Don't like to be a kill joy but common guys this geriatric semis ....I refuse to work on something like Tip 142-147 which is actually a transistor to drive solenoids and you may check on any data sheet there is no audio specifications ....
my position about darlingtons is stated here many times before don't have to repeat it once more .
I simply challenge you to place the datasheet of various Tip 142 from trusted manufacturer up in the air so everybody can see and you will understand that each and every one of them has a different configuration between the driver and the output transistor ....
That exists in the datasheet in real life will be also batch and order depending ....
You cant guarantee specs like that .....
kind regards
sakis
my position about darlingtons is stated here many times before don't have to repeat it once more .
I simply challenge you to place the datasheet of various Tip 142 from trusted manufacturer up in the air so everybody can see and you will understand that each and every one of them has a different configuration between the driver and the output transistor ....
That exists in the datasheet in real life will be also batch and order depending ....
You cant guarantee specs like that .....
kind regards
sakis
Hello
Yes the the high bias was intentional. Sound a bit better. With lower bias the amp stable and sound great to, probably with higher bias if get the right size heat sink stable to.
Please use on the input BC550C/ 560C or 2SK170BL 2SJ74BL. The J Fet has to be rotated 180 degree.
I advise use the MJE 243/353 for VAS and TIP will do the power section.
To get read of the offset you can play with the input transistors or better to replace one of the 68K with a 100K (set up around 68K) multi turn trimmer and adjust it until the bias 0V.
I warn you when you do any adjustment please do not use your speakers under any circumstances!
The transistor blow up that $2 or so but a speaker can be $$$...
The amplifier is very sensitive even to the last piece of wire.. The input capacitor 4.7uF , I use BG non-polar. That is the best to me. If you build one PS for the two channel please use at least 4X10 000uF caps like CRC set up.
Once you hear the amp after you can't give it up!
You can use the layout I uploaded earlier, I will help with the stuffing.
Greetings Gabor
Yes the the high bias was intentional. Sound a bit better. With lower bias the amp stable and sound great to, probably with higher bias if get the right size heat sink stable to.
Please use on the input BC550C/ 560C or 2SK170BL 2SJ74BL. The J Fet has to be rotated 180 degree.
I advise use the MJE 243/353 for VAS and TIP will do the power section.
To get read of the offset you can play with the input transistors or better to replace one of the 68K with a 100K (set up around 68K) multi turn trimmer and adjust it until the bias 0V.
I warn you when you do any adjustment please do not use your speakers under any circumstances!
The transistor blow up that $2 or so but a speaker can be $$$...
The amplifier is very sensitive even to the last piece of wire.. The input capacitor 4.7uF , I use BG non-polar. That is the best to me. If you build one PS for the two channel please use at least 4X10 000uF caps like CRC set up.
Once you hear the amp after you can't give it up!
You can use the layout I uploaded earlier, I will help with the stuffing.
Greetings Gabor
Hello Sakis
Would you please!!!!!! you already posted here these message a couple times.
If the TIP 142/147 or MJ11015/16 transistor works (and good as a replacement) to Nelson Pass A40 Class A amplifier why not good here???
Did you tested the amp?
If yes please post your opinion otherwise let those people who want test it and post their opinion.
Nothing personal I just don't like you always come with these because you hate all Darlington devices. I read your opinion about all Darlington many times!
All my respect to you! I know you are a guy with a lot of knowledge & experience but sometimes we need to taste that food to (feel the taste) decide if is good or bad...
Again nothing personal OK, all my respect to you!
Greetings Gabor
Would you please!!!!!! you already posted here these message a couple times.
If the TIP 142/147 or MJ11015/16 transistor works (and good as a replacement) to Nelson Pass A40 Class A amplifier why not good here???
Did you tested the amp?
If yes please post your opinion otherwise let those people who want test it and post their opinion.
Nothing personal I just don't like you always come with these because you hate all Darlington devices. I read your opinion about all Darlington many times!
All my respect to you! I know you are a guy with a lot of knowledge & experience but sometimes we need to taste that food to (feel the taste) decide if is good or bad...
Again nothing personal OK, all my respect to you!
Greetings Gabor
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"if the TIP 142/147 or MJ11015/16 transistor works (and good as a replacement) to Nelson Pass A40 Class A amplifier why not good here"
The original transistors in the Pass A40 were selected for their very low value of the base-to-emitter resistor that is not seen in other parts.
Discrete connected components are to be preferred.
The original transistors in the Pass A40 were selected for their very low value of the base-to-emitter resistor that is not seen in other parts.
Discrete connected components are to be preferred.
Hello
If you have TIP just give them a try. There are many device not made for audio and many designer use those successfull.
Also many valve was not made for audio and they are great for audio project, some of them are the best.
You can find a lot of circuit where the darlington was built up from two transistor like the Hiraga Class A so on.
I did tried to build up the darlington from two audio transistor but the result was not very promissing at all. You have to calculate the speed , capacitance etc
I know Sakis hate all the darlingtons, AND I respect that.
He should respect also those who use those devices or at least give a try .
Several famous amp was built with darlington power transistors. Not very popular but still can be found or used.
Sanken produce darlingtons for audio to. There are several darlington pack (IC) for audio to.
I do respect Sakis I did learned a lot from him I hope I will do in the future to! I do not want to write about these topic any more.....
Again if N Pass can use these device at the A40 we can to. That is a great sounding amp. Many people still use the A40 even do that is a very old design.
Greetings Gabor
If you have TIP just give them a try. There are many device not made for audio and many designer use those successfull.
Also many valve was not made for audio and they are great for audio project, some of them are the best.
You can find a lot of circuit where the darlington was built up from two transistor like the Hiraga Class A so on.
I did tried to build up the darlington from two audio transistor but the result was not very promissing at all. You have to calculate the speed , capacitance etc
I know Sakis hate all the darlingtons, AND I respect that.
He should respect also those who use those devices or at least give a try .
Several famous amp was built with darlington power transistors. Not very popular but still can be found or used.
Sanken produce darlingtons for audio to. There are several darlington pack (IC) for audio to.
I do respect Sakis I did learned a lot from him I hope I will do in the future to! I do not want to write about these topic any more.....
Again if N Pass can use these device at the A40 we can to. That is a great sounding amp. Many people still use the A40 even do that is a very old design.
Greetings Gabor
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"Again if N Pass can use these device at the A40 we can to."
Q7-10 are special complementary Darlington transistors, chosen
especially for their rugged safe operating area and the 25 Ohm value of
their internal driver's emitter resistor. These cannot be adjusted by the
user and most manufacturers use about 100 Ohms in this spot, which
results in far less bias on the driver transistor.
Q7-10 are special complementary Darlington transistors, chosen
especially for their rugged safe operating area and the 25 Ohm value of
their internal driver's emitter resistor. These cannot be adjusted by the
user and most manufacturers use about 100 Ohms in this spot, which
results in far less bias on the driver transistor.
Darlingtons and CFP amps are usually precise units. The transistors are prone to instability (and consist of 2 fixed parts) so the design is rarely flexible to part change.
With BJT amps we can usually roll transistors, but usually not with darlington amps. TIP142/147 is probably one of the most problematic. I can't even find a spice model that works. MJ110xx are also very prone to instability.
If the amp was designed for BDW, then even if they are slow or not good according to Wahab, they are usually better than better transistors not suitable for the circuit.
Try 2N6284/6287 darlingtons here. They tend to be a lot more stable and have good harmonic structure. It is not difficult to work with this topology once you are familiar with it (Read SSA thread to know more).
With BJT amps we can usually roll transistors, but usually not with darlington amps. TIP142/147 is probably one of the most problematic. I can't even find a spice model that works. MJ110xx are also very prone to instability.
If the amp was designed for BDW, then even if they are slow or not good according to Wahab, they are usually better than better transistors not suitable for the circuit.
Try 2N6284/6287 darlingtons here. They tend to be a lot more stable and have good harmonic structure. It is not difficult to work with this topology once you are familiar with it (Read SSA thread to know more).
The darlington speed and inside structure resister values are very important.
These was precisely calculated by the designer into the circuit. I know him personally, he also offered the TIP darlingtons as back up when BDW from ST wasn't available at local store.
Actually he lived from my Apt. only two blocks in Budapest.
Originally (more than 20 years a go) these amp used Texas Inst darlington. No longer available..
The reason I advise ST because that work properly.
I did tested many different type BDW from other manufacturer. I ordered from Europe via my friend.
What ever he find in the store he did sent those to me.
I can tell you some of them just waste of money!
By some other company manufactured like ISC very bad device! I blew up many of them even at low bias.
Also I tried from other company but sound awful.
ST Moroco is great device. But If someone know better parts (tested or proven is good device) we can give a try.
With 3 pair BDW83D/84D at 22 rail voltage I biased the amp over 3A. I did used the amps for weeks to burn in. It was stable!
I didn't like the sound those darlington was made by other company from Philippines.
Guys the amplifier stable with the right bias and proper heatsink!!!
My friend used his amp by one pair BDW at 500mA bias over 10 years!
I advise build the amp after my experience, if you can improve the stability or the sound (nothing impossible) please let me know. One think is sure if you use the advised devises you will fall in love with these amp!
I did built up the darlington from respected Audio transistors, it was slowish, bad sounding etc.
In these circuit the BDW or TIP not slow at all.
Jay I'll take a look those darlingtons you advised, thank you. Some of the data does not share the Darlinton inside structure..
My wish someone build the amp so he can comment at least the sound!
I believe it would be the circuit more open for constructive comment, more interest for DIY.
Greetings Gabor
These was precisely calculated by the designer into the circuit. I know him personally, he also offered the TIP darlingtons as back up when BDW from ST wasn't available at local store.
Actually he lived from my Apt. only two blocks in Budapest.
Originally (more than 20 years a go) these amp used Texas Inst darlington. No longer available..
The reason I advise ST because that work properly.
I did tested many different type BDW from other manufacturer. I ordered from Europe via my friend.
What ever he find in the store he did sent those to me.
I can tell you some of them just waste of money!
By some other company manufactured like ISC very bad device! I blew up many of them even at low bias.
Also I tried from other company but sound awful.
ST Moroco is great device. But If someone know better parts (tested or proven is good device) we can give a try.
With 3 pair BDW83D/84D at 22 rail voltage I biased the amp over 3A. I did used the amps for weeks to burn in. It was stable!
I didn't like the sound those darlington was made by other company from Philippines.
Guys the amplifier stable with the right bias and proper heatsink!!!
My friend used his amp by one pair BDW at 500mA bias over 10 years!
I advise build the amp after my experience, if you can improve the stability or the sound (nothing impossible) please let me know. One think is sure if you use the advised devises you will fall in love with these amp!
I did built up the darlington from respected Audio transistors, it was slowish, bad sounding etc.
In these circuit the BDW or TIP not slow at all.
Jay I'll take a look those darlingtons you advised, thank you. Some of the data does not share the Darlinton inside structure..
My wish someone build the amp so he can comment at least the sound!
I believe it would be the circuit more open for constructive comment, more interest for DIY.
Greetings Gabor
Hello
Jay I check those darlington data, not bad at all , look better than the MJ11###. 160W & 20A....
Thank you!!
So I did ordered 2 pair from US to test them.
Let see how they will perform.
Made by ON semi but also available from ST.
It doesn't matter. The result is important to me.
The only bad think these are in TO3 pack & may PC board was designed for flat pack transistor. I have them ready...
I will use hard wire to connect them at least to test them
I need these Darlingtons because I want to test the Pass A40.
Someone who built the amp and after built the Aleph5 and Aleph4 still prefer the A40 sound.
I have the A40 stuffed boards just need the JFet and to be tested.
Greetings Gabor
Jay I check those darlington data, not bad at all , look better than the MJ11###. 160W & 20A....
Thank you!!
So I did ordered 2 pair from US to test them.
Let see how they will perform.
Made by ON semi but also available from ST.
It doesn't matter. The result is important to me.
The only bad think these are in TO3 pack & may PC board was designed for flat pack transistor. I have them ready...
I will use hard wire to connect them at least to test them
I need these Darlingtons because I want to test the Pass A40.
Someone who built the amp and after built the Aleph5 and Aleph4 still prefer the A40 sound.
I have the A40 stuffed boards just need the JFet and to be tested.
Greetings Gabor
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Even from these you can see, how important these amp to me!
Right away I got those darlingtons.
I'm a fanatic, I don't think so at least not more than other DIY-ers.
I just heard the amp in my system!
Someone came to me to purchase a par of my speakers, he didn't believed to his ear, after he follow with his hand the speaker wire from the amp to the speakers. The amp was laid out on a piece of plywood..
Right away ask me he want one! I lived at that time in Budapest.
Now I think with the reduced emitter resister from 0R47 to 0R22, the JFet input, better VAS device better caps and resisters and BG non-polar on the input took the sound of the amp much higher category.
I didn't heard better sound in my system out of a couple hundreds commercial and way over 100 DIY amp (not all built 100% many of them was just tested)..
Greetings Gabor
Right away I got those darlingtons.
I'm a fanatic, I don't think so at least not more than other DIY-ers.
I just heard the amp in my system!
Someone came to me to purchase a par of my speakers, he didn't believed to his ear, after he follow with his hand the speaker wire from the amp to the speakers. The amp was laid out on a piece of plywood..
Right away ask me he want one! I lived at that time in Budapest.
Now I think with the reduced emitter resister from 0R47 to 0R22, the JFet input, better VAS device better caps and resisters and BG non-polar on the input took the sound of the amp much higher category.
I didn't heard better sound in my system out of a couple hundreds commercial and way over 100 DIY amp (not all built 100% many of them was just tested)..
Greetings Gabor
If the Darlingtons work well for you, and sound good to you, then go with it... that is part of what DIY is about, after all
I am curious though, if you have thought to try non Darlingtons, but using a suitable output stage. For example MJE15032/3 driving MJL21193/4 for example.
I am curious though, if you have thought to try non Darlingtons, but using a suitable output stage. For example MJE15032/3 driving MJL21193/4 for example.
Hello
We did tried many different type of audio transistors several years a go.
Not even came close sound wise to the cheap BDW83C/84C
Darlington has some advantage not just bad side compare to the built up darlington circuit.
I own a half box audio transistors and mosfets.
Transistors from ON Semi, orig Toshiba, Sanken etc
Do you think I would waste my money if it would be so easy to build up the darlington to get min. the same quality sound or better but more power better linearity or performance..
To me is like to build up the power darlington pack or the LM Gain clone chip after those tests.
Why I write these because we wasted a lot of time energy with out ever come close to the cheap BDW darlinton device.
Please feel free to build the amp one side with BDW darlingtron and other side use your favorite audio device.
If you achieve the same performance please let me know. I would be the happiest person to follow you.
Someone who all his life built and fixed amplifier , speakers etc (engineer) helped me and we didn't succeed.
I do not say it is impossible but you will spend a lot of time to get good result that sure and I guarantee.
Please build and test the amp, you will realize it will be not the sound need improvement!
Greetings Gabor
I forget to ask please read at Mr. Pass advice as a transistor replacement for A40. Just to answer your previous post..
Also read He tested to and other people rebuilt (Mark Finnish also) with MJ11### darlington with out any sound degradation.
If only the low resistance would be important we could use MJ11032/33 that has only 25Ohm resistor between the driver and the power section.
http://www.onsemi.com/pub_link/Collateral/MJ11028-D.PDF
I wish it would be so simple!!!
After you test something you realize life not so easy.
Greetings Gabor
Also read He tested to and other people rebuilt (Mark Finnish also) with MJ11### darlington with out any sound degradation.
If only the low resistance would be important we could use MJ11032/33 that has only 25Ohm resistor between the driver and the power section.
http://www.onsemi.com/pub_link/Collateral/MJ11028-D.PDF
I wish it would be so simple!!!
After you test something you realize life not so easy.
Greetings Gabor
Wow! Mepco Capacitors..that was made by my wife 20years ago from Matsushita Electric Philippines.