If you want to go the easy way, why not use the existing examples?
1) Use the schematic I shared here: post-7533447
2 x Lundhal 1694 is used in this example. About 90€ each. You can adjust the output voltage by choosing the correct transformer.
2) Or using Hammond Choke like suggested by Doede. Less expensive if you have already a DDDAC PSU and without any risk because voltage regulation is also covered:
Link to DDDAC BLOG PSU Post
1) Use the schematic I shared here: post-7533447
2 x Lundhal 1694 is used in this example. About 90€ each. You can adjust the output voltage by choosing the correct transformer.
2) Or using Hammond Choke like suggested by Doede. Less expensive if you have already a DDDAC PSU and without any risk because voltage regulation is also covered:
Link to DDDAC BLOG PSU Post
Hello,
I don't have a car nor a driving license just a normal, more than average quality bicycle not even an electric one so i can spend a one day salary on a choke that will last a lifetime.
I am using the DDDAC with the Sowter output transformers designed by Doede. I started with the ll2733 because that was the biggest high current choke Lundahl made at that time and when they released the LL2771 which is 70 % more expensive, required another to configure the secundairy connections on the transformer differently and to do some small metalwork as well because the ll2771 is surely bigger.
It will always be about spending money. Probably if you tell your neighbour about the power supply cost of your dddac or any other part of it probably he will say you are nuts.
Greetings Eduard
I don't have a car nor a driving license just a normal, more than average quality bicycle not even an electric one so i can spend a one day salary on a choke that will last a lifetime.
I am using the DDDAC with the Sowter output transformers designed by Doede. I started with the ll2733 because that was the biggest high current choke Lundahl made at that time and when they released the LL2771 which is 70 % more expensive, required another to configure the secundairy connections on the transformer differently and to do some small metalwork as well because the ll2771 is surely bigger.
It will always be about spending money. Probably if you tell your neighbour about the power supply cost of your dddac or any other part of it probably he will say you are nuts.
Greetings Eduard
guys, there are many ways leading to success, they might all be a bit different and cost will differ largely. sonic benefit also differs, but with chokes it is always an improvement.
my suggestion is always to start simple and without extreme cost. Listen, get a feel what it does and if you want you can move on from that point.
if Michl already mentioned, why not start with existing examples?
my suggestion is always to start simple and without extreme cost. Listen, get a feel what it does and if you want you can move on from that point.
if Michl already mentioned, why not start with existing examples?
Hello,
The circuit that Michl proposed is easy.
It raised some questions but i dont know the answers.
Why not use 4 diodes?
Now there are two " secondary parts" which theoretically can never be identical.
Why not use sbyv28 at 50 dollar cents each.
I would go for a bigger ( ll2733)input choke with adjusted airgap followed by ll1694 or even a simple RC network. I expect better results with more mH for the input choke which also reduces the minimum current needed to waste by means of the bleeder.
Of course you could also invest in the new boards to be released next year.
Greetings Eduard
The circuit that Michl proposed is easy.
It raised some questions but i dont know the answers.
Why not use 4 diodes?
Now there are two " secondary parts" which theoretically can never be identical.
Why not use sbyv28 at 50 dollar cents each.
I would go for a bigger ( ll2733)input choke with adjusted airgap followed by ll1694 or even a simple RC network. I expect better results with more mH for the input choke which also reduces the minimum current needed to waste by means of the bleeder.
Of course you could also invest in the new boards to be released next year.
Greetings Eduard
Hi all, my 2 cents contribution...
I personally like the 'poor clever man' approach, learning and experimenting looking for the best improvements/cost ratio, it is very satisfying for me.
I applied the CLC tweak suggested by Doede using the Hammond 159ZC choke + 22.000uF as second capacitor and the sonic result has been stunning for me considering I spent about 45€... very very satisfying experience (see post 9353 from Doede).
Sure I expect better results from better or more expensive components/solutions, but good cheap results have a special taste for me.
My dream for the future is to have 26 tapped tranformers to get balanced output from the DDDAC and properly feed my F6 Pass ampli, avoiding 1.2volt max output, capacitor coupling and software control volume... in the mean time I'm looking for cheaper alternative learning a lot day by day.
Thanks to all for this inspirational forum !!
Max
I personally like the 'poor clever man' approach, learning and experimenting looking for the best improvements/cost ratio, it is very satisfying for me.
I applied the CLC tweak suggested by Doede using the Hammond 159ZC choke + 22.000uF as second capacitor and the sonic result has been stunning for me considering I spent about 45€... very very satisfying experience (see post 9353 from Doede).
Sure I expect better results from better or more expensive components/solutions, but good cheap results have a special taste for me.
My dream for the future is to have 26 tapped tranformers to get balanced output from the DDDAC and properly feed my F6 Pass ampli, avoiding 1.2volt max output, capacitor coupling and software control volume... in the mean time I'm looking for cheaper alternative learning a lot day by day.
Thanks to all for this inspirational forum !!
Max
If the last % is your goal it gonna be complex, if you want a reasonable update ...cost speaking ... the solution Doede discribe a few post before #9,353
is as Max said
In my ears ...62 years old
it is a cheap but very welcome upgrade, I love my analogue sound and this is the cherry on my cake, just the thouch I was looking for... simple but with great result...
I think I can seal my enclosure now
is as Max said
In my ears ...62 years old
it is a cheap but very welcome upgrade, I love my analogue sound and this is the cherry on my cake, just the thouch I was looking for... simple but with great result...I think I can seal my enclosure now
You can also use 4 diodes with a different transformer, no problem. If you exchange the first section (marked red) you will not change the main principle of the circuit. The choke section which does the main work will be the same. The diode in the schematic is just the standard one which is taken by PSU Designer by default. I also use a fast recovery diode in my setup. It is less than one 1€, like you said,
Hello,
We , the old guys, remember when the youngs guys said.
Chokes are from the past when caps had low capacity so we needed the iron to filter things out. Now with " higher density" caps chokes are just a waste.
And look what we can achieve with present day regulators . Chokes are like steam engines.
But then there were some folks popping up saying that these chokes are kind of wonderful. Describing them as electronic flywheels which impressed me because i have seen the influence of a flywheel on an eccentric press.
Some people say regulators could produce some impressive specs but they do with adding things that our ears don't like. A bit like the first cd player.
If you read the specs on some old Parmeko transformers you will see that with choke input they could deliver a higher output current than with a cap input.
With the Dddac and a few boards we need some serious caps to obtain a low ripple. Big caps means big charging currents being present in the transformer, diodes, the first cap and the wires in between them. Using a decent mH choke will " flatten " the current flow to the average current taken by the circuit.
There have been a few choke input power supply users here for the DDDAC but it requires some investment.
There have been people removing the 7810 regulators on the tiny boards but i had to take the boards apart to do that and you must be sure not to overheat the fets.
NOW i will just replace my present 4 board Dddac by a two or four new boards Dddac once available.
Life is easy with a non profit guy like Doede around not a new update every 3 months.
Greetings Eduard
We , the old guys, remember when the youngs guys said.
Chokes are from the past when caps had low capacity so we needed the iron to filter things out. Now with " higher density" caps chokes are just a waste.
And look what we can achieve with present day regulators . Chokes are like steam engines.
But then there were some folks popping up saying that these chokes are kind of wonderful. Describing them as electronic flywheels which impressed me because i have seen the influence of a flywheel on an eccentric press.
Some people say regulators could produce some impressive specs but they do with adding things that our ears don't like. A bit like the first cd player.
If you read the specs on some old Parmeko transformers you will see that with choke input they could deliver a higher output current than with a cap input.
With the Dddac and a few boards we need some serious caps to obtain a low ripple. Big caps means big charging currents being present in the transformer, diodes, the first cap and the wires in between them. Using a decent mH choke will " flatten " the current flow to the average current taken by the circuit.
There have been a few choke input power supply users here for the DDDAC but it requires some investment.
There have been people removing the 7810 regulators on the tiny boards but i had to take the boards apart to do that and you must be sure not to overheat the fets.
NOW i will just replace my present 4 board Dddac by a two or four new boards Dddac once available.
Life is easy with a non profit guy like Doede around not a new update every 3 months.
Greetings Eduard
There are still capacitors used in the choke supply. So comparsion would more be RC ("standard" supply) vs LC (choke supply). LC has better filter characteristics (second order filter, additional 20dB against RC). So it helps to keep away the garbage coming from the mains and there is lower ripple at the output (no regulator needed in case of LCLC). And like eduard mentioned, there is a more constant current flow which helps the transformer and diodes to work better. So in my point of view, the choke supply is a low noise / low ripple power supply with low impendance which can deliver fast a high amount of energy to your device. But they require a lot of metal, they are big and expensive. Compromise is to upgrade the DDDAC PSU with one choke like Doede demonstrated. Then you have a CLC filter which has better filter characteristics than standard DDDAC PSU (CRC). This solution is less expensive with less space required. There is a voltage regulation needed then, but this is exactly what the DDDAC PSU does in this case and why a single choke works in this setup.
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The difference between RC and LC is obvious (1st order vs. 2nd order filter). The difference between choke input and capacitor input is not so obvious to me, so that's why I asked.
The explanation by @eduard does not click with my brain. The transformer works with AC, while eduard seems to argue the current would be constant in the transformer.
Hello,
The choke will try everything to keep the current through it as constant as possible.
If the choke will keep things steady so will the transformer, caps and rectifier have an advantage. With choke input the transformer wont heat up as much because there are no more current bursts.
Somewhere on this site i published a copy of a French magazine that shows the difference in current and the shape of the ripple between cap and choke input. Making the input cap bigger will only make the problem bigger. Maybe search function can help you find it.
Greetings Eduard
The choke will try everything to keep the current through it as constant as possible.
If the choke will keep things steady so will the transformer, caps and rectifier have an advantage. With choke input the transformer wont heat up as much because there are no more current bursts.
Somewhere on this site i published a copy of a French magazine that shows the difference in current and the shape of the ripple between cap and choke input. Making the input cap bigger will only make the problem bigger. Maybe search function can help you find it.
Greetings Eduard
Maybe i posted this one before but still could be interesting to members.
Article from a famous french engineer where you can see differences between choke and capacitor input when used to supply a 180 ma current.
On the left top choke input bottom cap input. On the right the current demand with choke input around 180 mA as requested by the load. With cap input switching between 180 and 425 mA. These peaks also occur in the transformer, diodes and the wires taking care of the connections. And this is only 180 mA most heater current are much higher.
So one more reason to use a decent choke input
Article from a famous french engineer where you can see differences between choke and capacitor input when used to supply a 180 ma current.
On the left top choke input bottom cap input. On the right the current demand with choke input around 180 mA as requested by the load. With cap input switching between 180 and 425 mA. These peaks also occur in the transformer, diodes and the wires taking care of the connections. And this is only 180 mA most heater current are much higher.
So one more reason to use a decent choke input
Sure, I totally understand that with a choke input the choke will try to keep a constant current passing through it (with the voltage pulsating against the AC of the transformer output).
Similarly, with a capacitor input one can say that capacitor will try to keep a constant voltage across it (with the corresponding current pulses to keep the cap charged).
So, why is one better than the other?
Similarly, with a capacitor input one can say that capacitor will try to keep a constant voltage across it (with the corresponding current pulses to keep the cap charged).
So, why is one better than the other?
Today I tested my PSU with a little choke for fun and giggle. This choke (I did not add a resistor in series)
After I inserted the choke, my transformer went mad and a lot of hum was audible. The voltage, measuring after the rectifier diode is 17V DC without the choke. With the choke it dropped to 13.5V DC. But why? Its resistance is only 0.85 Ohm.
Beside the loud hum from the transformer, my other device in the room stopped with an error, I needed to restart it.
Can a little choke cause such a big mess to the main voltage??
After I inserted the choke, my transformer went mad and a lot of hum was audible. The voltage, measuring after the rectifier diode is 17V DC without the choke. With the choke it dropped to 13.5V DC. But why? Its resistance is only 0.85 Ohm.
Beside the loud hum from the transformer, my other device in the room stopped with an error, I needed to restart it.
Can a little choke cause such a big mess to the main voltage??
Hello,
Take a look at the scope image on the left.
Both " traces" are measured at the first cap. The one above is with a Two Henry choke input. The one underneath without the choke.
With choke a nice wave with 0,6 volt ripple.
Without choke a terrible sawtooth 5 volts.
Image right with choke nice steady current draw similar to the one presented by the load.
Without choke current bouncing between 180 and 425 mA.
Transformer, diodes and caps will not like that and this happening all of the time.
Greetings Eduard
Take a look at the scope image on the left.
Both " traces" are measured at the first cap. The one above is with a Two Henry choke input. The one underneath without the choke.
With choke a nice wave with 0,6 volt ripple.
Without choke a terrible sawtooth 5 volts.
Image right with choke nice steady current draw similar to the one presented by the load.
Without choke current bouncing between 180 and 425 mA.
Transformer, diodes and caps will not like that and this happening all of the time.
Greetings Eduard
Hello,
Of course you should know a little bit what you are doing!!
Some people use so called common mode chokes which are meant for ac filtering.
All the info is in this thread. A choke that can be used for choke must have enough mH , must have an airgap and wIll be more than 5 $
When changing from cap to choke input you will need a transformer with higher ac output. If you can use the same transformer you surely did not make a choke input.
Greetings Eduard