Still waiting for some parts and more involved in a phono stage so the DAC is taking a back seat.
Brian Lowe told me the values I selected for bleeders are fine:
3.3 V - calculated value 165R using two 330R 0.5 W in parallel
8 V - calculated value 400R using two 806R 0.5 W in parallel
Waiting for these resistors and rectifier diodes for the power supplies.
He figures the polymer caps would be fine on the input and output of the 3.3V reg. I must admit once I get all of this crammed in there I am not going to be too inspired to try another cap unless it sounds bad.
No polymers on the analog side. Figure I will go with the SILMICs for that side.
Soon as I get these resistors I will assemble a board and hear if it works.
Thank you for sharing this.
I'm wondering how you found those values.
Let's focus on the 3.3V half circuit, so for one 3.3V SPM. There's 20 mA for the whole 3.3V side, so 10mA out of one reg.
Mr Lowe says "Our measurements show, for a 100mA current step, a value that sinks about 20mA works well. Determining the optimum resistor is difficult because it depends not on the maximum average load current, but on the maximum change from average. However, a rule of thumb is a fixed load in the range of 10% to 20% of the average load."
So 20 % of 10mA is 2mA, according to this rule of thumb. That's the transient that has to be sinked.
R= U/I = 3.3/0.002 = 1650 Ohm !
But maybe it's not a problem to sink more, as the SPM is under light load (stands up to 250mA) ?
Beside that, have you read and performed the resistor and inductor removal suggested by Mr Lowe when I showed him some of the silkscreen ? I'll do them soon, but right now I'm still shocked by the reg's effect.
I'm wondering how you found those values.
Let's focus on the 3.3V half circuit, so for one 3.3V SPM. There's 20 mA for the whole 3.3V side, so 10mA out of one reg.
Mr Lowe says "Our measurements show, for a 100mA current step, a value that sinks about 20mA works well. Determining the optimum resistor is difficult because it depends not on the maximum average load current, but on the maximum change from average. However, a rule of thumb is a fixed load in the range of 10% to 20% of the average load."
So 20 % of 10mA is 2mA, according to this rule of thumb. That's the transient that has to be sinked.
R= U/I = 3.3/0.002 = 1650 Ohm !
But maybe it's not a problem to sink more, as the SPM is under light load (stands up to 250mA) ?
Beside that, have you read and performed the resistor and inductor removal suggested by Mr Lowe when I showed him some of the silkscreen ? I'll do them soon, but right now I'm still shocked by the reg's effect.
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Hello,
Please share your thoughts on the following link. It seems there are still some tricks to be done regarding the use of chokes.
Still didn't find the article about using standard EI transformers for digital gear to stop the device from polluting your mains or the mains polluting your digital equipment or both/
Sincere greetiungs, Edward
KISS 134: Noise Reduction with Lundahl’s Double-Coil Cut-C Core Chokes: a pictorial essay by Andre Jute
Please share your thoughts on the following link. It seems there are still some tricks to be done regarding the use of chokes.
Still didn't find the article about using standard EI transformers for digital gear to stop the device from polluting your mains or the mains polluting your digital equipment or both/
Sincere greetiungs, Edward
KISS 134: Noise Reduction with Lundahl’s Double-Coil Cut-C Core Chokes: a pictorial essay by Andre Jute
My DDDac build
This has been the most rewarding and enjoyable DIY project I have done so far. Many thanks to Doede for sharing this wonderful design.
Showing first hook-up utilizing stock output caps, PC USB power, and a Radio Shack wall wart to power the Dac. Already a good margin better than my trusty Marantz CD-63SE.
Now with Cinimag output xformers, and another veil is lifted from the picture, more soundstage and dare I say it, more musicality... (Note error on left output to cinimag primary which I caught before testing.)
Meanwhile, after much mulling over about power supplies, I decided to use Doede's design, but on my own PC board design to fit both 5v and 12v supplies. Board after etching/cleaning.
P/S board partially assembled.
And this is my build as it is now. One other mod was done - bias resistors swapped for Neohm 120 ohm .1% 5 ppm wirewound. (p/n UPW50B120RV). These looked very similar to the Rhopoint that some have raved about, cost about 3x less, and made a noticeable improvement.
This has been the most rewarding and enjoyable DIY project I have done so far. Many thanks to Doede for sharing this wonderful design.
Showing first hook-up utilizing stock output caps, PC USB power, and a Radio Shack wall wart to power the Dac. Already a good margin better than my trusty Marantz CD-63SE.
An externally hosted image should be here but it was not working when we last tested it.
Now with Cinimag output xformers, and another veil is lifted from the picture, more soundstage and dare I say it, more musicality... (Note error on left output to cinimag primary which I caught before testing.)
An externally hosted image should be here but it was not working when we last tested it.
Meanwhile, after much mulling over about power supplies, I decided to use Doede's design, but on my own PC board design to fit both 5v and 12v supplies. Board after etching/cleaning.
An externally hosted image should be here but it was not working when we last tested it.
P/S board partially assembled.
An externally hosted image should be here but it was not working when we last tested it.
And this is my build as it is now. One other mod was done - bias resistors swapped for Neohm 120 ohm .1% 5 ppm wirewound. (p/n UPW50B120RV). These looked very similar to the Rhopoint that some have raved about, cost about 3x less, and made a noticeable improvement.
An externally hosted image should be here but it was not working when we last tested it.
G600, those values should be per regulator. I was given them by someone from the Hifiwigwam forum who was helping me to order the shunt regulators. I didn't ask, but I can only assume the figures came from Doede.
Nice work Heathkit 🙂 nice, neat work and pretty cool to etch those boards. Did you use software to get the layout or do it by hand?
Nice work Heathkit 🙂 nice, neat work and pretty cool to etch those boards. Did you use software to get the layout or do it by hand?
OK. It deserves a confirmation from Doede, but I trust you more than me 🙂
Damn, I was proud of my explanation !
Indeed, this is some clean and calculated work. This thread is gathering some serious skills ! Heathkit, I wish you the same fun we have with your DDDAC.
Thanks! I used an old Paint Shop Pro program to draw it out, printed with laserjet to a special iron-on paper.
This is an interesting reading Edward.
There's an addition to it there KISS 135: Phasing in Lundahl’s Double-Coil Cut-C Core Chokes like the LL1638, by John Byrns
However, it's still a little above my understanding for now... Those chokes are a whole science by themselves !
Is there a problem to build the choke input and test it without any load (for sure the voltages will be higher) ?
There's an addition to it there KISS 135: Phasing in Lundahl’s Double-Coil Cut-C Core Chokes like the LL1638, by John Byrns
However, it's still a little above my understanding for now... Those chokes are a whole science by themselves !
Is there a problem to build the choke input and test it without any load (for sure the voltages will be higher) ?
Hello,
ALWAYS use a load because if you switch it on the tension can go up to high. It will go up the same like there is no choke so not 0.9 but 1.4. Just put a bleeder so the caps will also discharge. Maybe you will need a higher secundaryvtension not 12 volt but 14 volt. I will tell you some more later. Have to,work again. Greetings, edward
ALWAYS use a load because if you switch it on the tension can go up to high. It will go up the same like there is no choke so not 0.9 but 1.4. Just put a bleeder so the caps will also discharge. Maybe you will need a higher secundaryvtension not 12 volt but 14 volt. I will tell you some more later. Have to,work again. Greetings, edward
After some hours of careful work, this is where my PSU is :
Panasonic FC 2200µF/50V, 2 Schottky (thank you Stefan for the reference), and a 75 Ohm/50W resistor.
The 2 secondaries of ~15V get rectified at 22.4V after the two first caps, and 21.6V at the resistor. The two Lundahls are connected serially as showed in their data sheet.
Now I need to order my tailored power transformer, with lower secondaries. The voltage is too high for connecting the Motherboard (no problem for the Belleson as they handle up to 35V, but there are still 3* stock TO-220 regulators on the motherboard).
Best regards and thanks again for your help.
PS : the DDDAC is still playing untouched after the Belleson mod a few days ago, I just can't stop listening !
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Panasonic FC 2200µF/50V, 2 Schottky (thank you Stefan for the reference), and a 75 Ohm/50W resistor.
The 2 secondaries of ~15V get rectified at 22.4V after the two first caps, and 21.6V at the resistor. The two Lundahls are connected serially as showed in their data sheet.
Now I need to order my tailored power transformer, with lower secondaries. The voltage is too high for connecting the Motherboard (no problem for the Belleson as they handle up to 35V, but there are still 3* stock TO-220 regulators on the motherboard).
Best regards and thanks again for your help.
PS : the DDDAC is still playing untouched after the Belleson mod a few days ago, I just can't stop listening !
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Hello,
You did put the cap directly after the rectifier so it isnt a choke input but a cap input that is why the tension is so '' high'' If you put one choke after the rectifier you will get about 13 volts. THEN you can listen to it.
Only 220mf not 2200?
Heat up your soldering device and make it choke input and listen a few minutes and then you will know.
Take good of the transformer you use. Some are better then others.
Sincere greetings, Edward
You did put the cap directly after the rectifier so it isnt a choke input but a cap input that is why the tension is so '' high'' If you put one choke after the rectifier you will get about 13 volts. THEN you can listen to it.
Only 220mf not 2200?
Heat up your soldering device and make it choke input and listen a few minutes and then you will know.
Take good of the transformer you use. Some are better then others.
Sincere greetings, Edward
No, 2200µF, my bad.
Yes, there are 2 caps before the first choke, I'll change that !
Indeed transformers aren't equal, and mine is bad. Small and hums when connected to Doede's modified PSU.
I'm dreaming of a 200VA C-core audio grade built, a local firm can assemble one for the price of 2 shunt regs 🙂
Best regards.
Yes, there are 2 caps before the first choke, I'll change that !
Indeed transformers aren't equal, and mine is bad. Small and hums when connected to Doede's modified PSU.
I'm dreaming of a 200VA C-core audio grade built, a local firm can assemble one for the price of 2 shunt regs 🙂
Best regards.
Hello,
With choke input the transformer has a much easier life and can be made smaller. Allen Wright did say the choke should be bigger than the transformer.
They that the transformers used by heathkit are nice. On one side you have the primary and on the other side there is the secundary. Some this is better than a static shield between the 2 of them.
I am not sure you need an audio grade transformer for the dac. I mean the tension you need is not a special one. Maybe you can find a potted one in a surplus store. I think static screen could be nice.
A pity you are in France i could lend you a few to try lol.
Sincere greetings, Edward
With choke input the transformer has a much easier life and can be made smaller. Allen Wright did say the choke should be bigger than the transformer.
They that the transformers used by heathkit are nice. On one side you have the primary and on the other side there is the secundary. Some this is better than a static shield between the 2 of them.
I am not sure you need an audio grade transformer for the dac. I mean the tension you need is not a special one. Maybe you can find a potted one in a surplus store. I think static screen could be nice.
A pity you are in France i could lend you a few to try lol.
Sincere greetings, Edward
Hello,
Hello to all the Guido tent shunt users. Next week i need to order at a company where they also sell the silmic. I will go for the choke power supply like supersurfer did but probably go for a choke input.
Will start with one mainboard( obvious) and one dac board. Will need 22 * 47mf for the dac and 1*470mf plus 3*47mf for the mainboard. If i wanna go Oscon plus silmic which quantity do i have to buy if i will use one dac board with 4 shunts? Numbers needed for the big power supply i can figure out myself.
Many thanks in advance, Edward
Hello to all the Guido tent shunt users. Next week i need to order at a company where they also sell the silmic. I will go for the choke power supply like supersurfer did but probably go for a choke input.
Will start with one mainboard( obvious) and one dac board. Will need 22 * 47mf for the dac and 1*470mf plus 3*47mf for the mainboard. If i wanna go Oscon plus silmic which quantity do i have to buy if i will use one dac board with 4 shunts? Numbers needed for the big power supply i can figure out myself.
Many thanks in advance, Edward
Seems pretty hard to figure out, because everyone is using more or less caps, depending on preference, space, cap size, etc...
Hello,
I just did take a look at the dac board from supersurfer. If you read his post and look at the photos you can see 2 small oscon, 4*100mf silmic and6*47mf silmic on the dac board and some oscon on the motherboard. We will wait for him to confirm.
Sincere greetings, edward.
p.s Amienois did you gert your choke input working?
I just did take a look at the dac board from supersurfer. If you read his post and look at the photos you can see 2 small oscon, 4*100mf silmic and6*47mf silmic on the dac board and some oscon on the motherboard. We will wait for him to confirm.
Sincere greetings, edward.
p.s Amienois did you gert your choke input working?
I'm not at home till monday, it"s vacancy time for students right now.
I'm sure it will work very soon, but would it be a good idea to try capacitor input with chokes, like Stefans, and after to give choke input a try ? There are different flavours out there, it may be a good chance for me to learn about this...
I have received some Silmics and new Oscons pointed by James, I'll next tweak the deck and do the changes advised by Brian Lowe.
Best regards, don't forget to listen and enjoy the DAC between soldering sessions !
I'm sure it will work very soon, but would it be a good idea to try capacitor input with chokes, like Stefans, and after to give choke input a try ? There are different flavours out there, it may be a good chance for me to learn about this...
I have received some Silmics and new Oscons pointed by James, I'll next tweak the deck and do the changes advised by Brian Lowe.
Best regards, don't forget to listen and enjoy the DAC between soldering sessions !
Hello,
It would be nice if you have a transformer with a few secindary tensions so you can use a higher tension when you switch to choke input.
http://www.produktinfo.conrad.com/datenblaetter/500000-524999/514365-da-01-en-Trafo_7_5_18_5A.pdf
Something like this it will be 33 euro. They say one with primary and secundary winding next to each other could be better. You can also buy one with less current rating and then a bigger one when you know what tension you need.
If you compare choke input with cap input using the same AC tension your regulator will also function differently. One dc tension will be better than the other. If it is to high the regulator gets more heat. If it is to low it will not regulate very well.
Right now i dont have the DAC but i will get one later for sure. I must buy some other things first.( ampli monotriode WE vt25)
Sincere greetings, Edward
It would be nice if you have a transformer with a few secindary tensions so you can use a higher tension when you switch to choke input.
http://www.produktinfo.conrad.com/datenblaetter/500000-524999/514365-da-01-en-Trafo_7_5_18_5A.pdf
Something like this it will be 33 euro. They say one with primary and secundary winding next to each other could be better. You can also buy one with less current rating and then a bigger one when you know what tension you need.
If you compare choke input with cap input using the same AC tension your regulator will also function differently. One dc tension will be better than the other. If it is to high the regulator gets more heat. If it is to low it will not regulate very well.
Right now i dont have the DAC but i will get one later for sure. I must buy some other things first.( ampli monotriode WE vt25)
Sincere greetings, Edward
In fact the trafo I'm using has two 9V secondaries too, you can see them untied on some of my photos.
I'll try capacitor input with chokes that way, I may have a little less than 12V then.
I know you don't have this fine piece of a DAC right now, it was just a general disclaimer from me 😀
I'll try capacitor input with chokes that way, I may have a little less than 12V then.
I know you don't have this fine piece of a DAC right now, it was just a general disclaimer from me 😀
Hello,
I think with 2*9 volts in series the tension will be to high. Also depends how much current your dac will use. The second choke you will loose 1.8 volts if your circuits plus bleeder take 1 A total. The input choke used after the rectifier will loose more because it is AC. Probably you will need 15 or 16 volts. If you get a transformer with 220-230-240 on primary side you can change secondary tension a little bit too.
I am very curious which one you will like.
Sincere greetings, Edward
I think with 2*9 volts in series the tension will be to high. Also depends how much current your dac will use. The second choke you will loose 1.8 volts if your circuits plus bleeder take 1 A total. The input choke used after the rectifier will loose more because it is AC. Probably you will need 15 or 16 volts. If you get a transformer with 220-230-240 on primary side you can change secondary tension a little bit too.
I am very curious which one you will like.
Sincere greetings, Edward