Good Inex..some check is necessary for the amplifier.
Increase heatsinks or include a fan blower if the output is too much hot...to avoid loose your output transistors or worst, the speaker.
The amplifier was adjusted to receive only 750 milivolts of audio... this is a very low power....70 miliwatts over 8 ohms speaker.... very easy, from your car radio to overdrive your amplifier..as it can reach 3 watts easy and some of them can go to 25 watts rms.
No problems with you computer audio...but even better, despite some low frequency noise, is to use the computer speakers headphone output...those small speaker we use over the computer table.
The audio swing that may enter the amplifier is from 1 to 750 milivolts...more than 750 milivolts will saturate the output power, as it will reach the maximum possible output signal.
It is hard to adjust so small voltage into a Car radio....as every audio peak will be many times the maximum allowable to the amplifier.
To use your radio.... a 10 to 1 attenuator may be a good idea, because music is dinamic... voltage are always moving and peaks goes easily over the limits.... different than a continuous test signal, music is a little bit more complicated to adjust volume into a reasonable level....we have to pray not to increase above the limits.
Using the attenuator, your problems, related input signal, will be smaller...do not forget to use your radio into flat position...no loudness, no trebles.... the most flat possible.
Yeah..enormous impedance mismatch using a 8 ohms impedance auto radio output into an standard audio amplifier...but low impedance can drive a higher impedance without problems....the opposite is what do not works fine.
This way..watch the sketch..sorry if i am beeing too much obvious.
regards,
Carlos
Increase heatsinks or include a fan blower if the output is too much hot...to avoid loose your output transistors or worst, the speaker.
The amplifier was adjusted to receive only 750 milivolts of audio... this is a very low power....70 miliwatts over 8 ohms speaker.... very easy, from your car radio to overdrive your amplifier..as it can reach 3 watts easy and some of them can go to 25 watts rms.
No problems with you computer audio...but even better, despite some low frequency noise, is to use the computer speakers headphone output...those small speaker we use over the computer table.
The audio swing that may enter the amplifier is from 1 to 750 milivolts...more than 750 milivolts will saturate the output power, as it will reach the maximum possible output signal.
It is hard to adjust so small voltage into a Car radio....as every audio peak will be many times the maximum allowable to the amplifier.
To use your radio.... a 10 to 1 attenuator may be a good idea, because music is dinamic... voltage are always moving and peaks goes easily over the limits.... different than a continuous test signal, music is a little bit more complicated to adjust volume into a reasonable level....we have to pray not to increase above the limits.
Using the attenuator, your problems, related input signal, will be smaller...do not forget to use your radio into flat position...no loudness, no trebles.... the most flat possible.
Yeah..enormous impedance mismatch using a 8 ohms impedance auto radio output into an standard audio amplifier...but low impedance can drive a higher impedance without problems....the opposite is what do not works fine.
This way..watch the sketch..sorry if i am beeing too much obvious.
regards,
Carlos
Attachments
PCB ???
Is everybody here who build dx 100 just make it
their own PCB or some one has sell this PCB
if i look from the total page is 128, a lot of people
involve imagine if you buy good pcb and make it
profit US$ 5 wow there a big big .....
How generous destroyer x
for nordic - sorry for my bad english
...putting the fun back into dysfunctional!!!!!!!
are you dysf ?
In indonesia if people dysf* they go to doctor
not tell anyone
sorry if i was wrong
Is everybody here who build dx 100 just make it
their own PCB or some one has sell this PCB
if i look from the total page is 128, a lot of people
involve imagine if you buy good pcb and make it
profit US$ 5 wow there a big big .....
How generous destroyer x
for nordic - sorry for my bad english
...putting the fun back into dysfunctional!!!!!!!
are you dysf ?
In indonesia if people dysf* they go to doctor
not tell anyone
sorry if i was wrong
No one is selling pcboard here...no group buy or something alike.
At least, for a while, people are doing by themselves.
The one that have ordered boards, in very small quantities was Greg Erskine...but i think he has no one to sell..also i think he is not interested in this business too.
So.... put your hands on the job man!
Mine boards are travelling from Australia to Brazil...now they must be floating around Cape town in South Africa..will arrive in one week if not eated by a Southern Africa Shark, or smashed by Brasilian mail system delicated treatment (nice, kind, alike to go with a Catterpillar over them).
I had two board damaged that came from Aussie Amplifiers...Anthony Holton amplifiers...they was double faced boards, and because of bad care they had into this travel i had problems needing to bend the board with plastic things to make them work to my testing purposes..but i gave up to listen to them daily because Brazilian mailing system had destroyed them..something broken from the upper board to the lower board, as that one was double face....i did not have complained to Anthony, because i am sure he was not the guilty... the package arrived clearly smashed.
Greg is free to construct, to sell, to provide kits.... everything he want to do...but i think he will have no interest about.
Maybe a forum friend can be interested to provide boards to you... this way, beeing business...better to go directly with the guys that offer you boards....forum accept group buy or those things....profitable businesses is another story.
The guy can offer you..and them, i suggest you, and him, to jump into direct mail conversations.
regards,
Carlos
At least, for a while, people are doing by themselves.
The one that have ordered boards, in very small quantities was Greg Erskine...but i think he has no one to sell..also i think he is not interested in this business too.
So.... put your hands on the job man!
Mine boards are travelling from Australia to Brazil...now they must be floating around Cape town in South Africa..will arrive in one week if not eated by a Southern Africa Shark, or smashed by Brasilian mail system delicated treatment (nice, kind, alike to go with a Catterpillar over them).
I had two board damaged that came from Aussie Amplifiers...Anthony Holton amplifiers...they was double faced boards, and because of bad care they had into this travel i had problems needing to bend the board with plastic things to make them work to my testing purposes..but i gave up to listen to them daily because Brazilian mailing system had destroyed them..something broken from the upper board to the lower board, as that one was double face....i did not have complained to Anthony, because i am sure he was not the guilty... the package arrived clearly smashed.
Greg is free to construct, to sell, to provide kits.... everything he want to do...but i think he will have no interest about.
Maybe a forum friend can be interested to provide boards to you... this way, beeing business...better to go directly with the guys that offer you boards....forum accept group buy or those things....profitable businesses is another story.
The guy can offer you..and them, i suggest you, and him, to jump into direct mail conversations.
regards,
Carlos
Attachments
air mail service
i buy from anthony too
at the first time i want use the regular air service
but my friend say if you use fedex is US$ 120 if
use regular just +/- US$ 30 and he push me to
use fedex
I can imagine if i use the regular maybe some
component is out from PCB
all the component came with the fresh look
thanks to fedex but very expensive
Carlos please tell it your daughter im saying
that she is very pretty, wooooow
i buy from anthony too
at the first time i want use the regular air service
but my friend say if you use fedex is US$ 120 if
use regular just +/- US$ 30 and he push me to
use fedex
I can imagine if i use the regular maybe some
component is out from PCB
all the component came with the fresh look
thanks to fedex but very expensive
Carlos please tell it your daughter im saying
that she is very pretty, wooooow
I have others...more pretty than this one you could see.
I use to select my wifes to produce nice children..ahahahah.
Kidding....i just turn in passion by their beauties and i attack with all my strength..smashing them against the wall...they like agressive folks..
I am giving you enormous secret..do not forget to apologize AFTER the smashing behavior.... also never say that you are interested in sex...never...you hate sex....this is for animals...hehe
tricks..free tricks.
The problem is that you finished married ...hehe...not so clever!
ahahahaha!
regards,
Carlos
I use to select my wifes to produce nice children..ahahahah.
Kidding....i just turn in passion by their beauties and i attack with all my strength..smashing them against the wall...they like agressive folks..
I am giving you enormous secret..do not forget to apologize AFTER the smashing behavior.... also never say that you are interested in sex...never...you hate sex....this is for animals...hehe
tricks..free tricks.
The problem is that you finished married ...hehe...not so clever!
ahahahaha!
regards,
Carlos
Attachments
This one, the older one, having 25 years is a Computer Programmer.
Her husband is fine...sells cars.
And i have a son too.... Musician, plays guitar..very young and shy...very white too..her mother came from Dennmark.
Those girls have different mothers...what can i do..i love women.
regards,
Carlos
Her husband is fine...sells cars.
And i have a son too.... Musician, plays guitar..very young and shy...very white too..her mother came from Dennmark.
Those girls have different mothers...what can i do..i love women.
regards,
Carlos
Attachments
Update
Some good news the low Bias disortion is pretty much gone
I tested the amp again, using a testspeaker and the preout of a car radio(so no need for a a attenuator).
Installed some 4,7 Ohm savety resistors (didnt have 10 Ohm)
Adjusted Bias around 50-60 mA and offset to zero volts.
Conected the speaker and gues what? Disortion!
Measered the input signal, less than 100mV so thats not a problem.
Maybe the drivers have a super low gain? replaced the drivers with other mje15030/31, the result was still the same.
One driver was bended over so i tried to bend it back,then suddenly 30000µF discharged within a second(litle short in PSU)well atleast i was awake again .
Then i replaced the mje15030/31 with bd139/140, an the result was verry bad, verry much disortion, then i looked at the pcb again, damn diferent pins.
Turned the drivers around, repowered the amp and the result was a litle better than the begining(the BD got a litle higher gain i think).
nothing seems wrong with the drivers so there no problem.
then i replaced the Vas bd139 with another bd139, repowered the amp and.. the disortion is gone!
I need to do some better listning test but could not hear any anoying disortions at 60mA bias, they are still there at 20mA but i need to experiment some more.
I didnt measured the Voltage yet will do that in a few days also try to measure the gain of both vas BD139.
The test heatsink i use isnt getting hot at normal listning level.
and the final heatsinks are a litlle bit bigger.
Some good news the low Bias disortion is pretty much gone
I tested the amp again, using a testspeaker and the preout of a car radio(so no need for a a attenuator).
Installed some 4,7 Ohm savety resistors (didnt have 10 Ohm)
Adjusted Bias around 50-60 mA and offset to zero volts.
Conected the speaker and gues what? Disortion!
Measered the input signal, less than 100mV so thats not a problem.
Maybe the drivers have a super low gain? replaced the drivers with other mje15030/31, the result was still the same.
One driver was bended over so i tried to bend it back,then suddenly 30000µF discharged within a second(litle short in PSU)well atleast i was awake again
.Then i replaced the mje15030/31 with bd139/140, an the result was verry bad, verry much disortion, then i looked at the pcb again, damn diferent pins.
Turned the drivers around, repowered the amp and the result was a litle better than the begining(the BD got a litle higher gain i think).
nothing seems wrong with the drivers so there no problem.
then i replaced the Vas bd139 with another bd139, repowered the amp and.. the disortion is gone!
I need to do some better listning test but could not hear any anoying disortions at 60mA bias, they are still there at 20mA but i need to experiment some more.
I didnt measured the Voltage yet will do that in a few days also try to measure the gain of both vas BD139.
The test heatsink i use isnt getting hot at normal listning level.
and the final heatsinks are a litlle bit bigger.
So...the old and good BD139...very good to know your
.... unit is sounding nice...no problems if you wanna increase your bias...till 130 miliamps no problems...only excesses of heat.
Also details are lost too..but continue to sound good.
I hope you enjoy the amplifier...be happy man... now you got it.
" Dx amplifier, a smiling amplifier, the guarantee of satisfaction "
regards,
Carlos
.... unit is sounding nice...no problems if you wanna increase your bias...till 130 miliamps no problems...only excesses of heat.
Also details are lost too..but continue to sound good.
I hope you enjoy the amplifier...be happy man... now you got it.
" Dx amplifier, a smiling amplifier, the guarantee of satisfaction "
regards,
Carlos
Now i see why i love BD139....has never create me problems
All my life, this transistor was always solution..even beeing drivers for Radio Frequency transmitters.
And now, beeing solution for friends having problems with Dx units.
Well....VAS are already BD139...and drivers are TIP41/42....those will work fine too.
The polarity inversion is common too...reason why i have posted images of the BD139...and i have made it twice...unfortunattelly people has not patience to read entire thread.
This behavior seems too much strange to me, as i have readed the entire forum two times...even those bad educated post and those "figther groups" that use to discuss details of electrons spinning clockwise or inverted....now i am in the third readings.
regards,
Carlos
All my life, this transistor was always solution..even beeing drivers for Radio Frequency transmitters.
And now, beeing solution for friends having problems with Dx units.
Well....VAS are already BD139...and drivers are TIP41/42....those will work fine too.
The polarity inversion is common too...reason why i have posted images of the BD139...and i have made it twice...unfortunattelly people has not patience to read entire thread.
This behavior seems too much strange to me, as i have readed the entire forum two times...even those bad educated post and those "figther groups" that use to discuss details of electrons spinning clockwise or inverted....now i am in the third readings.
regards,
Carlos
Macd...i forgot to say, but it is a good idea to increase R6 too.
As blue current and red current will flow into R6, and to avoid heat into the zener, it is a good idea to increase this resistor, as shown in dark blue, to 2700 ohms..... if you find a 3000 ohms resistance, will be even better.
3300 ohms is not a very good idea.
regards,
Carlos
As blue current and red current will flow into R6, and to avoid heat into the zener, it is a good idea to increase this resistor, as shown in dark blue, to 2700 ohms..... if you find a 3000 ohms resistance, will be even better.
3300 ohms is not a very good idea.
regards,
Carlos
Attachments
Have tried the increase of bias?
Increase it to 100 miliamps and try once again
regards,
Carlos
.......................................................................................................
Graham
Yes, i agree...enormous difference in gain distribute the VBEs very bad..the upper transistor is saturating in advance because it has differences in gain.
Bias will fix this.
regards,
Carlos
Increase it to 100 miliamps and try once again
regards,
Carlos
.......................................................................................................
Graham
Yes, i agree...enormous difference in gain distribute the VBEs very bad..the upper transistor is saturating in advance because it has differences in gain.
Bias will fix this.
regards,
Carlos
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