The language i have read, seems that it should be somewhere near Norway.
One word....Jackaard...gave me this idea.
This circuit is interesting to Diy...it may work with 47 volts simetrical.
And will be not difficult to reach 180 Watts at 4 ohms...maybe more than a hundred watts over 8 ohms.
It is simple, beautifully bootstrapped (i like those circuits, Yamaha and Kenwood use them often now a days), do not use hard to find or expensive parts, and it seems that will produce a nice sound.
No!..i did not construct it....but i am thinking about, but first will be the Molerkamp.
Please, post your modifications suggestions, tell us if you already heard this one. how it sounds and those things.
This is all fun!
regards,
Carlos
One word....Jackaard...gave me this idea.
This circuit is interesting to Diy...it may work with 47 volts simetrical.
And will be not difficult to reach 180 Watts at 4 ohms...maybe more than a hundred watts over 8 ohms.
It is simple, beautifully bootstrapped (i like those circuits, Yamaha and Kenwood use them often now a days), do not use hard to find or expensive parts, and it seems that will produce a nice sound.
No!..i did not construct it....but i am thinking about, but first will be the Molerkamp.
Please, post your modifications suggestions, tell us if you already heard this one. how it sounds and those things.
This is all fun!
regards,
Carlos
Attachments
not easy to tell anything
we dont know name of amp
we dont know who designed
we dont know any websource
we only know a schematic with some missing data
might be your own drawing, circuit even ....
Carlos
If you want some input
you have to give me a little more to refer to
At least if you want my opinion
regards
lineup
Oh my dear Line up...i am in the same position as you are, knowing nothing about.
I was in the WEB surffing and trying to have different PC power supply schematics when some new power amplifiers schematics appeared....because i have typed POWER supplyes....and they appear, as they are power.
I know the same as you know...just offering to people that want to try, or know something to make comments, or tell us what they feel observing the schematic.
Those things.
I cannot tell you anything my dear...i am sorry for that.
regards,
Carlos
I was in the WEB surffing and trying to have different PC power supply schematics when some new power amplifiers schematics appeared....because i have typed POWER supplyes....and they appear, as they are power.
I know the same as you know...just offering to people that want to try, or know something to make comments, or tell us what they feel observing the schematic.
Those things.
I cannot tell you anything my dear...i am sorry for that.
regards,
Carlos
I've seen the schematic in several places and that is one of them :
http://www.pablin.com.ar/electron/circuito/audio/amp260/index.htm
I had always been wondering why it nees no idling currrent adjustment? I think it's related to this also :
http://www.brunt.de/KE/Elektronik/280W_Verstaerker/280W_Verstaerker.htm
Is it really good for the power it claims to provide?
http://www.pablin.com.ar/electron/circuito/audio/amp260/index.htm
I had always been wondering why it nees no idling currrent adjustment? I think it's related to this also :
http://www.brunt.de/KE/Elektronik/280W_Verstaerker/280W_Verstaerker.htm
Is it really good for the power it claims to provide?
Very good...every information about it is welcome.
The 82 ohms resistor can be substituted by a trimpot (100 ohms) to adjust the bias.
They made this way as will work with 99 percent of the parts used...those three diodes will produce 1.8 volts....0.6 volts each one, and the resistor will increase into 3.6 volts, that will be interesting.
I think that will be more intersting to use 5 diodes and the trimpot, as will be needed 1.8 volts positive and 1.8 volts negative related the output line...biasing all those transistors adequately.
The sittuation in the schematic may underbiased that output units.
Also i think that those darlingtons need 220 picofarads (minimum) from colector to base to avoid oscilations.
Carlos
The 82 ohms resistor can be substituted by a trimpot (100 ohms) to adjust the bias.
They made this way as will work with 99 percent of the parts used...those three diodes will produce 1.8 volts....0.6 volts each one, and the resistor will increase into 3.6 volts, that will be interesting.
I think that will be more intersting to use 5 diodes and the trimpot, as will be needed 1.8 volts positive and 1.8 volts negative related the output line...biasing all those transistors adequately.
The sittuation in the schematic may underbiased that output units.
Also i think that those darlingtons need 220 picofarads (minimum) from colector to base to avoid oscilations.
Carlos
Hey, this is actually a VAS bootstrapped in both ends. It improves transistor linearity altough not as much as cascoding, while still providing rail to rail output. However, while the VAS strongly benefits from that, the linearity of the input LTP is reduced unless it's cascoded.
Involved components are 270ohm 1W resistor, 47uF 40V capacitor, 100 ohm resistor, and 47nF capacitor. The latter is required to prevent oscillation due to positive miller feedback at RF, and I know because I have tried it and I ran into the same pitfalls.
Output resistors are .47 ohm but the "." appears to be lost due to low-quality image conversion.
Involved components are 270ohm 1W resistor, 47uF 40V capacitor, 100 ohm resistor, and 47nF capacitor. The latter is required to prevent oscillation due to positive miller feedback at RF, and I know because I have tried it and I ran into the same pitfalls.
Output resistors are .47 ohm but the "." appears to be lost due to low-quality image conversion.
Carlos,
only you have shown up those schematics here on diya with light-blue background, isn't it so that you are trying to construct an amplifier and just want fool to us with the originator because you want others opinion without make a fool of your self?
Or else where did you find it, please give us the adress to the greate source of yours!
The circuit have one bootstrapp for driver and output stage, the other botsrapp on the low side is counteracting both LTP and VAS BD139, is this good???
And those miller cap on both side to rail is not good for PSRR!
If they are added to prevent oscillation it would be better to add base stoppers to output transistors first.
Cheers Michael
only you have shown up those schematics here on diya with light-blue background, isn't it so that you are trying to construct an amplifier and just want fool to us with the originator because you want others opinion without make a fool of your self?
Or else where did you find it, please give us the adress to the greate source of yours!
The circuit have one bootstrapp for driver and output stage, the other botsrapp on the low side is counteracting both LTP and VAS BD139, is this good???
And those miller cap on both side to rail is not good for PSRR!
If they are added to prevent oscillation it would be better to add base stoppers to output transistors first.
Cheers Michael
Upupa Epops said:Carlos, you have rare talent, still find again and again " stone age " connections...
I think a little bit of "back to the stone age - attitude" is always quite healthy. For example, modern circuits do perform better but they tend to be very complex. Complexity causes issues that might actually start to degrade performance. Constant current sources and other "modern" stuff are nice but the increased performance that they bring isn't really THAT huge. In my opinion, the circuit that Carlos posted is after a bit of tweaking a very good performer in some applications where too much modernism just isn't worth it.
Finally, here's some food for thought: I ran a ltspice simulation of bootstrapped quasi complementary stage and a ccs symmetric complementary stage. Sort of a "stone age" vs. "modern" test, though not 100% reliable... Attached is the FFT graph of both amps when they clip mildly. Green graph is the bootstrapped circuit.
Teemu K
Attachments
When someone say that friend A is nice, this do not means that all others are not!
So, it will be more precise to observe the words, as if you try to make analisis, will have a lot of possibilities....and having doubts, best to ask the thread opener what he meant about the thread...or what is the intention, if not already explained.
Of course, in this thread, there's no intention to fool no one...as we humans already do that with ourselves continuously...and this is more than enougth.
When you switch amplifiers on, you perceive a lot of defects.... in a matter of minutes you will not perceive anymore....brain adjustment where made...and we think that the amplifier enter the stabilizing period!...there are people that keep them switched on for half hour to stabilize, or to burn adequately some component..... if listening during the burn in...you will perceive the changes in audibility as a result of burn in...when the brain made.
If you do not listen during the burn in....you go to listen after the burn in period, and will imagine that "it is not already burned!"..this is some example, that many of us, used to fool ourselves.
I think, this is enougth...that we already do those things, having because of that, wrong evaluation about a lot of things...continuous listening will modify the amplifiers sonics qualities....was not because the amplifier "changed"...it is because our brain produced "adjustements".
The schematic was posted to show you, forum guys, the amplifier i have found....it seems i saw it by the first time...but i cannot guarantee if this is really true...as i made hundreds of amplifiers, this one could already have beeing reproducing music in my home....i am not sure, as i have not notes of everything i made since 1969.... remembering some, and the notes made related the numericall sequence...the construction numbers where memorized, and checked by around 3 construction each week...the minimun production i ever made in my life...when sick or very lazy week.
What do to with the schematic, well, your decision guys....i already made mine decision, that can be modified, depending group acceptance or rejection related this unit.
Someone very clever already perceived that i use to paint blue the schematics "to be constructed"...and that i use border colors codes of thickness and color to my priority list..... done to myself, but if blue is positive things to you to...join the blue guys club Man!...i love blue!.
Negative that color or code had intentions to induce this or that...well, this is hard to induce guys this way...i am not so competent...but thank you, the one that may imagined that.
Amplifier was posted to show..... if you decide to:
Make deep analisis.....good!
To modiy it .................good!
Just to watch it...........good!
To criticise it................good!
To smash it.................also good...i did not have designed the unit!
To fix error...................Excelent!
Maybe i will move my priority sequence of construction, depending the evaluation posted by many good guys, that may produce comments that may have stong sense to me.
It is good to remember, that our words, human words, do not have second to third of fouth of fifth hidden intentions always.
It can have adressed, of course, but this is more exception than a rule...because defensive mechanisms, that all of us use all time long, can modify your message intention.
Example:
Moderator X is fast in the trigger
This can be understood as criticism or that i am sending him a prize related competence...if defended guy, the moderator X, will always understand the prize...if Paranoid, will perceive as criticism.
So, codified messages can have many possible translations...here you could see only two.....but can have much more...so....this do not works...as you can tell the guy.."goooood!"..and the guy turn not happy with you....and the oposite, you can be telling "baaaad"...and the guys will feel pride of his competence.
Boy!..i was just surffing the web!...i was searching for Switching power supplies schematics, and because the world "power" those two amplifiers published...one of North Europe and the other Gorilla, was found.
I decide to show guys.....intention, to show guys...painted blue to remember me to construct it.
Just that.
Simple this way.
Direct and objective...other things are our deliriums....imagination only.(deliriums from delirating)
Thank you all, by the attention to read and to comment, this is kind from you...thanks for Epupa, AndrewT, Eva, Ultima Thule, Teemuk and Darkferinz.
Of course i am listening you...reading you, and collecting informations, opinnions, feelings, related the amplifier.
regards,
Carlos
So, it will be more precise to observe the words, as if you try to make analisis, will have a lot of possibilities....and having doubts, best to ask the thread opener what he meant about the thread...or what is the intention, if not already explained.
Of course, in this thread, there's no intention to fool no one...as we humans already do that with ourselves continuously...and this is more than enougth.
When you switch amplifiers on, you perceive a lot of defects.... in a matter of minutes you will not perceive anymore....brain adjustment where made...and we think that the amplifier enter the stabilizing period!...there are people that keep them switched on for half hour to stabilize, or to burn adequately some component..... if listening during the burn in...you will perceive the changes in audibility as a result of burn in...when the brain made.
If you do not listen during the burn in....you go to listen after the burn in period, and will imagine that "it is not already burned!"..this is some example, that many of us, used to fool ourselves.
I think, this is enougth...that we already do those things, having because of that, wrong evaluation about a lot of things...continuous listening will modify the amplifiers sonics qualities....was not because the amplifier "changed"...it is because our brain produced "adjustements".
The schematic was posted to show you, forum guys, the amplifier i have found....it seems i saw it by the first time...but i cannot guarantee if this is really true...as i made hundreds of amplifiers, this one could already have beeing reproducing music in my home....i am not sure, as i have not notes of everything i made since 1969.... remembering some, and the notes made related the numericall sequence...the construction numbers where memorized, and checked by around 3 construction each week...the minimun production i ever made in my life...when sick or very lazy week.
What do to with the schematic, well, your decision guys....i already made mine decision, that can be modified, depending group acceptance or rejection related this unit.
Someone very clever already perceived that i use to paint blue the schematics "to be constructed"...and that i use border colors codes of thickness and color to my priority list..... done to myself, but if blue is positive things to you to...join the blue guys club Man!...i love blue!.
Negative that color or code had intentions to induce this or that...well, this is hard to induce guys this way...i am not so competent...but thank you, the one that may imagined that.
Amplifier was posted to show..... if you decide to:
Make deep analisis.....good!
To modiy it .................good!
Just to watch it...........good!
To criticise it................good!
To smash it.................also good...i did not have designed the unit!
To fix error...................Excelent!
Maybe i will move my priority sequence of construction, depending the evaluation posted by many good guys, that may produce comments that may have stong sense to me.
It is good to remember, that our words, human words, do not have second to third of fouth of fifth hidden intentions always.
It can have adressed, of course, but this is more exception than a rule...because defensive mechanisms, that all of us use all time long, can modify your message intention.
Example:
Moderator X is fast in the trigger
This can be understood as criticism or that i am sending him a prize related competence...if defended guy, the moderator X, will always understand the prize...if Paranoid, will perceive as criticism.
So, codified messages can have many possible translations...here you could see only two.....but can have much more...so....this do not works...as you can tell the guy.."goooood!"..and the guy turn not happy with you....and the oposite, you can be telling "baaaad"...and the guys will feel pride of his competence.
Boy!..i was just surffing the web!...i was searching for Switching power supplies schematics, and because the world "power" those two amplifiers published...one of North Europe and the other Gorilla, was found.
I decide to show guys.....intention, to show guys...painted blue to remember me to construct it.
Just that.
Simple this way.
Direct and objective...other things are our deliriums....imagination only.(deliriums from delirating)
Thank you all, by the attention to read and to comment, this is kind from you...thanks for Epupa, AndrewT, Eva, Ultima Thule, Teemuk and Darkferinz.
Of course i am listening you...reading you, and collecting informations, opinnions, feelings, related the amplifier.
regards,
Carlos
well this circuit does not surprise me. I have modified
a lot of this kind in my state college days when my
electronics and communications engineering college mates
made this as their project
I'd rather use transistorized VBE multipliers which are more accurate.
rectifier diodes used are just real slow swiching affecting soundstage quality.
though this topology is still in used in a french audio amplifier
manufaturer, PSS (profesional sound systems).
Old does not automatically mean bad.
Also... to some extend simple can be beautiful (as long as simple is not the only goal). Components, which are not in the circuit do not cause trouble.
But in fact I would tend to implement several changes.
1. TIP140/145 are darlingtons. With some more idle current in the VAS you can skip the DB139/140 driver stage.
2. I would prefer a Vbe multiplier for thermal compensation of the output stage.
3. Yes, of course emitter resistors in the output stage of 47 Ohms are a typing error as Eva already pointed out.
4. I don't like the brute force frequency compensation.
My trials would go to the direction to get rid of the compensation caps from rail to base at the output stage.
Furtheron I would try to optimize HF phase margin with some lead compensation in the VAS. And then put one dominant pole.
I.e. a cap between both bases of the differential, this also avoids
TIM distorsion at fast transient input signals.
...OK, this compensation philosphy is just grey theory so far and often I most accept that the real circuit teaches you different, but at least I would try my way first...
5.
There is one general oscillation reason, which often is ignored:
Inductance of DC rails, it usually is bringing great improvements to have small E-caps from + to - directly at the collectors of the output stage. You can use two caps in series and connect the center tap to GND. But more important is that the HF path from between NPN collector to PNP has a low impedance at high frequencies. I usuall tend to use 47uF ...150uF for each pair of output devices, directly connected to the collectors. (Additional paralleled film or cermamic caps are nice from theory, but in my pratical tests their influence was neglectible.)
Also... to some extend simple can be beautiful (as long as simple is not the only goal). Components, which are not in the circuit do not cause trouble.
But in fact I would tend to implement several changes.
1. TIP140/145 are darlingtons. With some more idle current in the VAS you can skip the DB139/140 driver stage.
2. I would prefer a Vbe multiplier for thermal compensation of the output stage.
3. Yes, of course emitter resistors in the output stage of 47 Ohms are a typing error as Eva already pointed out.
4. I don't like the brute force frequency compensation.
My trials would go to the direction to get rid of the compensation caps from rail to base at the output stage.
Furtheron I would try to optimize HF phase margin with some lead compensation in the VAS. And then put one dominant pole.
I.e. a cap between both bases of the differential, this also avoids
TIM distorsion at fast transient input signals.
...OK, this compensation philosphy is just grey theory so far and often I most accept that the real circuit teaches you different, but at least I would try my way first...
5.
There is one general oscillation reason, which often is ignored:
Inductance of DC rails, it usually is bringing great improvements to have small E-caps from + to - directly at the collectors of the output stage. You can use two caps in series and connect the center tap to GND. But more important is that the HF path from between NPN collector to PNP has a low impedance at high frequencies. I usuall tend to use 47uF ...150uF for each pair of output devices, directly connected to the collectors. (Additional paralleled film or cermamic caps are nice from theory, but in my pratical tests their influence was neglectible.)
Hellô guys, Hienrich and Chocoholic....thank you
Hienrich amplifier is pretty.....i was watching it yesterday.
Choco.....i see you are living in Asia now......the best for you in your business Choco.
I will travel to Brasilia, the Central Federal Government, i will be "out of the air" for some hours.
Thank you to post your feeling here.
regards,
Carlos
Hienrich amplifier is pretty.....i was watching it yesterday.
Choco.....i see you are living in Asia now......the best for you in your business Choco.
I will travel to Brasilia, the Central Federal Government, i will be "out of the air" for some hours.
Thank you to post your feeling here.
regards,
Carlos
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