Yes SNG001...but for a while..it is dangerous to have lower voltage there
When the power amplifier output voltage swing reach the maximum negative..then the voltage at this bootstrap condenser will be at - 30 volts (because supply drop voltages and output saturation voltage in the power transistors reduce the swing to almost that or even less)..... well.... the negative side in this electrolitic condenser will be "charged" with -30 volts referenced to the ground potential (zero)...the positive has around +20 volts...so... the total voltage may reaach 50 or more volts.... for safety reasons we double this...but 50 volts insulating one may work without problems.
Why may work without troubles without open a hole in the insulating dieletric material?....because condensers usually can hold more 20 percent than the voltage painted in the plastic cover.... this is made because factory enginners are clever and prevent such kind of things...as our mains can change the voltage for plus and minus 20 percent..also the rectified voltage can increase a lot....so, it is more safe to a 50 volts electrolitic condenser be able to face 60 or more volts... reason why they are underrated..... your 50 volts condenser is a 63V or more in the reality.
Do it... and be happy...but early future, having the higher insulating voltage one..better to replace it.... this is only a safety decision.... in the real world..you may die because old and your amplifier will be operating, without problems, with a 50 volts condenser installed there... also people, usually do not use full power....so..the swing will be withing 40 volts peak to peak almost 90 percent of the time... half power more or less.
Welcome..... i have special appreciation on Aussies...i think they are most latine people (heart and mind) between the englanders.
Andrew T is rigth... he use to be when the problem is connected to rules and calculations.... NP condenser is really a waste... you can even use the standard.... i have installed this way because i have several of those ones here....it is there because people loves to install some special parts... and this drives some folks confident the sound will be special because special parts there..so..some "politically correct" decisions are usually taken.
I will love the sunny day my dear friend AndrewT start to talk, also, the good things applied to our designs.... we want to have some positive things too...the points we got a good decision should be pointed too.
regards,
Carlos
When the power amplifier output voltage swing reach the maximum negative..then the voltage at this bootstrap condenser will be at - 30 volts (because supply drop voltages and output saturation voltage in the power transistors reduce the swing to almost that or even less)..... well.... the negative side in this electrolitic condenser will be "charged" with -30 volts referenced to the ground potential (zero)...the positive has around +20 volts...so... the total voltage may reaach 50 or more volts.... for safety reasons we double this...but 50 volts insulating one may work without problems.
Why may work without troubles without open a hole in the insulating dieletric material?....because condensers usually can hold more 20 percent than the voltage painted in the plastic cover.... this is made because factory enginners are clever and prevent such kind of things...as our mains can change the voltage for plus and minus 20 percent..also the rectified voltage can increase a lot....so, it is more safe to a 50 volts electrolitic condenser be able to face 60 or more volts... reason why they are underrated..... your 50 volts condenser is a 63V or more in the reality.
Do it... and be happy...but early future, having the higher insulating voltage one..better to replace it.... this is only a safety decision.... in the real world..you may die because old and your amplifier will be operating, without problems, with a 50 volts condenser installed there... also people, usually do not use full power....so..the swing will be withing 40 volts peak to peak almost 90 percent of the time... half power more or less.
Welcome..... i have special appreciation on Aussies...i think they are most latine people (heart and mind) between the englanders.
Andrew T is rigth... he use to be when the problem is connected to rules and calculations.... NP condenser is really a waste... you can even use the standard.... i have installed this way because i have several of those ones here....it is there because people loves to install some special parts... and this drives some folks confident the sound will be special because special parts there..so..some "politically correct" decisions are usually taken.
I will love the sunny day my dear friend AndrewT start to talk, also, the good things applied to our designs.... we want to have some positive things too...the points we got a good decision should be pointed too.
regards,
Carlos
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The reason why, dear Tinitus, he is doing what i have asked him to do
To avoid to start a big and never ending discussion about capacitors, alike happened in several threads, along these last 6 years.
He is beeing kind, friendly and cooperative with the thread opener...respecting his friend's will, not beeing unkind....seems to me, and also looks it seems to him to, this is not against forum rules..to be friendly and cooperative and to follow some advises from old forum folks alike i am.
Friendship and respect use to generate better results..these ones are kind have from me all attention, to answer whatever they want to know (if i can of course)... by direct mailing i can answer whatever they need...so...they will not be without answer...only avoiding to go off topic.
This is the reason Tinitus..some friends try to do what we ask them to do.
I am gratefull by their respect, their kindness, their cooperation, to avoid to start a long of topic conversation about condensers and capacitors.
Earth magnetic lines may drive us different Tinitus..we think opposed as i could see several times...this is good...turns forum more interesting, as there are several points of view..maybe the earth magnetic field...North part or earth and south part of earth.... in common we have is that we like violin
Be happy.
Carlos
To avoid to start a big and never ending discussion about capacitors, alike happened in several threads, along these last 6 years.
He is beeing kind, friendly and cooperative with the thread opener...respecting his friend's will, not beeing unkind....seems to me, and also looks it seems to him to, this is not against forum rules..to be friendly and cooperative and to follow some advises from old forum folks alike i am.
Friendship and respect use to generate better results..these ones are kind have from me all attention, to answer whatever they want to know (if i can of course)... by direct mailing i can answer whatever they need...so...they will not be without answer...only avoiding to go off topic.
This is the reason Tinitus..some friends try to do what we ask them to do.
I am gratefull by their respect, their kindness, their cooperation, to avoid to start a long of topic conversation about condensers and capacitors.
Earth magnetic lines may drive us different Tinitus..we think opposed as i could see several times...this is good...turns forum more interesting, as there are several points of view..maybe the earth magnetic field...North part or earth and south part of earth.... in common we have is that we like violin
Be happy.
Carlos
Attachments
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Thanks guy,
Thanks for the explanation.
I have checked the usual suspects for electronics components, they don't stock 100V electrolytics. It is expensive to order just a couple of capacitors over the web. I am using 28VAC transformer so I will test the amp with 50V bipolar cap. I may try another retailer (Wagner) later on.
- Stanley
Thanks for the explanation.
I have checked the usual suspects for electronics components, they don't stock 100V electrolytics. It is expensive to order just a couple of capacitors over the web. I am using 28VAC transformer so I will test the amp with 50V bipolar cap. I may try another retailer (Wagner) later on.
- Stanley
Yamaha uses several channels feeded by a single supply
Yamaha amplifiers supply voltage drops bellow 30 volts when these several amplifiers are operating.
When an amplifier operates with 30 volts...and the bootstrap circuit is using this same 30 volts (sometimes is lower, from a regulator)...the boostrap condenser will face around 15 volts at the positive terminal.... the maximum swing voltage, the maximum negative swing..the maximum possible (supply negative voltage limit) is 30 volts negative.
This 30 volts negative will appear at the output line, where the boostrapp condenser has it's negative lead connected....so.... the voltage in the negative side will be - 30 volts (that moment..the negative swing will charge the condenser this way)...the positive is stable...or more stable..almost fixed in 15 volts, or 20 volts...so...maximum voltage will be 50 volts (-30 added to +20V).
So...it is fine...it is all rigth..nothing strange there.
We, forum people, diyers, audiophiles, we try to make better..to go to the safe side...some supplies can have more than 35 volts... the AC mains can increase 20 percent... this results in 42.5 volts in the supply output... now imagine the supply is huge and does not drop the voltage!.... them the negative swing, that cannot be bigger than the supply rail voltage (usually is smaller) can go to -42.5 (less of course)....and positive voltage in the boostrap condenser, in the Dx Amplifiers, use to be 20 volts...so.... the condenser gonna face 62V.
In the real world..a 50V condenser can work under 62V....but.... some folks feel unsafe this way...so..condenser suggested is 100 volts..this will face all kind of possibilities/changes, to face tragedies my dear friend.
I really think the 35 volts there was a mistake from the one has drawn the circuit...it is dangerous this way...or...the voltage will drop down to 35 volts more or less..this is possible when the transformer is not big enougth to feed several channels... i have some transformers here that can drop 30 percent...and when feeding a single amplifeir operating 4 ohms...now imagine to feed 6 channels.
regards,
Carlos
Yamaha amplifiers supply voltage drops bellow 30 volts when these several amplifiers are operating.
When an amplifier operates with 30 volts...and the bootstrap circuit is using this same 30 volts (sometimes is lower, from a regulator)...the boostrap condenser will face around 15 volts at the positive terminal.... the maximum swing voltage, the maximum negative swing..the maximum possible (supply negative voltage limit) is 30 volts negative.
This 30 volts negative will appear at the output line, where the boostrapp condenser has it's negative lead connected....so.... the voltage in the negative side will be - 30 volts (that moment..the negative swing will charge the condenser this way)...the positive is stable...or more stable..almost fixed in 15 volts, or 20 volts...so...maximum voltage will be 50 volts (-30 added to +20V).
So...it is fine...it is all rigth..nothing strange there.
We, forum people, diyers, audiophiles, we try to make better..to go to the safe side...some supplies can have more than 35 volts... the AC mains can increase 20 percent... this results in 42.5 volts in the supply output... now imagine the supply is huge and does not drop the voltage!.... them the negative swing, that cannot be bigger than the supply rail voltage (usually is smaller) can go to -42.5 (less of course)....and positive voltage in the boostrap condenser, in the Dx Amplifiers, use to be 20 volts...so.... the condenser gonna face 62V.
In the real world..a 50V condenser can work under 62V....but.... some folks feel unsafe this way...so..condenser suggested is 100 volts..this will face all kind of possibilities/changes, to face tragedies my dear friend.
I really think the 35 volts there was a mistake from the one has drawn the circuit...it is dangerous this way...or...the voltage will drop down to 35 volts more or less..this is possible when the transformer is not big enougth to feed several channels... i have some transformers here that can drop 30 percent...and when feeding a single amplifeir operating 4 ohms...now imagine to feed 6 channels.
regards,
Carlos
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Carlos is not doing the voltage math right.
With 50V rails, no more than 25V will be applied to the bootstrap capacitor during normal operation.
On the other hand, if for some reason the output of the amplifier sticks to the negative rail, the 3.3k resistor will limit the current available to damage the capacitor to approx 22mA or less (assuming the capacitor breaks down at 25V or more). This means only 0.5W available to damage the capacitor, so no fireworks this time, only heat, it may take hours to vent.
I used to include a zener in my bootstrapped VAS to provide regulation and make VAS biasing and capacitor stress not dependent on supply voltage.
Any sensible designer would use a 25V or 35V capacitor, as in Yamaha schematic.
With 50V rails, no more than 25V will be applied to the bootstrap capacitor during normal operation.
On the other hand, if for some reason the output of the amplifier sticks to the negative rail, the 3.3k resistor will limit the current available to damage the capacitor to approx 22mA or less (assuming the capacitor breaks down at 25V or more). This means only 0.5W available to damage the capacitor, so no fireworks this time, only heat, it may take hours to vent.
I used to include a zener in my bootstrapped VAS to provide regulation and make VAS biasing and capacitor stress not dependent on supply voltage.
Any sensible designer would use a 25V or 35V capacitor, as in Yamaha schematic.
Recieved my boards from vokker they so tiny and very good quality🙂.
Unfortuntaley i was following the 1.5c schematic only to realise it not the matching board have to take out all the resistors lucky not soldered.
Vokker which schemtaic i follow for the boards you gave me??
can you give me link to download it.
Unfortuntaley i was following the 1.5c schematic only to realise it not the matching board have to take out all the resistors lucky not soldered.
Vokker which schemtaic i follow for the boards you gave me??
can you give me link to download it.
You really have to ask Volker and Rudi...i have no more these old versions
But they were, all them, posted in this same thread.... have just to search for them.
In Greg Home page only the last version (1.5) and also in my computer only the last version.
They should have, as they're using old versions...also they like the old version the most.
I have several amplifiers, but all them were modified to the last version, the ST.
I do like older versions too...but they are less stable, and i have the obligation to suggest the most stable one.
It is playing here, connected to my computer... all day long playing music... and doing that for more than a week.... each day i love it more... each music i discover new details i have never listened before...so.... i am very satisfied and i hope you gonna like it too.
regards,
Carlos
But they were, all them, posted in this same thread.... have just to search for them.
In Greg Home page only the last version (1.5) and also in my computer only the last version.
They should have, as they're using old versions...also they like the old version the most.
I have several amplifiers, but all them were modified to the last version, the ST.
I do like older versions too...but they are less stable, and i have the obligation to suggest the most stable one.
It is playing here, connected to my computer... all day long playing music... and doing that for more than a week.... each day i love it more... each music i discover new details i have never listened before...so.... i am very satisfied and i hope you gonna like it too.
regards,
Carlos
The issues is will the board be compatible with the 1.5c schematic as it is diffrent layout and i dont wnat to follow a 1.5c scheme only to have it go up in smoke due to mismatch of components.
Modifications made was mainly the removal of capacitors
a resistance that had the value increased and the insertion of a emitter resistance in the first Vas stage..... so.... you can remove parts in the same board...also you can substitute a resistance using the same board...but to include a series resistance in the second VAS emitter you have to cut a copper track and to solder a resistance below the board.
This compatibility depends your personal evaluation...if a track cutted and a resistance soldered below the board is considered by you alike a "assembling line adjustments", then the board is compatible...... of course if you think this is "too much" to make in a so beautifull board...then it is not compatible.
I think it is compatible, my personnal and subjective evaluation.... but i understand that different people has different needs, there are more demanding people than i am.
regards Joka.
Carlos
a resistance that had the value increased and the insertion of a emitter resistance in the first Vas stage..... so.... you can remove parts in the same board...also you can substitute a resistance using the same board...but to include a series resistance in the second VAS emitter you have to cut a copper track and to solder a resistance below the board.
This compatibility depends your personal evaluation...if a track cutted and a resistance soldered below the board is considered by you alike a "assembling line adjustments", then the board is compatible...... of course if you think this is "too much" to make in a so beautifull board...then it is not compatible.
I think it is compatible, my personnal and subjective evaluation.... but i understand that different people has different needs, there are more demanding people than i am.
regards Joka.
Carlos
Hey,
I used schematic-version 1.3 and assembled with layout-version 1.4c. That´s the same one, a little bit confusing with this versionsnumbers...
Here is the workingcopy.
Why so many versions (including minor changes that go back and forth) of a circuit that uses less than 100 parts?
I got a much more complex (800 parts) commercial product ready within 4 PCB revisions.
I got a much more complex (800 parts) commercial product ready within 4 PCB revisions.
Oh, I thought "the more the merrier" ....with DX, I think Im up about maybe 100 different layout versions 😀 tho I wanted the fun of making boards, now I may decide to go for the optimum....hardwired
Eva, ofcourse you are better and more effective....being a pro you should be
Eva, ofcourse you are better and more effective....being a pro you should be
Hi Tinni, Eva
I guess Carlos is elsewhere at the moment.
You know, I think it's clear that there are many people contributing to the design and all would like to feel that they can have a part in the process. In fact, this design (ES) was largely completed some time ago. It is still only1.3.
We had ST up to 1.5 but that project is now proceeding to A class and different revisions apply.
Sure, There are some details being discussed, mainly basic queries but this is social activity more than revision.
I have spent some years in commercial laboratories, doing R&D work. There, as in most technical manufacturing businesses, are several guys in a closely regimented pecking order of authority, responsibilty etc. who develop plans, designs and pass them to engineers for production and so on. Quick- smart-today! no mucking about or no job for you, pal! There it makes sense to offer nothing but a finished working model on the first iteration, fully tested and debugged next, field tested and cosmetic mods next....One austere model, another with lots of bling or way cool ......
This is the commercial world but many, here on DYI forum I think, come from or even come to escape from! hahahahaha!
It is perhaps romantic to imagine that Uncle Carlos is also inviting us to his beach apartment in Brazil to share in his life and audio experiences at the same time but that's fine by me. He says nice things about us Aussies because we both understand and love this kind of life. Maybe one one day you would like to try it a bit too-especially in your midwinter when it is 30 degrees and beautiful for us.
This is all OT, I know and I think someone is reaching for the AK47 or Uzi to use it on me but I hope you know this is not going to zip along from one careful, logical production step to another. There are many who are having 'NE555 and three resistors' kind of issues with electronics and many want to just drop these learning steps and build their own 400 watt class D or Linear right now - today! They are the ones who don't even try to put the smoke back in the semis when it fails either. They don't come back. It's in the bin and they maybe go ride moutain bikes or something.
We have to stop and encourage these guys.
If you look at the number of hits etc and when they happen, a little bit of stats will tell you what's really happening in the solid state threads. That is an interesting piece for market researchers.
Have a great day and best regards to you.
Ian
I guess Carlos is elsewhere at the moment.
You know, I think it's clear that there are many people contributing to the design and all would like to feel that they can have a part in the process. In fact, this design (ES) was largely completed some time ago. It is still only1.3.
We had ST up to 1.5 but that project is now proceeding to A class and different revisions apply.
Sure, There are some details being discussed, mainly basic queries but this is social activity more than revision.
I have spent some years in commercial laboratories, doing R&D work. There, as in most technical manufacturing businesses, are several guys in a closely regimented pecking order of authority, responsibilty etc. who develop plans, designs and pass them to engineers for production and so on. Quick- smart-today! no mucking about or no job for you, pal! There it makes sense to offer nothing but a finished working model on the first iteration, fully tested and debugged next, field tested and cosmetic mods next....One austere model, another with lots of bling or way cool ......
This is the commercial world but many, here on DYI forum I think, come from or even come to escape from! hahahahaha!
It is perhaps romantic to imagine that Uncle Carlos is also inviting us to his beach apartment in Brazil to share in his life and audio experiences at the same time but that's fine by me. He says nice things about us Aussies because we both understand and love this kind of life. Maybe one one day you would like to try it a bit too-especially in your midwinter when it is 30 degrees and beautiful for us.
This is all OT, I know and I think someone is reaching for the AK47 or Uzi to use it on me but I hope you know this is not going to zip along from one careful, logical production step to another. There are many who are having 'NE555 and three resistors' kind of issues with electronics and many want to just drop these learning steps and build their own 400 watt class D or Linear right now - today! They are the ones who don't even try to put the smoke back in the semis when it fails either. They don't come back. It's in the bin and they maybe go ride moutain bikes or something.
We have to stop and encourage these guys.
If you look at the number of hits etc and when they happen, a little bit of stats will tell you what's really happening in the solid state threads. That is an interesting piece for market researchers.
Have a great day and best regards to you.
Ian
Value for C18?
Carlos,
What is the value for C18?
Checking the BOM (page 4) on the latest v1.5B pdf file, it states that the C18 is a 2.2uF film cap and this does not agree with the schematics.
- Stanley
Carlos,
What is the value for C18?
Checking the BOM (page 4) on the latest v1.5B pdf file, it states that the C18 is a 2.2uF film cap and this does not agree with the schematics.
- Stanley
Thank you Ian Finch... that's the spirit... amateur and DIY
To share my beaches and to enjoy life...you've got it.
I feel happy when people build and like it...if electrons spins clockwise or counter clockwise, or some detail is not perfect... nobody cares...they want to dance...to feel good..this is what matters...the rest is rest.
Others are negative and want to suffer...well.... their problem!
regards,
Carlos
To share my beaches and to enjoy life...you've got it.
I feel happy when people build and like it...if electrons spins clockwise or counter clockwise, or some detail is not perfect... nobody cares...they want to dance...to feel good..this is what matters...the rest is rest.
Others are negative and want to suffer...well.... their problem!
regards,
Carlos
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