There are some people in our area who make transformer winding as their business. They are not torroidal transformers but E-I types. I am planning to have them assemble a transformer for me. What do you thinks is the specification I need to have. I mean how many amperes of transformer and the secondary AC voltage do I need to achieve about 65-70VDC using the PSU board for DX turbo by alexmm.
Those informations are posted into this same thread
http://www.diyaudio.com/forums/showthread.php?postid=1550293#post1550293
It is a good idea to read the thread in advance to assemble amplifiers.
regards,
Carlos
http://www.diyaudio.com/forums/showthread.php?postid=1550293#post1550293
It is a good idea to read the thread in advance to assemble amplifiers.
regards,
Carlos
Oh!... this one is there only to provide low impedance to high frequencies
the voltage will face will be milivolts into the differential input... and audio voltage will be 1 volt or sligtly more than that.
You can use the smaller you find.... those 104, made of ceramic, used into portable radios.... search for it into a circuit junk yard or your own junk box.... voltage there is minimum... the smaller capacitor will fit.
This capacitor is there only because electrolitic condensers are constructed alike a coil... and coil has inductances...and inductances opposes to high frequency to cross, to enter the circuit...so.... this is another way... another street... another patch to allow high frequencies to cross in a more "confortable" way.
The one you have will fit..... use the one you have.. and values can be 100n to 1uf.... any value will be good..... adjust it to the size you have into the board...and do not worry, be happy!
regards,
Carlos
the voltage will face will be milivolts into the differential input... and audio voltage will be 1 volt or sligtly more than that.
You can use the smaller you find.... those 104, made of ceramic, used into portable radios.... search for it into a circuit junk yard or your own junk box.... voltage there is minimum... the smaller capacitor will fit.
This capacitor is there only because electrolitic condensers are constructed alike a coil... and coil has inductances...and inductances opposes to high frequency to cross, to enter the circuit...so.... this is another way... another street... another patch to allow high frequencies to cross in a more "confortable" way.
The one you have will fit..... use the one you have.. and values can be 100n to 1uf.... any value will be good..... adjust it to the size you have into the board...and do not worry, be happy!
regards,
Carlos
looks huge and powefull!
You gonna be happy..... i hope will work first power on moment,
It is very normal to have construction errors....check everything three times before apply power.
Do not apply power without protective resistances in series with rails ... both rails..... then measure the potencial drop over those resistances and divide the value obtained (expressed in volts... where 980 milivolts you may write 0.98V) by the resistance value you are using.
I use 10 ohms and 10 watts...but off course you can use other values...in my case...those 0.98V will result in 98 miliamperes each rail...they measure different... positive rail use to measure sligtly higher current value because of the zener diode power consumption you have into the input circuitry.
You can use the value you have...3.3 ohms, 4.7 ohms, 5 ohms, 8.2 ohms, 10 ohms, 12 ohms, 15 ohms, 18 ohms, 22 ohms, 27 ohms, 33 ohms, 47 ohms, 56 ohms, 68 ohms ,82 ohms and 100 ohms.
Swith power on without any speaker connected into the output, as you may have off set... and sometimes errors made during construction will give you full rail voltage into the output... and sometimes much more than that.... this is an "emergency alarm" that informs you you have made mistakes during construction...check transistors position first.... them shorts into the board second... then missed parts third.... take a look at your supply polarity and supply voltage too.
Audio amplifiers measure small off set into the ouput... DC voltage there use to be very low.. around 3 milivolts... maximum allowable by tradition is 25 miliamperes.... higher voltage into the output seems errors into the circuit... assembly errors, human errors, mistakes..... also non adjustable bias seems errors into the bias circuit... also too much high or too much low bias indicates errors... bias circuit adjustment must operate always... tweaking trimpot you must have changes into the current (voltage over resistance) measurements.... good off set and small bias adjustment (around 100 miliamperes) seems the amplifier is fine.
Last test is to check oscilation... plug your multimeter into the output, Alternated voltage scale higher than 2 volts.... you must measure nothing.... if found AC voltage..hehehehe..oscilations man.. errors or smaller capacitors into the compensation (lag ones... Miller one)
I have made several... it is plug and play....BUT.... we use to produce mistakes... this is more normal...much normal than to see first time succeded people.
Use fuses into the ouput line and into the rails.... there's a chart with current and power informations in this same thread.
Never switch a power amplifier "on" without good heatsinks attached to the power transistors..... normal operation voltage goes from 41 to 52 degrées celsius..... this amplifier uses a very big heatsink.... 10 by 10 centimeters of aluminium to each 10 watts RMS of continuous, steady tone, power.... so.... 100 watts continuous (musical need less than half of that) needs heatsink area exposed to the air equivalent of 10 plates of aluminium, each one with 10 centimeters side if squared..... smaller can be used of course...but carefull with your volume knob...use fan to help during hot weather days and do not use steady tones continuous testing for long time.
If your speaker is small and not very strong....heheheh.. say bye bye to him in advance to use this powerfull machine.
be happy.... this way i gonna be happy too!
Carlos
You gonna be happy..... i hope will work first power on moment,
It is very normal to have construction errors....check everything three times before apply power.
Do not apply power without protective resistances in series with rails ... both rails..... then measure the potencial drop over those resistances and divide the value obtained (expressed in volts... where 980 milivolts you may write 0.98V) by the resistance value you are using.
I use 10 ohms and 10 watts...but off course you can use other values...in my case...those 0.98V will result in 98 miliamperes each rail...they measure different... positive rail use to measure sligtly higher current value because of the zener diode power consumption you have into the input circuitry.
You can use the value you have...3.3 ohms, 4.7 ohms, 5 ohms, 8.2 ohms, 10 ohms, 12 ohms, 15 ohms, 18 ohms, 22 ohms, 27 ohms, 33 ohms, 47 ohms, 56 ohms, 68 ohms ,82 ohms and 100 ohms.
Swith power on without any speaker connected into the output, as you may have off set... and sometimes errors made during construction will give you full rail voltage into the output... and sometimes much more than that.... this is an "emergency alarm" that informs you you have made mistakes during construction...check transistors position first.... them shorts into the board second... then missed parts third.... take a look at your supply polarity and supply voltage too.
Audio amplifiers measure small off set into the ouput... DC voltage there use to be very low.. around 3 milivolts... maximum allowable by tradition is 25 miliamperes.... higher voltage into the output seems errors into the circuit... assembly errors, human errors, mistakes..... also non adjustable bias seems errors into the bias circuit... also too much high or too much low bias indicates errors... bias circuit adjustment must operate always... tweaking trimpot you must have changes into the current (voltage over resistance) measurements.... good off set and small bias adjustment (around 100 miliamperes) seems the amplifier is fine.
Last test is to check oscilation... plug your multimeter into the output, Alternated voltage scale higher than 2 volts.... you must measure nothing.... if found AC voltage..hehehehe..oscilations man.. errors or smaller capacitors into the compensation (lag ones... Miller one)
I have made several... it is plug and play....BUT.... we use to produce mistakes... this is more normal...much normal than to see first time succeded people.
Use fuses into the ouput line and into the rails.... there's a chart with current and power informations in this same thread.
Never switch a power amplifier "on" without good heatsinks attached to the power transistors..... normal operation voltage goes from 41 to 52 degrées celsius..... this amplifier uses a very big heatsink.... 10 by 10 centimeters of aluminium to each 10 watts RMS of continuous, steady tone, power.... so.... 100 watts continuous (musical need less than half of that) needs heatsink area exposed to the air equivalent of 10 plates of aluminium, each one with 10 centimeters side if squared..... smaller can be used of course...but carefull with your volume knob...use fan to help during hot weather days and do not use steady tones continuous testing for long time.
If your speaker is small and not very strong....heheheh.. say bye bye to him in advance to use this powerfull machine.
be happy.... this way i gonna be happy too!
Carlos
Attachments
Smaller transistors alike To220 ones, needs heatsink too.
Keep all them, the smaller ones, working with temperature bellow the human high fever temperature for safety reasons.
Transistors when overheated changes all specifications and performance..and you can have, as result, huge overheating into all your amplifier with enormous temperature drift caused by some transistors overheated.... so... the best sittuation is to "feel" them not more than 5 degrées celsius above your environment temperature.... means almost frozzen, because the temperature you have in UK those last days.
Output power will depend your supply voltage drop during strong bass reproduction..means if you have weak supply, or resistive cables and bad fuses (high resistance fuses)... and heat spots too... then if during strong current demands moments your voltage drops to 35 volts... well... no magic possible... with 35 volts your power will be not higher than 100 watts RMS.
This amplifier (all amplifiers) can be adjusted related input sensitivity... this one was made to produce full power with 750 milivolts RMS of audio entering...but you can change this if needed to have more or less sensitivity... the normal is to have 75 percent of your volume knob turned up when the amplifier starts to distorts (clipping)... this will allow you to face lower volume musics and to increase it... having room for that.... of course if your audio source puts out 2 volts you gonna have distortions and you may have to adjust audio source volume or the amplifier sensitivity (resistance in series with electrolitic condenser that comes from the second diferential base and goes to the base... reduce this resistance for more gain...increase it to reduce gain)
This amplifier can reach 500 watts RMS very easy.... God save your speaker!
regards,
Carlos
Keep all them, the smaller ones, working with temperature bellow the human high fever temperature for safety reasons.
Transistors when overheated changes all specifications and performance..and you can have, as result, huge overheating into all your amplifier with enormous temperature drift caused by some transistors overheated.... so... the best sittuation is to "feel" them not more than 5 degrées celsius above your environment temperature.... means almost frozzen, because the temperature you have in UK those last days.
Output power will depend your supply voltage drop during strong bass reproduction..means if you have weak supply, or resistive cables and bad fuses (high resistance fuses)... and heat spots too... then if during strong current demands moments your voltage drops to 35 volts... well... no magic possible... with 35 volts your power will be not higher than 100 watts RMS.
This amplifier (all amplifiers) can be adjusted related input sensitivity... this one was made to produce full power with 750 milivolts RMS of audio entering...but you can change this if needed to have more or less sensitivity... the normal is to have 75 percent of your volume knob turned up when the amplifier starts to distorts (clipping)... this will allow you to face lower volume musics and to increase it... having room for that.... of course if your audio source puts out 2 volts you gonna have distortions and you may have to adjust audio source volume or the amplifier sensitivity (resistance in series with electrolitic condenser that comes from the second diferential base and goes to the base... reduce this resistance for more gain...increase it to reduce gain)
This amplifier can reach 500 watts RMS very easy.... God save your speaker!
regards,
Carlos
Remember... I'm a Destroyer... and X (Extra)
So i know we do such things.
No one has burned more transistors than i did!
My amplifiers are real "macho" amplifiers...made to real man...has to hold strong job, heavy duty..shorts and high power during long time...to be sure.. i use to enter sinus full power, sometimes distorted, over 2 ohms to see if will burn transistors.
ahahahaha..... sometimes burns!... then i use to increase them in number......NO!... VI limiter is a crime...negative to use limiters!
regards,
Carlos
So i know we do such things.
No one has burned more transistors than i did!
My amplifiers are real "macho" amplifiers...made to real man...has to hold strong job, heavy duty..shorts and high power during long time...to be sure.. i use to enter sinus full power, sometimes distorted, over 2 ohms to see if will burn transistors.
ahahahaha..... sometimes burns!... then i use to increase them in number......NO!... VI limiter is a crime...negative to use limiters!
regards,
Carlos
Attachments
Destroyer threads and amplifiers are protected by the "shape"
No Boring folks use to "land" into my threads (the ones i use to open).... Destroyer have an extra protection.... that protude!... the radar cup you see in white into the Destroyer ship.
You see, this is a sign for them..... entering here, bothering, may face the "protector"
I use to invite them to seat.........................you know, to take a chair......hehehehe
Carlos
No Boring folks use to "land" into my threads (the ones i use to open).... Destroyer have an extra protection.... that protude!... the radar cup you see in white into the Destroyer ship.
You see, this is a sign for them..... entering here, bothering, may face the "protector"
I use to invite them to seat.........................you know, to take a chair......hehehehe
Carlos
Attachments
Nico Has is a very nice guy... much appreciated inside my heart and mind
Nice folk... interesting ideas.... good amplifiers... clever man.... good one!
But you are very old Lineup?.... ahahahhaa..... i have born in 1951 but i am only a nice powerfull 5.7 litters engine... will never reach such age.... unaceptable!
I think you should avoid too much sun dear lineup... observing your avatar seems you were too much under the sun...maybe new Obama style.... very nice guy Obama... finally my US friends are rid from "that one".... the garden's bush.... cemitery plants.
regards,
Carlos
Nice folk... interesting ideas.... good amplifiers... clever man.... good one!
But you are very old Lineup?.... ahahahhaa..... i have born in 1951 but i am only a nice powerfull 5.7 litters engine... will never reach such age.... unaceptable!
I think you should avoid too much sun dear lineup... observing your avatar seems you were too much under the sun...maybe new Obama style.... very nice guy Obama... finally my US friends are rid from "that one".... the garden's bush.... cemitery plants.
regards,
Carlos
You see Joka... i love to help.
About bias adjustment... stand by current adjustment.
I have perceived sonic advantages when we tweak this bias adjustment while playing music... i have perceived that we have a better point... alike to tune something.
Year ago, when i decide to try simulator, i found the fourier analisis results is sensitive to stand by adjustment... distortion can be reduced tweaking the bias..... so... there are optimized adjustment points... i found two...one very near the threshold.. when the output transistors are near to be cutted and another one, even better with some current...more than 100 miliamperes in many amplifiers.
Well, good fourrier results does not guarantee good sound by itself...but if we can reduce it,... why not to reduce.... the audio quality will tell you what is good for your ears.. sometimes this represents excelent fourier analisis results and sometimes not.
A good idea, as starting point, is to check voltage over the power transistors emitters.... if the one is conducting (a very good idea), you gonna have few milivolts over this resistance.... keep it low... 1 miliampere is enougth to each transistor... having many you will have many miliamperes only into the output units.
This is a method to check your adjustment...as the bias should "force" all transistors to conduct... drivers and output units..all them!..... but tweaking for more than that... while listening...may be a good idea.
tweak using the protective resistances.... do it very low power... 1 watt maximum...only something around 3 AC volts going to the speaker.. and listen with attention, in special trebles and deep basses... carefull not to adjust too further, increasing too much your bias not to burn your protective resistances and not to reduce your amplifier supply voltage too much, as this will create more problems, more troubles than solutions for you.
Having troubles to do that...just follow the basic instructions to adjust amplifiers, measuring over protective resistances and check if all transistors are "ON"...if not, then increase till all them are on... check the total bias once again..if bigger than 200 miliamperes..then you have problems into your output and drivers.. mistakes into connections or defective untis.
regards,
Carlos
About bias adjustment... stand by current adjustment.
I have perceived sonic advantages when we tweak this bias adjustment while playing music... i have perceived that we have a better point... alike to tune something.
Year ago, when i decide to try simulator, i found the fourier analisis results is sensitive to stand by adjustment... distortion can be reduced tweaking the bias..... so... there are optimized adjustment points... i found two...one very near the threshold.. when the output transistors are near to be cutted and another one, even better with some current...more than 100 miliamperes in many amplifiers.
Well, good fourrier results does not guarantee good sound by itself...but if we can reduce it,... why not to reduce.... the audio quality will tell you what is good for your ears.. sometimes this represents excelent fourier analisis results and sometimes not.
A good idea, as starting point, is to check voltage over the power transistors emitters.... if the one is conducting (a very good idea), you gonna have few milivolts over this resistance.... keep it low... 1 miliampere is enougth to each transistor... having many you will have many miliamperes only into the output units.
This is a method to check your adjustment...as the bias should "force" all transistors to conduct... drivers and output units..all them!..... but tweaking for more than that... while listening...may be a good idea.
tweak using the protective resistances.... do it very low power... 1 watt maximum...only something around 3 AC volts going to the speaker.. and listen with attention, in special trebles and deep basses... carefull not to adjust too further, increasing too much your bias not to burn your protective resistances and not to reduce your amplifier supply voltage too much, as this will create more problems, more troubles than solutions for you.
Having troubles to do that...just follow the basic instructions to adjust amplifiers, measuring over protective resistances and check if all transistors are "ON"...if not, then increase till all them are on... check the total bias once again..if bigger than 200 miliamperes..then you have problems into your output and drivers.. mistakes into connections or defective untis.
regards,
Carlos
Hi carlos,
im building dhr turbo and the dx amp. i have purchased some of the parts... but the problem is the capacitors 22nf, 270nf 27nf or any of the capacitors on your design rated in nanofarad....
here in our place nano farad capacitors are not avalable... wat shall i do? i already purchased 70% DHR turbo parts and for stereo...
any replacement in pico farad?
thanx
Riche
im building dhr turbo and the dx amp. i have purchased some of the parts... but the problem is the capacitors 22nf, 270nf 27nf or any of the capacitors on your design rated in nanofarad....
here in our place nano farad capacitors are not avalable... wat shall i do? i already purchased 70% DHR turbo parts and for stereo...
any replacement in pico farad?
thanx
Riche
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