are they effective?
Explain, using simple words, how they work.
An orkut friend asked me and then i realised that i do not know.... or do not remember....also, after 50 years. if have not interested me, seems to me i could leave without them....seems not very important.
I can imagine protection if you invert polarity.....supply polarity and audio polarity, then it will drain,
I have tested in the simulator and was a disgrace!....seems something very bad that had more annoyng effects than the opposite.
Can you explain me?..... without complicate (my) mind with high level mathematics?....say...explaining in a such way people (average) can understand?
Yes..... i do not know everything, for sure there are things you can contribute... I was explaining, and proving, to my Orkuy group that V/I limiters are terrible for audio reproduction and then i have faced this question.
I am asking practical answer, the theorists, and also the book copiers or book text parrots, please, translate you complication in simple words,... here a chance to you to exercise the rigth to be friendly, cooperative, fair, kind and helpfull.
think on me as an audiot or a school children....so question was posted to you, as a chance to be frindly and to help, not to get another big chance to be snobish or bad.....evil guys, please..... Revertere ad locum tum (go back to the cemetery)
regards,
Carlos
Explain, using simple words, how they work.
An orkut friend asked me and then i realised that i do not know.... or do not remember....also, after 50 years. if have not interested me, seems to me i could leave without them....seems not very important.
I can imagine protection if you invert polarity.....supply polarity and audio polarity, then it will drain,
I have tested in the simulator and was a disgrace!....seems something very bad that had more annoyng effects than the opposite.
Can you explain me?..... without complicate (my) mind with high level mathematics?....say...explaining in a such way people (average) can understand?
Yes..... i do not know everything, for sure there are things you can contribute... I was explaining, and proving, to my Orkuy group that V/I limiters are terrible for audio reproduction and then i have faced this question.
I am asking practical answer, the theorists, and also the book copiers or book text parrots, please, translate you complication in simple words,... here a chance to you to exercise the rigth to be friendly, cooperative, fair, kind and helpfull.
think on me as an audiot or a school children....so question was posted to you, as a chance to be frindly and to help, not to get another big chance to be snobish or bad.....evil guys, please..... Revertere ad locum tum (go back to the cemetery)
regards,
Carlos
I am interested, also, to know the efectiveness, the increase or decrease of
efectiveness, efficiency, when you do not connect it to output rail (maybe to drain invertions, when inverted DC appear in the output)
I could see these two ways...diodes connected to the ouput line and diodes from colector to emitter.... are there others?
The best Brazilian audio group, the lovely Orkut communitty where all folks knows how to design amplifiers (not all about as you see) will be happy with your help to our improovement.
It is a rarity when people really wants to help... those last 6 years i could see majority of snobish guys, i could learn watching figths, when people forget to control themselves when want to show they are better than others..during some "smashing", some torture session...with vain, arrogance and pride popping all around!..heheheh...i have learned a lot while they were figthing... sometimes smashing fair, nice and good friends... a pity, at least i could learn some, and this is beeing multiplied in Brazil..now a days there are several guys that knows all i could learn here!
If you intend to to this here, better to give up, the double barreled is loaded, fair moderators are watching and i will react!
Explain for me please boys, to my understanding, not to show you are very good...i know you are, all i want to know is about these diodes, what do they do there?... also if you are really kind and cooperative.
regards,
Carlos
efectiveness, efficiency, when you do not connect it to output rail (maybe to drain invertions, when inverted DC appear in the output)
I could see these two ways...diodes connected to the ouput line and diodes from colector to emitter.... are there others?
The best Brazilian audio group, the lovely Orkut communitty where all folks knows how to design amplifiers (not all about as you see) will be happy with your help to our improovement.
It is a rarity when people really wants to help... those last 6 years i could see majority of snobish guys, i could learn watching figths, when people forget to control themselves when want to show they are better than others..during some "smashing", some torture session...with vain, arrogance and pride popping all around!..heheheh...i have learned a lot while they were figthing... sometimes smashing fair, nice and good friends... a pity, at least i could learn some, and this is beeing multiplied in Brazil..now a days there are several guys that knows all i could learn here!
If you intend to to this here, better to give up, the double barreled is loaded, fair moderators are watching and i will react!
Explain for me please boys, to my understanding, not to show you are very good...i know you are, all i want to know is about these diodes, what do they do there?... also if you are really kind and cooperative.
regards,
Carlos
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Carlos,
Do you mean the diodes from output to the supply rail (in non-conducting direction of course
)? They are there to clamp the output to the supplies if the output would try to go beyond the supply as that might destroy the output transistors from overvoltage.
This could happen with pulses or high frequency signals into an inductive load. As you know, if you tried to quickly change the current that goes into an inductive load, the load 'kicks back' with a very high voltage peak because it tries to keep the current going (that's the nature of an inductor of course).
hope this helps,
jd
Hi Carlos,
They are a "safegaurd" against inductive loads causing a transient that may cause secondary breakdown of the device or failure by a sudden reverse bias again caused by inductive loads . They clamp the output (in an audio amp) to the rails, any excess energy being safely absorbed by the PSU and rail decoupling.
A bit academic I think to be honest for audio. If you are driving motors etc then fair enough, but a speaker in normal use won't generate such back emf's.
That's always been my understanding.
And how fast are these diodes anyway... you remember the old BU508D etc TV line output devices with flyback diode built in... now they are fast (the diode)
They are a "safegaurd" against inductive loads causing a transient that may cause secondary breakdown of the device or failure by a sudden reverse bias again caused by inductive loads . They clamp the output (in an audio amp) to the rails, any excess energy being safely absorbed by the PSU and rail decoupling.
A bit academic I think to be honest for audio. If you are driving motors etc then fair enough, but a speaker in normal use won't generate such back emf's.
That's always been my understanding.
And how fast are these diodes anyway... you remember the old BU508D etc TV line output devices with flyback diode built in... now they are fast (the diode)
Oh!..... thank you dearest fellows....i am gratefull to you two dear friends
Now i know and i can help my boys.
thanks a lot...really thanks a lot!
Will eat less meat dear Mooly!
MP3 audio answer is beeing prepared, rigth now, to my young students.
Uncle Charlie feels very happy, very proud, when see friendship, cooperation, and education in our lovely forum.
Thread will continue opened...ahahahah..we gonna see from now on!
Carlos
Now i know and i can help my boys.
thanks a lot...really thanks a lot!
Will eat less meat dear Mooly!
MP3 audio answer is beeing prepared, rigth now, to my young students.
Uncle Charlie feels very happy, very proud, when see friendship, cooperation, and education in our lovely forum.
Thread will continue opened...ahahahah..we gonna see from now on!
Carlos
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Lol
Yesterday was fish, today is chicken (Thai chicken) and tomorrow ? maybe moo steaks
Man!...in the simulator i have increase the input signal till i have distortions in
the output..square wave naturally....then, when i switch these diodes one...you cannot believe the mess these diodes done to the waveform ....also to the distortion measured.
Seems they are not a very good idea.
Am i wrong?... was my testing method wrong?
regards,
Carlos
the output..square wave naturally....then, when i switch these diodes one...you cannot believe the mess these diodes done to the waveform ....also to the distortion measured.
Seems they are not a very good idea.
Am i wrong?... was my testing method wrong?
regards,
Carlos
They shouldn't affect normal operation at all... you can try for real of course on one of your amps too. Nothing bad happens.
I think it's something with the simulation, have no idea why though...
Did it do it at low output levels ? What load... resistor ?
Below clipping should have no effect
I think it's something with the simulation, have no idea why though...
Did it do it at low output levels ? What load... resistor ?
Below clipping should have no effect
Was already above the threshold....maximum power...when the square wave amplitude
does not increase when you increase signal.... entering sinus and distorting till have a nice square wave, but not further beyong that input level.
Otput was combination of capacitive, resistive and inductive, Ostripper load to substitute a speaker.... i think i have made something wrong Mooly....will eat fish today Mooly, because of you, to save Cows..ahahahahah..Hake (Merluza) will be the fish.
Early morning here dear Mooly, the air is filled with a lovely smell.... bread toasted.... people here do that, they put butter and they fried the bread..sometimes they use a two piece metal thing to cover the bread that goes directly to the fire...bread is inside the metal capsule...this smells good... tastes a good Coffee with Milk.... i know English loves Tea...we love Coffee with milk, dark brown coffee with suggar...hummmmmmm, will have a tosted bread too..you are invited dear Mooly.
MooooooooooH!
regards
Carlos
does not increase when you increase signal.... entering sinus and distorting till have a nice square wave, but not further beyong that input level.
Otput was combination of capacitive, resistive and inductive, Ostripper load to substitute a speaker.... i think i have made something wrong Mooly....will eat fish today Mooly, because of you, to save Cows..ahahahahah..Hake (Merluza) will be the fish.
Early morning here dear Mooly, the air is filled with a lovely smell.... bread toasted.... people here do that, they put butter and they fried the bread..sometimes they use a two piece metal thing to cover the bread that goes directly to the fire...bread is inside the metal capsule...this smells good... tastes a good Coffee with Milk.... i know English loves Tea...we love Coffee with milk, dark brown coffee with suggar...hummmmmmm, will have a tosted bread too..you are invited dear Mooly.
MooooooooooH!
regards
Carlos
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Hi Carlos
"Why are diodes needed to protect output transistors?"
Guess what - it is because VI limiters mess up so badly!
When the VI limiter switches off the output transistor, the amplifier loses control of it's own output.
Then an inductive load can cause the amplifier's output voltage to shoot right up above the supply voltage. The diodes are needed to stop that otherwise an output transistor will be damaged.
If you do not use a protection circuit, then the diodes should not be needed.
Regards - Godfrey
"Why are diodes needed to protect output transistors?"
Guess what - it is because VI limiters mess up so badly!
When the VI limiter switches off the output transistor, the amplifier loses control of it's own output.
Then an inductive load can cause the amplifier's output voltage to shoot right up above the supply voltage. The diodes are needed to stop that otherwise an output transistor will be damaged.
If you do not use a protection circuit, then the diodes should not be needed.
Regards - Godfrey
Good Godfrey...good teacher you are.... this is the way i can understand things
this because if this and because of that, that will result in that other thing.... interesting logic chain..wonderfull.."if not using V/I limiters you do not need these diodes"...GREAT!
Nice that.
Thanks my dear.
Will control not to produce bad smells in my kitchen today, as wind is going to South Africa.
heheheheh...thanks a lot!
regards,
Carlos
this because if this and because of that, that will result in that other thing.... interesting logic chain..wonderfull.."if not using V/I limiters you do not need these diodes"...GREAT!
Nice that.
Thanks my dear.
Will control not to produce bad smells in my kitchen today, as wind is going to South Africa.
heheheheh...thanks a lot!
regards,
Carlos
Yes.... positive side up...the arrow pointing up... name is cathode i think
Pointing to the positive rail..both pointing up..the negative rail one is pointing the output line.
I think was good this way...
Thank you very much, by your attention dear Janneman.
Without diodes the signal is clean and distortion numbers drops a lot!
You see... i have tried with a single resistance as a load....and the problem, despite smaller, continues.
Well, do not worry.... i will never use V/I limiter, so, will not have problems.... also will not use these diodes too.....yws, i have tried several diodes....will now stop.... already satisfied.
In my imagination.... some decades ago i found this bad to listen.... and them i have excluded from all amplifiers i have assembled....and i forgot the reasons that have programmed my old brain this way.
regards,
Carlos
Pointing to the positive rail..both pointing up..the negative rail one is pointing the output line.
I think was good this way...
Thank you very much, by your attention dear Janneman.
Without diodes the signal is clean and distortion numbers drops a lot!
You see... i have tried with a single resistance as a load....and the problem, despite smaller, continues.
Well, do not worry.... i will never use V/I limiter, so, will not have problems.... also will not use these diodes too.....yws, i have tried several diodes....will now stop.... already satisfied.
In my imagination.... some decades ago i found this bad to listen.... and them i have excluded from all amplifiers i have assembled....and i forgot the reasons that have programmed my old brain this way.
regards,
Carlos
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What's the scale on that screen in your previous post? Can't see it on the screen shot.
Also the meters in the supply limne, are they set to current or voltage mode?
jd
20 Volts per division, meters in series, for current measurement
I thank you by the further study, but really dear Janneman, i personally ain't too much interested...all i wanted is to know what diodes do.
Will not use them, if they really distort of if i have made a mistake in my method.... really, to me this does not matters anymore.
Will not use...so, if they are good or bad, does not belong to my reality anymore.
I thank you by the attention my dear... already satisfied by several interesting answers and i'm abandoning the thread, and saying thanks and good by, because the one, the thread, has acomplished the task to instruct me.... was very nice from all of you.
Sincerity, often seems rude ... but serve to avoid misunderstandings ... all you said to me is good enougth... i am satisfied.... no more interest in further, deep studies in something i will never use.
Maybe i will be unfair related to V/I limiters, but really, V/I limiters have not heart, nor conscience, so..they will not bother about me.
I will build another amplifier now...thanks.
regards,
Carlos
I thank you by the further study, but really dear Janneman, i personally ain't too much interested...all i wanted is to know what diodes do.
Will not use them, if they really distort of if i have made a mistake in my method.... really, to me this does not matters anymore.
Will not use...so, if they are good or bad, does not belong to my reality anymore.
I thank you by the attention my dear... already satisfied by several interesting answers and i'm abandoning the thread, and saying thanks and good by, because the one, the thread, has acomplished the task to instruct me.... was very nice from all of you.
Sincerity, often seems rude ... but serve to avoid misunderstandings ... all you said to me is good enougth... i am satisfied.... no more interest in further, deep studies in something i will never use.
Maybe i will be unfair related to V/I limiters, but really, V/I limiters have not heart, nor conscience, so..they will not bother about me.
I will build another amplifier now...thanks.
regards,
Carlos
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we can also add a pair of diodes from supply rails to power ground. This is the same as diodes across the smoothing caps. The diodes limit reverse voltage across the caps to 0.7Vdc. If one polarity discharges rapidly to zero while the other cap has significant charge the diode effectively prevents reverse charging of the other polarity.
The diodes also blow the fuses if the PSU is accidentally reversed to the amp supply rails. Or the bulb tester lights up to say the diodes are drawing excess reverse current.
I tend to fit both pairs of diodes. Good insurance to reduce damage.
The diodes also blow the fuses if the PSU is accidentally reversed to the amp supply rails. Or the bulb tester lights up to say the diodes are drawing excess reverse current.
I tend to fit both pairs of diodes. Good insurance to reduce damage.
That's a pity Carlos. Several people answered your questions, and now that *we* have questions to find the cause, you go away. Not so nice!
jd
All rigth dear Janneman.... i wanted the information only..when thread goes to
theories, or seems that goes to, when theorists enters...when i feel that deep molecular, micro inspections will starts..that i will be changing parts and connections in the simulator.... and trying several options..then i use to keep distance....i dislike such kind of conversations....not a real fun to me.
But i will be here, to answer your questions, some posts more.
Your protests have been accepted gladly, because you took your time to answer me...so, to be fair i will do the same a couple of threads more..for sure others will come, and people that loves to inspect these details...and they will be better company to you.
regards,
Carlos
theories, or seems that goes to, when theorists enters...when i feel that deep molecular, micro inspections will starts..that i will be changing parts and connections in the simulator.... and trying several options..then i use to keep distance....i dislike such kind of conversations....not a real fun to me.
But i will be here, to answer your questions, some posts more.
Your protests have been accepted gladly, because you took your time to answer me...so, to be fair i will do the same a couple of threads more..for sure others will come, and people that loves to inspect these details...and they will be better company to you.
regards,
Carlos
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Well, no more questions to me?... so i will build amplifiers.
And this i know how to do, to discuss theories, or to enter such kind of conversations will expose me as an idiot...i do not understand such things.
The picture shows the way i look trying to discuss theories.... i do not know, and also i do not like..do not know if egg comes first or the chicken comes first..maybe i dislike because do not know..maybe i do not know because i dislike.
ahahahahahah!
Carlos
And this i know how to do, to discuss theories, or to enter such kind of conversations will expose me as an idiot...i do not understand such things.
The picture shows the way i look trying to discuss theories.... i do not know, and also i do not like..do not know if egg comes first or the chicken comes first..maybe i dislike because do not know..maybe i do not know because i dislike.
ahahahahahah!
Carlos
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