2006 I have delivered some 4000 100W Guitar/Bass/Keyboard/PA amplifiers each powered by a single TIP142/147 pair.
Although Live Sound/Musical Instrument service is grueling, because Musicians *routinely* play amplifiers full tilt, saturating/clipping them all the time, transport them all over the place, often use bad speaker cables, standard connector is horrible 6.35mm plug and jack, sometimes plug extra speakers "because they have them" or miswire cabinets or use shielded guitar cords instead of proper thickish parallel speaker wire ... yet these amplifiers perform faithfully for many years, with a very very low failure rate.
That´s why I can recommend them in confidence.
You might call them "tested in combat" ... and you wouldn´t be too far from the truth.
Shouldn´t be needed, but as an extra reassurance, huge Marshall amplification, "the" most recognized name and image in MI amplification, made and sold tens of thousands of Valvestate 80 and Valvestate 100 amplifiers sinceb the early 90's , powered originally by a single pair of BDV64/BDV65 transistors, and after the first couple years replaced them with a single pair of easier to source TIP142/147.
Specs?:
BDV64/65: 10 AMPERE DARLINGTON
COMPLEMENTARY SILICON
POWER TRANSISTORS
60−80−100−120 VOLTS,
125 WATTS
TIP142/147: 10 AMPERE
DARLINGTON
COMPLEMENTARY SILICON
POWER TRANSISTORS
60−100 VOLTS, 125 WATTS
As you see, they were definitely in the same league, if one was found suitable for a 100W amplifier, the other is also suitable.
So they switched to TIP142/147 .
The datasheet was kindly posted above but if you have any problem opening it, I can repost another copy.
Original suggested BDX transistors have the familiar "fried egg" TO3 metallic case, excellent but now replaced in many uses by a rectangular plastic case.
Obviously the insulating mica needed by each case type is different, and the modern plastic one uses a rectangular mica (and thermal grease).
Your Teacher should not have ordered all of you to *start* building a powerful complex amplifier, simply because required skills are not acquired all at once in a single build, the ladder has many steps which must be climbed one by one.
A more logical sequence would have been to start with a simple one transistor preamp > simple 1W amp ((LM380) > simple 5W to 15W chipamp (from TDA2003 to TDA2030) > mid complexity chipamp (LM3886) > 100W discrete amp.
Almost forgot: power your amplifier with a 30+30V 2,5A (or 3A) transformer, maybe classic EI type or toroidal, whatever you get locally.
Don´t worry about that
Just curious, what other Language(s) do you speak?
You´re welcome.
The key to making an amplifier with 40 volt rails using TIP142/7 outputs safe is all in the application. They have enough safe area for an instrument amp but not really enough for hi fi. It will produce 100 watts at 4 ohms, with the supply dropping to about +/- 34 volts when putting out the 100 watt sine wave. In the MI application you would set the current limit circuit to aggressively limit, within 5 milliseconds, to 10 amps at clipping and 3 into a zero crossing. This will allow just enough current to drive two 8 ohm single driver MI speakers to full output - but absolutely no more. It will stay within the transistors ratings and therefore be safe - no matter what the user does to it. If he hooks up more speakers it limits. If he shorts the speaker wires out it limits. When running full output at the speakers minimum impedance it will just start to limit - but with a single tone excitation any distortion caused by the limiting will be tolerable.
The same protection scheme used in a hi fi music amp will NOT be inaudible with a typical 4 ohm load. It will with 8ohms, and the amp will run fine - as a 50watt amplifier. But we want 100 watts and run 4 ohm speakers. So the obvious solution is to relax the SOA protection until it is inaudible. Then someone hooks up their WWMTMs that dip down to two and a half ohms at 200 Hz, cranks up compressed rock music, and an hour later the amp dies. Or the first time he shorts the speaker out the amp dies. Unless higher capability transistors are used.
The OP’s original circuit doesn’t have very aggressive current limiting. It would be ok for very short durations, but I wouldn’t count on it. If he just runs a 8 ohm speaker, perhaps 6 ohm, and is careful not to short it out it would be fine. But not fail safe. Good enough for demonstration for his class? Probably.
The same protection scheme used in a hi fi music amp will NOT be inaudible with a typical 4 ohm load. It will with 8ohms, and the amp will run fine - as a 50watt amplifier. But we want 100 watts and run 4 ohm speakers. So the obvious solution is to relax the SOA protection until it is inaudible. Then someone hooks up their WWMTMs that dip down to two and a half ohms at 200 Hz, cranks up compressed rock music, and an hour later the amp dies. Or the first time he shorts the speaker out the amp dies. Unless higher capability transistors are used.
The OP’s original circuit doesn’t have very aggressive current limiting. It would be ok for very short durations, but I wouldn’t count on it. If he just runs a 8 ohm speaker, perhaps 6 ohm, and is careful not to short it out it would be fine. But not fail safe. Good enough for demonstration for his class? Probably.
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