"Floating" ground
Carlos,
Thanks for your reply.
My term "floating ground" was probably not the correct term to use. Perhaps I should have called it "floating secondary", because the power supply itself is grounded.
This is shown in the jpeg attachment. Would you kindly look and give you assessment now that the picture is more complete?
Thanks,
Francois
Carlos,
Thanks for your reply.
My term "floating ground" was probably not the correct term to use. Perhaps I should have called it "floating secondary", because the power supply itself is grounded.
This is shown in the jpeg attachment. Would you kindly look and give you assessment now that the picture is more complete?
Thanks,
Francois
Attachments
Hi F,
that does not work.
You must tie the power supply zero volts back to the centre tap of the transformer secondary. But you don't have a centre tap!!!
that does not work.
You must tie the power supply zero volts back to the centre tap of the transformer secondary. But you don't have a centre tap!!!
Exactly this one you are showing me
Please, do not use it dear François, or do not use it with my baby beautifull amplifier, please!
I know some brands use this way..... but do that with those brands please, and let my baby working into a more safe way.
Or do it under your risk.
Not a very good idea my friend.
regards,
Carlos
Please, do not use it dear François, or do not use it with my baby beautifull amplifier, please!
I know some brands use this way..... but do that with those brands please, and let my baby working into a more safe way.
Or do it under your risk.
Not a very good idea my friend.
regards,
Carlos
Re: Exactly this one you are showing me
Carlos, thanks; also to Andrew.
The verdict is in -- I will not use it this way with Carlos' baby.
Regards,
Francois
destroyer X said:
Carlos, thanks; also to Andrew.
The verdict is in -- I will not use it this way with Carlos' baby.
Regards,
Francois
I really thank you my dear...let my baby work into a more standard way.
thank you.
regards,
Carlos
thank you.
regards,
Carlos
Regulated supply?
Would the baby compromise for a regulated supply like in the attached?
I have tested my transformer -- after rectification it can deliver +80 0 -80VDC (loaded) @ ~ 8 amps. (Max is 17 amps but I have not tested VAC at that current)
Then regulate that for a 70 0 -70VD supply, like Nordic. Also re-read comments/changes about a Precision on a +/-70 V supply.
Would Precision be happy with this arrangement?
Regards,
Francois
Would the baby compromise for a regulated supply like in the attached?
I have tested my transformer -- after rectification it can deliver +80 0 -80VDC (loaded) @ ~ 8 amps. (Max is 17 amps but I have not tested VAC at that current)
Then regulate that for a 70 0 -70VD supply, like Nordic. Also re-read comments/changes about a Precision on a +/-70 V supply.
Would Precision be happy with this arrangement?
Regards,
Francois
Attachments
hi Francois G,
The "basic" circuit looks right to me, but what regulators are you going to use?
Have you thought about the power dissapation of the regulators, (Vdc - Vreg) x current ?
regards
The "basic" circuit looks right to me, but what regulators are you going to use?
Have you thought about the power dissapation of the regulators, (Vdc - Vreg) x current ?
regards
Thanks Greg. Currently I don't have a regulator design, but a suitable design should be easy to find. (The AudioXpress magizine's had a PC board for regulators used with Adcom 555 amps (200W/200W) which should work here.) Do you have a regulator design to recommend?
The regulator heat dissipation is something I will account for in my heatsinks (big!). The regulator pass resistor(s) will be mounted on the same heatsink as the Precision PC. I will probably add a fan to help at high power.
Regards,
Francois
The regulator heat dissipation is something I will account for in my heatsinks (big!). The regulator pass resistor(s) will be mounted on the same heatsink as the Precision PC. I will probably add a fan to help at high power.
Regards,
Francois
Here is one supply, Dx Regulator this one
It is an Ampex alike design made in the seventies, also used by Sony Corporation for long time.... that topologie, other values and some overcurrent protections and some crown bars used too...huge supplies worked in large videotape machines those years.
I have used them to Radio Amateur transceivers, entering 24 VDC and adjusting to 13.8 and 30 amperes into 5 percent voltage error (voltage loss, voltage drop).... only 390 watts supply..but i have build to test the Precision..... i have not appreciated the sound and i give up.
A good idea to read a little bit more my dear friend...all this was published, the supply, the test, the comments and everything was already discussed and posted.
The circuit is reliable, and works fine, stabilization needs some tuning but goes from 3 to 10 percent, depending the transistors used and the voltage adjusted compared to the input voltage.
If you enter with 80 volts simetrical, you can adjust to 64 in the place the seventy volts used by Nordic...he did that because he had not the regulator and had the supplyes to use...he joined two Dx Standard amplifier supplies together that resulted that voltage.
The Precision was designed to 64 volts, and God bless the one that will have the courage to open full volume of this little monster amplifier...very strong man...can make powerholic very satisfied with the power using the standard 64 volts.
You can adjust 64 volts, and three transistors up and 3 transistors down will make the job to you...the series power ones
can use 2SC5200 and 2SA1943 or others powerfull units you have...because 400 watts will circulate, and it is safe to install 3 units to each rail as series pass transistors...drivers can be 2SC4793 and complementary, 2SA1837... also for error amplifier the same transistors can be used...heatsinks into the drivers, better to go together the output heatsink.
Because of this reduction of voltage...from 80 volts unstable to 64 volts stable you will have 16 volts and a lot of amperes entering the series pass rail transistors.... 3 units in parallel each rail.. and emitter equalizing resistors are not a bad idea to them.
This will need enormous heatsink to hold the power... that will be the current multiplied by the voltage drop over the series transistors... and two channels into sucking energy from the same supply, under 4 ohms loads.
The salvation is because the supply will go down...under load the voltage will go 69 volts for sure...and this means you will have only 5 volts multiplied by the current, to each rail current, when two channels will be driven full power simultaneously and this will reduce the heat...you may be able, even to reduce your output units quantity if you want....but not a very good idea.
The idea is to use your transformer...but something expensive, enormous cost, another enormous heatsink, a lot of transistors more and i have found the audio quality, using electronic supplies not very good..... i found the passive supplies better in sonics.
Well.... your decision, it is up to you...i think, if you wanna know, that the use of your supply will create much more problems than solutions to your life.. it is not a good idea.
But, if you want....be happy...pleasure in life is very important...better than money, and sometimes some stupid things make us very happy...why not to try.
Be happy, but please, let my baby survive, be beloved amplifier..use 64 volts and please, forget that idea to use regulators..
Here is one... Democracy is this way...i do not like, i think it is not a good idea, i think the sound is not good..but even this way i am trying to help you.
regards,
Carlos
It is an Ampex alike design made in the seventies, also used by Sony Corporation for long time.... that topologie, other values and some overcurrent protections and some crown bars used too...huge supplies worked in large videotape machines those years.
I have used them to Radio Amateur transceivers, entering 24 VDC and adjusting to 13.8 and 30 amperes into 5 percent voltage error (voltage loss, voltage drop).... only 390 watts supply..but i have build to test the Precision..... i have not appreciated the sound and i give up.
A good idea to read a little bit more my dear friend...all this was published, the supply, the test, the comments and everything was already discussed and posted.
The circuit is reliable, and works fine, stabilization needs some tuning but goes from 3 to 10 percent, depending the transistors used and the voltage adjusted compared to the input voltage.
If you enter with 80 volts simetrical, you can adjust to 64 in the place the seventy volts used by Nordic...he did that because he had not the regulator and had the supplyes to use...he joined two Dx Standard amplifier supplies together that resulted that voltage.
The Precision was designed to 64 volts, and God bless the one that will have the courage to open full volume of this little monster amplifier...very strong man...can make powerholic very satisfied with the power using the standard 64 volts.
You can adjust 64 volts, and three transistors up and 3 transistors down will make the job to you...the series power ones
can use 2SC5200 and 2SA1943 or others powerfull units you have...because 400 watts will circulate, and it is safe to install 3 units to each rail as series pass transistors...drivers can be 2SC4793 and complementary, 2SA1837... also for error amplifier the same transistors can be used...heatsinks into the drivers, better to go together the output heatsink.
Because of this reduction of voltage...from 80 volts unstable to 64 volts stable you will have 16 volts and a lot of amperes entering the series pass rail transistors.... 3 units in parallel each rail.. and emitter equalizing resistors are not a bad idea to them.
This will need enormous heatsink to hold the power... that will be the current multiplied by the voltage drop over the series transistors... and two channels into sucking energy from the same supply, under 4 ohms loads.
The salvation is because the supply will go down...under load the voltage will go 69 volts for sure...and this means you will have only 5 volts multiplied by the current, to each rail current, when two channels will be driven full power simultaneously and this will reduce the heat...you may be able, even to reduce your output units quantity if you want....but not a very good idea.
The idea is to use your transformer...but something expensive, enormous cost, another enormous heatsink, a lot of transistors more and i have found the audio quality, using electronic supplies not very good..... i found the passive supplies better in sonics.
Well.... your decision, it is up to you...i think, if you wanna know, that the use of your supply will create much more problems than solutions to your life.. it is not a good idea.
But, if you want....be happy...pleasure in life is very important...better than money, and sometimes some stupid things make us very happy...why not to try.
Be happy, but please, let my baby survive, be beloved amplifier..use 64 volts and please, forget that idea to use regulators..
Here is one... Democracy is this way...i do not like, i think it is not a good idea, i think the sound is not good..but even this way i am trying to help you.
regards,
Carlos
Hello,
Maybe one day, Carlos will collect all and take note to publish his thesis " Creation and evolution of several amplifier based on common work ".
I remind in the Ancient Greek, when someone is sick, all the people who see the poor man is allowed to give his advice to help him.
Sometimes, the patient lose a leg because people have decided this is the best way to cure his eczema or something alike.
😎
Maybe one day, Carlos will collect all and take note to publish his thesis " Creation and evolution of several amplifier based on common work ".
I remind in the Ancient Greek, when someone is sick, all the people who see the poor man is allowed to give his advice to help him.
Sometimes, the patient lose a leg because people have decided this is the best way to cure his eczema or something alike.
😎
Well dear Max, here i use to find high level people
Even the young boys, here in this forum, International young guys, American (US) boys and European guys too.... they use to show more know how than many engineers i could find in my country.
It is very interesting the psychology connected to the audio fanatics, their beliefs, their needs and how their brain works....in other words, their subjective brain programing, alike the software used...ahahahahah.
People needs.... the power..... the way we try to have power, as a solution of our existance.
The mythic search for magic and mistery, the special parts, the unobtanium and those beliefs.
My people do not believe in unobtanium...their know how is so small that even that stuff cannot enter their brain...with some exceptions.... i am talking about the big mass of people.... the more common people, the majority of people that has interest in electronics.
Here i could have an Engineer, yesterday, asking if can use a transistor he has in his junk box...he found the data sheet and asked me if can use it.... was a darlington, not a normal output transistor we use into output...we use darlington discrete connection, not a single darlington unit into the output because we cannot adjust driver's emitter resistance, because it goes internally related the chip that constitutes the transistor die...also the power was small...that darlington could dissipate only 75 watts, when needed, minimum, is 150 watts to the Dx Standard Amplifier.... you see...an engineer could not recognize, and electronic engineer could not recognize the darlington was not good enougth...he had the data sheet and sent to me to answer him the question:
Can this fit into the Dx Standard?
Here, in our forum, i can write a book.... and this is not difficult, i think everybody here can do that, showing the interesting behavior we have.... there are a lot of strange personalities, characters, behaviors that can result in a very interesting book.
There's a place in Europe that people likes stands to listen music..if not using stands, the sound is no good for them...enormous stands, some of them very heavy, and everybody using stands to put speaker into the ears level...good that..but tweeter has dispersion, has angle, and even into the floor as billions of people use, can be listened..also high into the ceiling can be used too....installed inside walls..... but there are milions that believe the stand is better...so..they construct nice things. made using metal, and some of them put stones, sand an other heavy material to avoid ressonances..they want to avoid construction floor ressonances...very intelligent the idea, but do not know how much this works, as the whole world has not perceive that need...very strange and unusual i think.
Unfortunattely, the chapter related my own people would be so sad that i would remove from the book.... the ignorance is so deep, here in my place, that you could cry reading something made based into the local knowledge about electronics.
All i know was learned burning transistors, trying, into a try and error basis.... those last 4 years i had developed myself a lot, those 4 years had 30 times the value of the other 43 years building amplifiers, i have learned a lot into the forum...i am the forum result, a product that born into the forum... i have a good part of forum knowlege.
This is not too much, into forum level i am average, or lower than that...but here, i think i will not find more than 10 guys that can compete, about knowledge, with me.... this is very sad... i had not a college formation, a college, Universitary Education in Electronics and i am "eating into the breakfast".... laughing and easy, experienced engineers here.... i am not proud with that...i am really very, very, very sad about that.
There are high school boys that knows more than i know....and in my place i am in the top...so.... you see the difference.
Now i can see what means third world...it is clear to me... sadly.
regards,
Carlos
Even the young boys, here in this forum, International young guys, American (US) boys and European guys too.... they use to show more know how than many engineers i could find in my country.
It is very interesting the psychology connected to the audio fanatics, their beliefs, their needs and how their brain works....in other words, their subjective brain programing, alike the software used...ahahahahah.
People needs.... the power..... the way we try to have power, as a solution of our existance.
The mythic search for magic and mistery, the special parts, the unobtanium and those beliefs.
My people do not believe in unobtanium...their know how is so small that even that stuff cannot enter their brain...with some exceptions.... i am talking about the big mass of people.... the more common people, the majority of people that has interest in electronics.
Here i could have an Engineer, yesterday, asking if can use a transistor he has in his junk box...he found the data sheet and asked me if can use it.... was a darlington, not a normal output transistor we use into output...we use darlington discrete connection, not a single darlington unit into the output because we cannot adjust driver's emitter resistance, because it goes internally related the chip that constitutes the transistor die...also the power was small...that darlington could dissipate only 75 watts, when needed, minimum, is 150 watts to the Dx Standard Amplifier.... you see...an engineer could not recognize, and electronic engineer could not recognize the darlington was not good enougth...he had the data sheet and sent to me to answer him the question:
Can this fit into the Dx Standard?
Here, in our forum, i can write a book.... and this is not difficult, i think everybody here can do that, showing the interesting behavior we have.... there are a lot of strange personalities, characters, behaviors that can result in a very interesting book.
There's a place in Europe that people likes stands to listen music..if not using stands, the sound is no good for them...enormous stands, some of them very heavy, and everybody using stands to put speaker into the ears level...good that..but tweeter has dispersion, has angle, and even into the floor as billions of people use, can be listened..also high into the ceiling can be used too....installed inside walls..... but there are milions that believe the stand is better...so..they construct nice things. made using metal, and some of them put stones, sand an other heavy material to avoid ressonances..they want to avoid construction floor ressonances...very intelligent the idea, but do not know how much this works, as the whole world has not perceive that need...very strange and unusual i think.
Unfortunattely, the chapter related my own people would be so sad that i would remove from the book.... the ignorance is so deep, here in my place, that you could cry reading something made based into the local knowledge about electronics.
All i know was learned burning transistors, trying, into a try and error basis.... those last 4 years i had developed myself a lot, those 4 years had 30 times the value of the other 43 years building amplifiers, i have learned a lot into the forum...i am the forum result, a product that born into the forum... i have a good part of forum knowlege.
This is not too much, into forum level i am average, or lower than that...but here, i think i will not find more than 10 guys that can compete, about knowledge, with me.... this is very sad... i had not a college formation, a college, Universitary Education in Electronics and i am "eating into the breakfast".... laughing and easy, experienced engineers here.... i am not proud with that...i am really very, very, very sad about that.
There are high school boys that knows more than i know....and in my place i am in the top...so.... you see the difference.
Now i can see what means third world...it is clear to me... sadly.
regards,
Carlos
Re: Here is one supply, Dx Regulator this one
Carlos,
Many thanks for the "DX regulator" schematic - It will be used some day. But for the Precision you have persuade me - no more regulators!
Now I need a new transformer for 46-0-46 V - have any of you North American builders found a good source of 46VAC CT transformers?
Regards,
Francois
destroyer X said:
Carlos,
Many thanks for the "DX regulator" schematic - It will be used some day. But for the Precision you have persuade me - no more regulators!
Now I need a new transformer for 46-0-46 V - have any of you North American builders found a good source of 46VAC CT transformers?
Regards,
Francois
Hi Carlos
I don't quite understand how that regulator circuit works.
It looks like the adjustment would be very sensitive with no emitter resistor on the feedback transistor. If the pot wiper is adjusted to below Vz +0.6V, the feedback transistor is off, but above Vz +0.6V, that transistor will saturate and the result would be a series pass zener regulator, unless an emitter resistor is used.
I've noticed there is one thing that simulators sometimes error, and that is allowing you to place a relatively large cap as an emitter load on the pass transistor without any current limiting resistor. I'm sure you're not one of those who rely blindly on a PC simulator, but in my real world experience, the pass transistor BJT may explode
when you power it up. A transistor once blew up in my face like a firecracker because of this; a piece of it hit me in the forehead.😱 I quickly figured out my mistake, it was one of those duhhhh moments. It's too bad we don't have simulated xsistors to build real amplifiers with.
I don't quite understand how that regulator circuit works.
It looks like the adjustment would be very sensitive with no emitter resistor on the feedback transistor. If the pot wiper is adjusted to below Vz +0.6V, the feedback transistor is off, but above Vz +0.6V, that transistor will saturate and the result would be a series pass zener regulator, unless an emitter resistor is used.I've noticed there is one thing that simulators sometimes error, and that is allowing you to place a relatively large cap as an emitter load on the pass transistor without any current limiting resistor. I'm sure you're not one of those who rely blindly on a PC simulator, but in my real world experience, the pass transistor BJT may explode
when you power it up. A transistor once blew up in my face like a firecracker because of this; a piece of it hit me in the forehead.😱 I quickly figured out my mistake, it was one of those duhhhh moments. It's too bad we don't have simulated xsistors to build real amplifiers with.
I love corn bread and chicken, and also i appreciate CBS240 very much
A nice guy, a clever scientist.
regards,
Carlos
A nice guy, a clever scientist.
regards,
Carlos
Partsexpress has good prices. I haven't bought one of the transformers, but they look decent with good pricing.
Plitron surplus/overstock is reasonable... but they are up here in Canada so shipping is a bit more trouble for you.
Plitron surplus/overstock is reasonable... but they are up here in Canada so shipping is a bit more trouble for you.
Ryan,
Thanks. I have bought a bunch of stuff from them in the past but have not checked their transformers.
Now I have checked -- PartsExpress indeed has a suitable one: Avel Y236907 800VA 45V+45V Toroidal Transformer for $90.37
Seems like a good candidate with a reasonable new price. I would be tickled if I could find something like it on the surplus market.
Regards,
Francois
Thanks. I have bought a bunch of stuff from them in the past but have not checked their transformers.
Now I have checked -- PartsExpress indeed has a suitable one: Avel Y236907 800VA 45V+45V Toroidal Transformer for $90.37
Seems like a good candidate with a reasonable new price. I would be tickled if I could find something like it on the surplus market.
Regards,
Francois
There's also Antek. Bit lower price, bit lower quality. I've used these without any problem.
http://www.toroid-transformer.com/index.html
..Todd
http://www.toroid-transformer.com/index.html
..Todd
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