Hello,
I remember there is a formula to calculate the ac resistance of a choke. It will show how much advantage a choke has when being compared to the usual RC network.
I forget the formula and i am outside my country with just a basic smartphone. Because with psud software one should enter dcr of the choke and its inductance is it just this formula that this software uses to produce the graphics.
If you have two chokes with identical current rating. Both 500mH but one two ohm and the other four ohm dcr will the two ohm one work twice as good?
There is energy stored in the choke. I can imagine the lower dcr choke can release that energy quicker and a bigger inductance choke can store more?
I remember some more technical people were surprised i could use so low current rating diodes with my dddac which takes almost ONE A and has some big caps. It shows choke input really reduces the current being drawn to a nice steady line. It also reduces stress in the transformer.
Greetings Eduard
I remember there is a formula to calculate the ac resistance of a choke. It will show how much advantage a choke has when being compared to the usual RC network.
I forget the formula and i am outside my country with just a basic smartphone. Because with psud software one should enter dcr of the choke and its inductance is it just this formula that this software uses to produce the graphics.
If you have two chokes with identical current rating. Both 500mH but one two ohm and the other four ohm dcr will the two ohm one work twice as good?
There is energy stored in the choke. I can imagine the lower dcr choke can release that energy quicker and a bigger inductance choke can store more?
I remember some more technical people were surprised i could use so low current rating diodes with my dddac which takes almost ONE A and has some big caps. It shows choke input really reduces the current being drawn to a nice steady line. It also reduces stress in the transformer.
Greetings Eduard
Hello,
Construction of an input choke is more critical otherwise i could be noisy. I think the ones being noisy also relates to cost. Even without vacuüm impregnation you can one that is completely silent. Probably if it is noisy it will also work less perfect when measured.
Lots of people use the wrong kind of choke( with no airgap) that will saturate and work like a wire wound resistor and then conclude crc sounds better haha.
My friend with the Hiraga started with a 200mH 1 ohm dcr choke from the shop in Paris. It was " designed" for a 50 watt classA from the same company. Of course can be used for Hiraga too. Recently we installed the LL 2771 2,8 ohm dcr with adjusted airgap ( forget the current rating) but it must give around 500 mH or more. So more than double compared to original but also higher dcr more than double.
But original look similar to cheap Hammond ( was also not expensive!) . Lundahl must be 4 or 5 times heavier. So different league but the improvement was big ( according to my friend, i not visited him for a while)
So one of the Pass/ Hiraga builders here should try a higher quality and mH number choke.
Greetings Eduard
Construction of an input choke is more critical otherwise i could be noisy. I think the ones being noisy also relates to cost. Even without vacuüm impregnation you can one that is completely silent. Probably if it is noisy it will also work less perfect when measured.
Lots of people use the wrong kind of choke( with no airgap) that will saturate and work like a wire wound resistor and then conclude crc sounds better haha.
My friend with the Hiraga started with a 200mH 1 ohm dcr choke from the shop in Paris. It was " designed" for a 50 watt classA from the same company. Of course can be used for Hiraga too. Recently we installed the LL 2771 2,8 ohm dcr with adjusted airgap ( forget the current rating) but it must give around 500 mH or more. So more than double compared to original but also higher dcr more than double.
But original look similar to cheap Hammond ( was also not expensive!) . Lundahl must be 4 or 5 times heavier. So different league but the improvement was big ( according to my friend, i not visited him for a while)
So one of the Pass/ Hiraga builders here should try a higher quality and mH number choke.
Greetings Eduard
Hello,
Toriodal and high quality together in one transformer?
Does it have screen between primary and secondary windings?
Most of the time the two halves of the secondary windings are not the same because one is on top of the other.
You remember the r core from Selectronic? They had two coils. On each coil half of the primary voltage that you must put in series to get ,230 volt primary. On top of that 115 Volt winding there was one half of the secundary winding. So both sides exactly the same. My friend uses my old 500 VA r core in his Hiraga. A pity Selectronic did close. I dont know which R core on ebay are ok. I remember buying a lamppost in Vietnam when i had to change the power plug i saw that the wire was magnetic and very thin. Just steel wire with some copper coating. Normally cutting copper wire makes no sound, this make a ting sound. Probably not good for making an output transformer!
Greetings, Eduard
Toriodal and high quality together in one transformer?
Does it have screen between primary and secondary windings?
Most of the time the two halves of the secondary windings are not the same because one is on top of the other.
You remember the r core from Selectronic? They had two coils. On each coil half of the primary voltage that you must put in series to get ,230 volt primary. On top of that 115 Volt winding there was one half of the secundary winding. So both sides exactly the same. My friend uses my old 500 VA r core in his Hiraga. A pity Selectronic did close. I dont know which R core on ebay are ok. I remember buying a lamppost in Vietnam when i had to change the power plug i saw that the wire was magnetic and very thin. Just steel wire with some copper coating. Normally cutting copper wire makes no sound, this make a ting sound. Probably not good for making an output transformer!
Greetings, Eduard
Hello,
I was thinking more about garbage from your powerline ( 230volts) easily going from primary to secondary side in your transformer.
Some technicians started recommending so called split bobbin transformers for directly heated tubes heater circuits to achieve better isolation. One of them also sells an input choke ( Dave Slagle Intact audio) to improve things.
You must remember the Nemesis circuit from Pierre Johannet single ended solid state amp with a 40 volt toroidal power transformer used as an output transformer. This shows that they can have a nice bandwidth to transfer garbage from primary to secondary side. Nowadays many power supplies used in your house have very poor power supplies that will give lots a garbage into your powerlines and that garbage can end up in every piece of equipment connected to 230 volts ac somewhere else in your house. . Yes, some things can be filtered by various supplies but stopping it from entering the secundairy windings in your gear is much better.
Probably you have read about the old technician test with a multimeter to check for optimum position of chokes/transformers. Just google. Briefly what you do is using the coil of the choke as a kind of sensor and then check the ac reading on your meter. You send a serious current to a transformer that radiates a big amount then you check how much the Lundahl coil will pick up.
Because Lundahl basically uses the same technique for all power supply and anode chokes i took a Lundahl anode choke which was 100 Henry so would be more sensitive to pick up something than a 400mH . No matter what position the Lundahl reading all very low with two A running through the power transformer
I dont remember the results being different for parallel or series connection of the two coils. Of course you must connect them according to the Lundahl data sheet.
Greetings Eduard
I was thinking more about garbage from your powerline ( 230volts) easily going from primary to secondary side in your transformer.
Some technicians started recommending so called split bobbin transformers for directly heated tubes heater circuits to achieve better isolation. One of them also sells an input choke ( Dave Slagle Intact audio) to improve things.
You must remember the Nemesis circuit from Pierre Johannet single ended solid state amp with a 40 volt toroidal power transformer used as an output transformer. This shows that they can have a nice bandwidth to transfer garbage from primary to secondary side. Nowadays many power supplies used in your house have very poor power supplies that will give lots a garbage into your powerlines and that garbage can end up in every piece of equipment connected to 230 volts ac somewhere else in your house. . Yes, some things can be filtered by various supplies but stopping it from entering the secundairy windings in your gear is much better.
Probably you have read about the old technician test with a multimeter to check for optimum position of chokes/transformers. Just google. Briefly what you do is using the coil of the choke as a kind of sensor and then check the ac reading on your meter. You send a serious current to a transformer that radiates a big amount then you check how much the Lundahl coil will pick up.
Because Lundahl basically uses the same technique for all power supply and anode chokes i took a Lundahl anode choke which was 100 Henry so would be more sensitive to pick up something than a 400mH . No matter what position the Lundahl reading all very low with two A running through the power transformer
I dont remember the results being different for parallel or series connection of the two coils. Of course you must connect them according to the Lundahl data sheet.
Greetings Eduard
Hello,
In this link you can read some info on the Lundahl chokes.
https://www.jacmusic.com/lundahl/html/power-chokes.html
For me the best shop to buy Lundahl is in Estonia.
Dont forget Lundahl can change the airgap for you at no extra charge because they have a collection of iron and coils and when they get an order they will assemble and adjust the gap right away. Getting more mH/H is a good thing and dcr remains the same.
The info is mainly focussed on tube gear but the ideas are the same.
Greetings , Eduard
In this link you can read some info on the Lundahl chokes.
https://www.jacmusic.com/lundahl/html/power-chokes.html
For me the best shop to buy Lundahl is in Estonia.
Dont forget Lundahl can change the airgap for you at no extra charge because they have a collection of iron and coils and when they get an order they will assemble and adjust the gap right away. Getting more mH/H is a good thing and dcr remains the same.
The info is mainly focussed on tube gear but the ideas are the same.
Greetings , Eduard
Hello
https://www.lundahltransformers.com/chokes/
This is clearest listing of Lundahl high current ( filament they call them) One, the ll2771, is in the wrong part of the listing.
https://www.audiohobby.eu/et/5709-lundahl-transformers
This is where i buy my Lundahl parts.
They make some low mH hight current chokes but i would go for more mH. Of course you have to check how much current you need. It depends a lot if you have stereo amp or two mono amps.
You want a CLC or LCRC ( i think the extra RC can do extra filtering ) i am not sure if input choke will like if you put REALLY big caps with no small R in front.
You mean cap multiplier , never heard one, but i don't trust it that much.haha
If you read my other posts here you will get my ideas. Especially for choke input extra mH is good. You cannot use 10 mH for choke input it will not work as a choke input.
Greetings Eduard
https://www.lundahltransformers.com/chokes/
This is clearest listing of Lundahl high current ( filament they call them) One, the ll2771, is in the wrong part of the listing.
https://www.audiohobby.eu/et/5709-lundahl-transformers
This is where i buy my Lundahl parts.
They make some low mH hight current chokes but i would go for more mH. Of course you have to check how much current you need. It depends a lot if you have stereo amp or two mono amps.
You want a CLC or LCRC ( i think the extra RC can do extra filtering ) i am not sure if input choke will like if you put REALLY big caps with no small R in front.
You mean cap multiplier , never heard one, but i don't trust it that much.haha
If you read my other posts here you will get my ideas. Especially for choke input extra mH is good. You cannot use 10 mH for choke input it will not work as a choke input.
Greetings Eduard
Post #288 give a very good description of the challenges we face in building a quiet power supply in modern home environments. There are number of things that must be considered, and the best remedy is to filter out as much line noise as possible before it reaches the secondary windings of your power transformer.
I use a combination of cylindrical ferrite cores and line rated capacitors on the AC inlet conductors. That helps keep the higher frequency hash out of the transformers.
I use a combination of cylindrical ferrite cores and line rated capacitors on the AC inlet conductors. That helps keep the higher frequency hash out of the transformers.
Hello,
There are a lot of things plugged into your power outlets and everyone of them will have its own " disturbance pattern ". One will need another filter than the other in the worst case. If you use the wrong filter on the primary side of your audio gear you could end up with a bad sounding solution. If you know which non audio device is messing up your audio gear you could filter the supply connected to that non audio device. Your milk won't taste worse if your fridge has a serious filter installed.
Most transformers used in serious technical gear all had a screen between primary and secondary. But now even more advanced gear try to safe money on power supplies
My class D power amp with choke input uses a plus 500 va transformer made by Philips in the sixties with screen and weight is 11 kilograms , fully encapsuled from a surplus store less than 40 € . Hammond will not make something like this in Costa Rica.
Like i wrote before chokes will work forever so i think it is a good investment. If you chose them carefully you can use them in future builds again.
Copper and iron as well won't get cheaper in decades to come that is sure. One of the reasons, there are so many switching supplies being made.
Split bobbin needs no screen and is easy to make. Maybe a reason some companies started using them.
Greetings, Eduard
.
There are a lot of things plugged into your power outlets and everyone of them will have its own " disturbance pattern ". One will need another filter than the other in the worst case. If you use the wrong filter on the primary side of your audio gear you could end up with a bad sounding solution. If you know which non audio device is messing up your audio gear you could filter the supply connected to that non audio device. Your milk won't taste worse if your fridge has a serious filter installed.
Most transformers used in serious technical gear all had a screen between primary and secondary. But now even more advanced gear try to safe money on power supplies
My class D power amp with choke input uses a plus 500 va transformer made by Philips in the sixties with screen and weight is 11 kilograms , fully encapsuled from a surplus store less than 40 € . Hammond will not make something like this in Costa Rica.
Like i wrote before chokes will work forever so i think it is a good investment. If you chose them carefully you can use them in future builds again.
Copper and iron as well won't get cheaper in decades to come that is sure. One of the reasons, there are so many switching supplies being made.
Split bobbin needs no screen and is easy to make. Maybe a reason some companies started using them.
Greetings, Eduard
.
Today there is a much easier and cheaper way to get a clean voltage for audio equipment without a choke. A good example is my Le Monstre amp which has pure +/-19V but DC without any noise in the power supply and without any choke, only CRCRC and low noise regulators. This is especially true for digital audio where the interference is in the MHz range and the choke cannot help much.
I managed to do the same for my tubes, clean HV voltage without any noise and only with a low-noise regulator.
There will always be someone who will like the sound of audio with chokes, but I prefer the other way which is much better from a technical point of view.
I managed to do the same for my tubes, clean HV voltage without any noise and only with a low-noise regulator.
There will always be someone who will like the sound of audio with chokes, but I prefer the other way which is much better from a technical point of view.
Attachments
We are not arguing which solution is the best, we are just considering another way, the old fashion one.
In many occasions, we return to the old fashion way after having been distracted by some fresh tricks...
Hello France,
As you probably know the French did a lost of studies about power supplies in that famous magazine but who can read French nowadays? Some people already have trouble reading their own language and NO Google translate probably cannot translate that magazine because it was not easy reading. ( I remember reading that the " le monstre with the traditional power supply mangue les yeux ( as in a well made soup)compared with the car batteries power supply and that the first one wasn't exactly instant soup.
What will Google translate do with this?
They have tried lots of supplies with many of their products and somehow they always went back to the traditional style supply.
Sure some things have evolved but why we are building a 40 year old design then?
Some people say, chokes are from the past when caps were small. BUT a big transformer and big rectifier and a tray full of caps is asking for trouble. You need some filtering because your rectifier and transformer will go crazy.
Doede the designer of the famous DDDAC uses first class regulation but also uses a big choke in a CLC setting.
There are also designs with supercaps, solid state regulation and still a choke because as the designer says the solid state regulation cannot do everything well.
AND with a true choke input you can do something that no other supply can do. Most of my supplies are choke input and some of them also use shunt regulation. I have had two devices that used sealed lead batteries.
It is up to every individual what they use.
Greetings Eduard
As you probably know the French did a lost of studies about power supplies in that famous magazine but who can read French nowadays? Some people already have trouble reading their own language and NO Google translate probably cannot translate that magazine because it was not easy reading. ( I remember reading that the " le monstre with the traditional power supply mangue les yeux ( as in a well made soup)compared with the car batteries power supply and that the first one wasn't exactly instant soup.
What will Google translate do with this?
They have tried lots of supplies with many of their products and somehow they always went back to the traditional style supply.
Sure some things have evolved but why we are building a 40 year old design then?
Some people say, chokes are from the past when caps were small. BUT a big transformer and big rectifier and a tray full of caps is asking for trouble. You need some filtering because your rectifier and transformer will go crazy.
Doede the designer of the famous DDDAC uses first class regulation but also uses a big choke in a CLC setting.
There are also designs with supercaps, solid state regulation and still a choke because as the designer says the solid state regulation cannot do everything well.
AND with a true choke input you can do something that no other supply can do. Most of my supplies are choke input and some of them also use shunt regulation. I have had two devices that used sealed lead batteries.
It is up to every individual what they use.
Greetings Eduard
Hello,
But they did make a few with a higher current rating for me.
I have to check my account at the shop in Estonia to be sure which current ratings i ordered but if i remember well it was 2,5 or 2,75 A with the two windings in parallel .
My friend uses them for a stereo 20 watt Hiraga amp which draws around 1A for each channel. I think his amp was modified a little to bit to draw some extra current and now i understand why the chokes got hot. I never actually touched them in real life but i old him to change it back to ONE A per channel.
I run a test with the LL2771 with adjust current rating and did pull close to that rating in a choke input and temperature after hours was around 40 degrees. Of course the actual current will be about 25/30% lower so it will be ok. This choke was used for choke input supply.
I think 90% of the Lundahls i have, have their airgap adjusted to a lower current .
So choices become easier because the number of choices is limited.
So just get 4 LL2771 with a 1,5 or 1,75 A rating with windings in parallel.Make the correct connection ( see datasheet) using some solid core 1 or 1,5 mm diameter cable to connect the solder pins together and make a kind of wire wrap in the middle of each cable and depart from there to the rectifier and the first cap.
The solder " eyelets " on the choke have to be heated a lot during soldering. If you do it like this you only have to do it once. You can use super glue to attach the solid core a little to the choke board so pulling the cable will not harm the soldering to the eyelets.
The LL2771 did go up in price more than the other chokes. Why, because of its weight 4,9 kilogrammes so lots of copper and once it is packed it will be heavier than 5 kilogrammes so sending it will be in another price " category" . If you order 4 ( i got them in original wooden crates as used by Lundahl) it will be total weight above 20 and close to 25 kilogrammes.
But the shop in Estonia will offer free shipping above 500 €
About two months ago there were 3 LL2771 2A parallel on eBay in France. The ad is gone but could be they are not sold yet. I think the seller was in Bordeaux, maybe you can find him.
Greetings, Eduard
But they did make a few with a higher current rating for me.
I have to check my account at the shop in Estonia to be sure which current ratings i ordered but if i remember well it was 2,5 or 2,75 A with the two windings in parallel .
My friend uses them for a stereo 20 watt Hiraga amp which draws around 1A for each channel. I think his amp was modified a little to bit to draw some extra current and now i understand why the chokes got hot. I never actually touched them in real life but i old him to change it back to ONE A per channel.
I run a test with the LL2771 with adjust current rating and did pull close to that rating in a choke input and temperature after hours was around 40 degrees. Of course the actual current will be about 25/30% lower so it will be ok. This choke was used for choke input supply.
I think 90% of the Lundahls i have, have their airgap adjusted to a lower current .
So choices become easier because the number of choices is limited.
So just get 4 LL2771 with a 1,5 or 1,75 A rating with windings in parallel.Make the correct connection ( see datasheet) using some solid core 1 or 1,5 mm diameter cable to connect the solder pins together and make a kind of wire wrap in the middle of each cable and depart from there to the rectifier and the first cap.
The solder " eyelets " on the choke have to be heated a lot during soldering. If you do it like this you only have to do it once. You can use super glue to attach the solid core a little to the choke board so pulling the cable will not harm the soldering to the eyelets.
The LL2771 did go up in price more than the other chokes. Why, because of its weight 4,9 kilogrammes so lots of copper and once it is packed it will be heavier than 5 kilogrammes so sending it will be in another price " category" . If you order 4 ( i got them in original wooden crates as used by Lundahl) it will be total weight above 20 and close to 25 kilogrammes.
But the shop in Estonia will offer free shipping above 500 €
About two months ago there were 3 LL2771 2A parallel on eBay in France. The ad is gone but could be they are not sold yet. I think the seller was in Bordeaux, maybe you can find him.
Greetings, Eduard
I guess this applies to me
. Jean Hiraga's articles are translated into English, so that's not a problem for me and my wife speaks French fluently and my mother is a French language teacher so I have no problem with the translation from France . I agree that google translate is not good but chat GPT does a good job.
A 40-year-old design can be improved again, back then for example there were no semiconductors that exist today with which a superior regulator can be obtained. The best example is Hiraga's 20W with my improvements, only by replacing the zeners in the input stage with low-noise references I got an amplifier much better than the original. If Jean Hiraga could have done it then he certainly would have done it that way.
If everything is well calculated and dimensioned, I don't know how the transformer can go crazy. Normally, it can if it is overdone with electrolytes or too much current. Everything is possible in DIY.
I think it is still far from a first class regulator. That's my opinion and I have a reason that we can talk about by PM.
I agree that it is up to everyone to decide what to use, but also choke is not some holy grail that will lead us to the nirvana of good sound. I tried everything and only when I made a low-noise regulator for the tubes did I see how much time I wasted with the average sound and the classic style HV rectifier.
I would really like Jean Hiraga to hear my version of Le Monstre with regs and give his opinion afterwards, I'm sure he surprised you all