Hey Faux French, I'm just practicing at the moment, I know they are small but it's just to check and famalirise myself around these circuits.
I get around 37v over each rail, but I thought I'm supposed to use both rails? This creates V+ and V- with common ground correct?
If I use one rail for the amplifier I have a spare rail? Surely I should using them both.
If any of that makes sense. You'll see in my diagram above the voltages I get.
I get around 37v over each rail, but I thought I'm supposed to use both rails? This creates V+ and V- with common ground correct?
If I use one rail for the amplifier I have a spare rail? Surely I should using them both.
If any of that makes sense. You'll see in my diagram above the voltages I get.
Ok it's starting to make sense, it's just im following diagrams and what other members have told me to do.
I assumed that combing the bridges, creating a dual rail circuit with a common would give 37volts.
Yes Fabrice it does require basic skills, those I am trying to learn now man! I'm doing ok so far. Remember this is my first time building from scratch something like this.
So basically if I used another transformer with voltages of say 2X18vac I would get something like 40v instead? But then by using resistors and loading it I can get it down to say 24v?
It's making sense now. Bare with me I learn by doing at the moment!
I assumed that combing the bridges, creating a dual rail circuit with a common would give 37volts.
Yes Fabrice it does require basic skills, those I am trying to learn now man! I'm doing ok so far. Remember this is my first time building from scratch something like this.
So basically if I used another transformer with voltages of say 2X18vac I would get something like 40v instead? But then by using resistors and loading it I can get it down to say 24v?
It's making sense now. Bare with me I learn by doing at the moment!
I guess what you want is plus and minus 28 volts (56 total) as per the circuit you posted?
Heed what fabrice63 says. You do not have a load on the supply. So the voltage will rise to the 'smoothed' value due to the capacitors. Typically 1.4 times the AC value. So as was said before a 24 volt ac transformer will give you about 35 volts dc smoothed i.e with a capacitor. I also note that the transformer is a 230 ac volt input, so on normal British mains 240/245 volts will give you a couple more DC volts too, so 37 volts dc is what you have to expect. All is good so far.
What is missing is the load or 'work' the supply has to do. Until you have that no actual current flows through the circuit and the voltage cannot 'drop'.
You have to know how much current the amplifier will use before you can calculate the resistance of the resistors and choke in the power supply to bring it down to the 2 x 28 (56) volts.
You have to use both rails (3 connections) by the way.
Heed what fabrice63 says. You do not have a load on the supply. So the voltage will rise to the 'smoothed' value due to the capacitors. Typically 1.4 times the AC value. So as was said before a 24 volt ac transformer will give you about 35 volts dc smoothed i.e with a capacitor. I also note that the transformer is a 230 ac volt input, so on normal British mains 240/245 volts will give you a couple more DC volts too, so 37 volts dc is what you have to expect. All is good so far.
What is missing is the load or 'work' the supply has to do. Until you have that no actual current flows through the circuit and the voltage cannot 'drop'.
You have to know how much current the amplifier will use before you can calculate the resistance of the resistors and choke in the power supply to bring it down to the 2 x 28 (56) volts.
You have to use both rails (3 connections) by the way.
I believe we all agree that the ground line (0V rail), the negative rail and the positive rail are all needed for the Jean Hiraga amplifer. And, you know now how to connect the wires to have the a ground line, a negative rail and the positive rail.
Then, we can move on to the next question: do you have the right rail voltages?
Unloaded, you have +37V and -37V from the 2x24Vac transformer.
I do not know the Jean Hiraga amplifier but I found a schematic on the Internet (Pinterest) showing that the supply voltages should be +/-35V. With loading, your present +/-37V will drop to around +/-34V. Fine. But I see statements here that the supply voltage should be +/-28V!
Is +/-35V or +/-28V the right supply voltage?
Then, we can move on to the next question: do you have the right rail voltages?
Unloaded, you have +37V and -37V from the 2x24Vac transformer.
I do not know the Jean Hiraga amplifier but I found a schematic on the Internet (Pinterest) showing that the supply voltages should be +/-35V. With loading, your present +/-37V will drop to around +/-34V. Fine. But I see statements here that the supply voltage should be +/-28V!
Is +/-35V or +/-28V the right supply voltage?
Fair enough, but then we have to find a way to reduce the voltages to 28V.
Three ways are known to me:
1) A voltage regulator circuit,
2) a primary pre-transformer (step-down),
3) a new transformer with 2x18Vac secondary voltages.
May I ask, why do you have a 2x24Vac transformer if you need 2x28Vdc? You must have got the indication of value from somewhere?
Three ways are known to me:
1) A voltage regulator circuit,
2) a primary pre-transformer (step-down),
3) a new transformer with 2x18Vac secondary voltages.
May I ask, why do you have a 2x24Vac transformer if you need 2x28Vdc? You must have got the indication of value from somewhere?
I wanted to use an r core transformer and I was having a hard time sourcing them, to make would have been expensive.
I picked a pair of these r core transformers for cheap, at a bargain price so couldn't say no.
Hence why I'm trying to use them.
I have been getting help from some of the members with circuit design, resistor values etc. So now I'm just trying to put it all together and make sense of it.
I picked a pair of these r core transformers for cheap, at a bargain price so couldn't say no.
Hence why I'm trying to use them.
I have been getting help from some of the members with circuit design, resistor values etc. So now I'm just trying to put it all together and make sense of it.
Fine, you have a powerful R-core transformer bought at an attractive price.
A regulator circuit will have important power losses if of the linear type, or important switching noise if of the switching type.
Then, I will propose a primary step-down transformer. The function of such a primary step-down transformer is to reduce the input voltage to your R-core transformer such that the output voltages of the R-core transformer becomes what you need for 2x28Vdc.
Sounds OK with you, or you have other preferences?
Would you happen to have other transformers lying idle at home?
A regulator circuit will have important power losses if of the linear type, or important switching noise if of the switching type.
Then, I will propose a primary step-down transformer. The function of such a primary step-down transformer is to reduce the input voltage to your R-core transformer such that the output voltages of the R-core transformer becomes what you need for 2x28Vdc.
Sounds OK with you, or you have other preferences?
Would you happen to have other transformers lying idle at home?
Then, I will propose a primary step-down transformer. The function of such a primary step-down transformer is to reduce the input voltage to your R-core transformer such that the output voltages of the R-core transformer becomes what you need for 2x28Vdc.
probably not needed, i think when the circuit is built with the chokes, the right value resistors and under load i should hopefully get 28-30vdc
Sounds OK with you, or you have other preferences?
My preference would be to see what voltages i get first within the rails
Would you happen to have other transformers lying idle at home?[/QUOTE]
I have two toroidal transformers 160va 2x12ac for another future project!
probably not needed, i think when the circuit is built with the chokes, the right value resistors and under load i should hopefully get 28-30vdc
Sounds OK with you, or you have other preferences?
My preference would be to see what voltages i get first within the rails
Would you happen to have other transformers lying idle at home?[/QUOTE]
I have two toroidal transformers 160va 2x12ac for another future project!
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