Hello Chanh,
The shop in France where we did talk about has two chokes with dual coils which can be used in common mode connection. One is rated for 2.5A and the other one is rated for 5A.
The r-core 300va 2*15 volts will take some more weeks to arrive. French people dont like to work in the summer.
Usually i will check a few times a week but youi can also ask them to send you an email once they are in stock.
The two lundahl chokes ll1694 and ll2733 have a to low current rating to be used in common mode connection in your situation.
Maybe you can get the 5A model in France when the transformer will be in stock again?
When used in common mode for choke input you can add up the two coils when you want to calculate the critical induction. So it will function the same like one 40mH on the plus side but it will filter in a better way they say.
The only thing you can do is try and tell us which one you like. I will get the 2 lundahls and an output transformer with gain and just 4 boards with shunts.
Sincere greetings, edward.
p.s if you need help i can help you order in france
The shop in France where we did talk about has two chokes with dual coils which can be used in common mode connection. One is rated for 2.5A and the other one is rated for 5A.
The r-core 300va 2*15 volts will take some more weeks to arrive. French people dont like to work in the summer.
Usually i will check a few times a week but youi can also ask them to send you an email once they are in stock.
The two lundahl chokes ll1694 and ll2733 have a to low current rating to be used in common mode connection in your situation.
Maybe you can get the 5A model in France when the transformer will be in stock again?
When used in common mode for choke input you can add up the two coils when you want to calculate the critical induction. So it will function the same like one 40mH on the plus side but it will filter in a better way they say.
The only thing you can do is try and tell us which one you like. I will get the 2 lundahls and an output transformer with gain and just 4 boards with shunts.
Sincere greetings, edward.
p.s if you need help i can help you order in france
Here is some of my handy work inspired by the result you guys were getting.
My toroidal transformer (rated at 2x12V) was giving me 2x12.6v so I did some surgery to it and took off 4 turns on both secondary windings to get down to 2x12v. When powering the DDDAC with 4 board and standard regulators that resulted in 12 Vdc under load, using 2x parallel 100Ohm/10watt bleeders. The bleeders are 66C warm measured at the top (currenlty 27C ambient indoors) and only heet up the caps next to it 2C above the rest, so no problem there.
First impression sounds wise, I'm very impressed, this is a great addition, I'm glad your enthousiasme made me give it a try in the end. The sound is much more analogue/natural/easy/lucid sounding, across the frequency range detail and tone seem more balanced. The bass has more definition and I have no problem in it lacking power in anyway (like Chanh was experiencing). Still early days and the caps need more burn in time obviously.
Thanks guys,
My toroidal transformer (rated at 2x12V) was giving me 2x12.6v so I did some surgery to it and took off 4 turns on both secondary windings to get down to 2x12v. When powering the DDDAC with 4 board and standard regulators that resulted in 12 Vdc under load, using 2x parallel 100Ohm/10watt bleeders. The bleeders are 66C warm measured at the top (currenlty 27C ambient indoors) and only heet up the caps next to it 2C above the rest, so no problem there.
First impression sounds wise, I'm very impressed, this is a great addition, I'm glad your enthousiasme made me give it a try in the end. The sound is much more analogue/natural/easy/lucid sounding, across the frequency range detail and tone seem more balanced. The bass has more definition and I have no problem in it lacking power in anyway (like Chanh was experiencing). Still early days and the caps need more burn in time obviously.
Thanks guys,
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Hello Stijn,
Listen to it some more and then try to change it into choke input using a 15 volt transformer.
Maybe you will need to '' bleed '' some more current.
Because you are using the lundahls you can try the choke input as a standard choke or as a common mode choke.
Sincere greetings, edward.
p.s the 15 volts 300va R core will probably arrive mid august. I did buy the last one.
Listen to it some more and then try to change it into choke input using a 15 volt transformer.
Maybe you will need to '' bleed '' some more current.
Because you are using the lundahls you can try the choke input as a standard choke or as a common mode choke.
Sincere greetings, edward.
p.s the 15 volts 300va R core will probably arrive mid august. I did buy the last one.
Today I have finally received a response from Guido stating that my 47 Shunts are currently populating. They should be ready for a release and ship to Australia sometime early next week! Hooooray....!!! 
I was particularly concern with the post payment silence at his end. As it turned out, the man is busy perfecting my order. Many thanks Guido.
With regards to Non-European order at Audio Creative Shop Audio Creative is de site voor zelfbouw audio. I have placed my new order with them, the addition 3 more Dac boards and another new main-board with SPDIF. Note the prices listed at their website are including VAT for the local. Non-European order will not be liable to local European tax at the checkout. As it turned out, the prices for these DDDAC were misleadingly listing for over continent order. When Doede ran the logistic himself, we paid 79 Euro for a DAC board kit, with Marco's proper business setup, he charges 81 Euro but with prompt response and fast order execution. For a couple more Euro, it is all well worth it and much more professionally servicing. Here not to say Doede was any less professional, he is but there can only be those many we could put in his plate. Therefore his decision to walk away from the business logistic seems logical. One thing I found to be pleasant was the mainboard with SPDIF includes Tentclock at 130 Euro ext VAT. A 19 Euro less than what I paid when the new mainboard was released, 120 Euro for mainboard, and 29 Euro for the Tentclock.
It will definitely be exciting time for me with all these mod. Hopefully the mod I done can come close to the SQ of a turntable/vinyl. Will keep you all posted when the time comes.
Best,
Chanh
I was particularly concern with the post payment silence at his end. As it turned out, the man is busy perfecting my order. Many thanks Guido.
With regards to Non-European order at Audio Creative Shop Audio Creative is de site voor zelfbouw audio. I have placed my new order with them, the addition 3 more Dac boards and another new main-board with SPDIF. Note the prices listed at their website are including VAT for the local. Non-European order will not be liable to local European tax at the checkout. As it turned out, the prices for these DDDAC were misleadingly listing for over continent order. When Doede ran the logistic himself, we paid 79 Euro for a DAC board kit, with Marco's proper business setup, he charges 81 Euro but with prompt response and fast order execution. For a couple more Euro, it is all well worth it and much more professionally servicing. Here not to say Doede was any less professional, he is but there can only be those many we could put in his plate. Therefore his decision to walk away from the business logistic seems logical. One thing I found to be pleasant was the mainboard with SPDIF includes Tentclock at 130 Euro ext VAT. A 19 Euro less than what I paid when the new mainboard was released, 120 Euro for mainboard, and 29 Euro for the Tentclock.
It will definitely be exciting time for me with all these mod. Hopefully the mod I done can come close to the SQ of a turntable/vinyl. Will keep you all posted when the time comes.
Best,
Chanh
Hello Chanh and the others,
The 300va R core did arrive at my door some days ago. Yesterday i did order the ll1694 and ll2733 chokes.
Want to use the ll2733 as a common mode choke input which will be a 400mH rated at 1.7A. The second filter stage will be the ll1694 which will be 160mH at 1.5A.
Because the current running through the chokes are rather big i did decide to cast the transformer and the chokes in a polyurethane compound.
The best way to shield is to use a shield with a round or oval shape. I can weld an oblong shape at work and put an oval shaped shield inside from mu metal which can be glued but not welded. Because welding will make it loose it shielding properties.
Can add a copper foil to stop other interferences as well.
It is said that especially the wires from the transformer to the diodes, first choke and caps should be short. My chassis is home made at my company so i can make something to mount the first choke on top of the transformer if i can minimize interference by magnetic fields.
I remember long time ago i did move the power transformer from underneath a turntable platter to a position just about 10 inches away. There wasnt a hum in the first place but moving it did improve low level information. So i can guess buying a gaussmeter could be a good a good investment.
My transformer has two identical secundary windings. I can put them in paralellel and using 4 diodes or use 2 diodes and put them in series and use the cetre tap as ground. Which solution will be better?
Sincere greetings, Edward
The 300va R core did arrive at my door some days ago. Yesterday i did order the ll1694 and ll2733 chokes.
Want to use the ll2733 as a common mode choke input which will be a 400mH rated at 1.7A. The second filter stage will be the ll1694 which will be 160mH at 1.5A.
Because the current running through the chokes are rather big i did decide to cast the transformer and the chokes in a polyurethane compound.
The best way to shield is to use a shield with a round or oval shape. I can weld an oblong shape at work and put an oval shaped shield inside from mu metal which can be glued but not welded. Because welding will make it loose it shielding properties.
Can add a copper foil to stop other interferences as well.
It is said that especially the wires from the transformer to the diodes, first choke and caps should be short. My chassis is home made at my company so i can make something to mount the first choke on top of the transformer if i can minimize interference by magnetic fields.
I remember long time ago i did move the power transformer from underneath a turntable platter to a position just about 10 inches away. There wasnt a hum in the first place but moving it did improve low level information. So i can guess buying a gaussmeter could be a good a good investment.
My transformer has two identical secundary windings. I can put them in paralellel and using 4 diodes or use 2 diodes and put them in series and use the cetre tap as ground. Which solution will be better?
Sincere greetings, Edward
I’ve opted for parrelleling two secondary winding and 4 diode (good quality bridge diode in my case). This is the design I’ve seen the most in transistor and chip power amp PS’s (Peter Daniel's/Nelson Pass) (4 diodes but not nessesarily a bridge diode). I read an article where, when using a input choke, grounding is best done after this input choke (http://www.emissionlabs.com/datasheets/274-applikation1.htm) . Critical in parrelleling windings is that they are of equal windings/resistance, otherwise a current will start running between them
I’ve re-jigged my PS to run as parallel input choke, second choke still in series. Even with a 15V R-core I had lying around, I’m only getting 9VDC out under load (with a 100Ohm bleeder). I’ve ordered a 2x18 10A traffo instead, in order to be able to use a lower value bleeder to draw more current.
Sound wise, first impression is that the sound is slightly more focused and separation is better, at the expense of timbre and some body/warmth. But the difference is pretty small. Input choke prevents the first caps from getting a high DC ripple so should be easier on them and prolong their life, and overall resistance of the PS is lower.
When I get the new traffo, I hope that with a decent 12Vdc output and proper loading of the chokes with a bleeder pulling more current, the choke input will be the better sounding option.
I’ve re-jigged my PS to run as parallel input choke, second choke still in series. Even with a 15V R-core I had lying around, I’m only getting 9VDC out under load (with a 100Ohm bleeder). I’ve ordered a 2x18 10A traffo instead, in order to be able to use a lower value bleeder to draw more current.
Sound wise, first impression is that the sound is slightly more focused and separation is better, at the expense of timbre and some body/warmth. But the difference is pretty small. Input choke prevents the first caps from getting a high DC ripple so should be easier on them and prolong their life, and overall resistance of the PS is lower.
When I get the new traffo, I hope that with a decent 12Vdc output and proper loading of the chokes with a bleeder pulling more current, the choke input will be the better sounding option.
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Hi Edward,
Many thanks for the tips! Please keep us posted with your findings on the 300VA RCore against typical Torodial or EI tranny. I am particularly keen on these RCore tranny, including the RCore chokes you have mention.
In anticipation for the new DAC/main boards and the Tent Shunts arrival, I have been study Doede schematic. I hope with my engineering background other than electronic/electrical specific, the following implementation idea may yield the sonic benefit. Please correct me if my idea isn't practical or bringing sonic advantage?
1. I will be using Salas Shunt to supply the mainboard, BeagleBone Black with Botic Cape, and WaveIO since I have already paid for the three Salas Shunts from GB. Each will have its own power transformer.
2. For the DAC board, each channel will be supply by a separate power supply with individual transformer.
3. the three i2s input 100R resisters per channel will be replacing to 91R AN tantalum 0.5W.
4. I will follow SuperSurfer's (Stefan) ideology with regards to DAC board modified configuration for TentShunts and unregulated ps wiring.
5. I will be replacing electrolytic caps Muse KZ to ELNA Silmic II or Cerifine.
I also found myself aligned with stijn001, that is paralleling secondaries winding and 4 Schottky diode yield best result.
Best,
Chanh
Many thanks for the tips! Please keep us posted with your findings on the 300VA RCore against typical Torodial or EI tranny. I am particularly keen on these RCore tranny, including the RCore chokes you have mention.
In anticipation for the new DAC/main boards and the Tent Shunts arrival, I have been study Doede schematic. I hope with my engineering background other than electronic/electrical specific, the following implementation idea may yield the sonic benefit. Please correct me if my idea isn't practical or bringing sonic advantage?
1. I will be using Salas Shunt to supply the mainboard, BeagleBone Black with Botic Cape, and WaveIO since I have already paid for the three Salas Shunts from GB. Each will have its own power transformer.
2. For the DAC board, each channel will be supply by a separate power supply with individual transformer.
3. the three i2s input 100R resisters per channel will be replacing to 91R AN tantalum 0.5W.
4. I will follow SuperSurfer's (Stefan) ideology with regards to DAC board modified configuration for TentShunts and unregulated ps wiring.
5. I will be replacing electrolytic caps Muse KZ to ELNA Silmic II or Cerifine.
I also found myself aligned with stijn001, that is paralleling secondaries winding and 4 Schottky diode yield best result.
Best,
Chanh
Hello Stijn,
With a normaql current rating 15 volts transformer you should get more than 9 volts according to me.
With the input choke 2 windings in parralel you will only have 40mH inductance. You will get some voltage loss in the choke because of serie4 restance too. So let us say you will get 12 volts dc after the choke ( that will be 0.8 times 15) With 12 volts and 40mH you will need a total current of 300ma to make it work like a true choke input. With 100ohm you will have 120ma going through the bleeder. Your circuit isnt taking the 180ma left i think.
Are you sure you did wire everything correctly? The 9 volts seems so low to me.
Next week i will get my lundahls so i can run a test and see what voltages i will get.
Yes, i did read a lot of info on chokes and they the common mode is the way to go because the rubbish from the transformer is stopped at both ends of the winding.
A pity Chanh i dont have the dac yet . Did make some heavy investment in audio the last month and i wanna finish a few things first.
Sincere greetings, edward
With a normaql current rating 15 volts transformer you should get more than 9 volts according to me.
With the input choke 2 windings in parralel you will only have 40mH inductance. You will get some voltage loss in the choke because of serie4 restance too. So let us say you will get 12 volts dc after the choke ( that will be 0.8 times 15) With 12 volts and 40mH you will need a total current of 300ma to make it work like a true choke input. With 100ohm you will have 120ma going through the bleeder. Your circuit isnt taking the 180ma left i think.
Are you sure you did wire everything correctly? The 9 volts seems so low to me.
Next week i will get my lundahls so i can run a test and see what voltages i will get.
Yes, i did read a lot of info on chokes and they the common mode is the way to go because the rubbish from the transformer is stopped at both ends of the winding.
A pity Chanh i dont have the dac yet . Did make some heavy investment in audio the last month and i wanna finish a few things first.
Sincere greetings, edward
Just a note to say I haven't ignored this
I have some nice pictures, but I'm on holiday at the moment with almost zero Internet, so can't upload... When I find a moment with some decent access, I'll post a couple of bits up which should explain nicely
I just made some measurements. After my input choke I'm measuring 11.4 Vdc with just a 100 Ohm bleeder, my traffo is actually 14.3 volt (though specified as being 15V), so that's 0.8 reduction according to what Edward predicted. However when I connect the dac, voltage drops to 9.3Vdc at the output of the input choke. The traffo is only rated at 30VA, eventhough larger would better, I expected it should have still have worked up to 2.5A at 12Vdc..
Maybe worth trying with the secondaries wired in full wave centre tap mode using 2 diodes. That should give you a couple of extra volts at the output.
Hello Stijn, James, Chanh and the others,
I remember reading James report, did some '' calculations '' and decided to go for a 300va 2*15 volts r-core being sure that would be enough.
Maybe if you use a low grade, low current rating R-core the voltage would be on the low side. Maybe the core is to small or the craftman did have a bad day?
Anyway with my 300va the voltage will be higher because it is made to deliver 15 volt at a higher current.
With the the bigger lundahl choke for common mode choke input i will probably get about 14 volts at the '' exit '' of that choke. If i will go for 4 boards with shunts i will loose another 2 volts in the second choke. I can always skip some resistors on the board to have less voltage '' reduction '' there.
I think you need about 10.5 volts for the 8 volts shunts if i am right so i still have some headroom.
The bigger choke does have higher resistance (1.7 ohm for each winding) but because of the higher inductance the bleeder only needs to draw 35ma ( 14 volts dc at the first choke divided by 400mH ) With less current inductance will be higher but to be safe you can draw 52ma by using a 270 ohm resistor which will dissipate about 3/4 watts.
Of course filtering will be better with more inductance. The bigger choke is only about 30% more expensive compared to the little one and they have infinite life .
By the way if you draw some current the chokes will get warm too. Have to take care when using ployurethane resin for potting and also not putting the caps to close because they dont like heat. Caps will have an easy life with choke input because the input choke will deal with the ripple.
Mu metal for screening is expensive i did know because i buy it before 2 decades ago but metal prices did go up after China did start using a lot
more.
Happily R-core and lundahl style chokes dont radiate that much. BUT better be safe than sorry so i am still thinking about getting a gaussmeter on the internet after all there are a power transformer, two chokes and a pair of output transformers to deal with.
I am sure that in the end there will be just one or two '' positioning '' of the iron in relation to each other that will give the best results. It could be the first choke that will radiate more than the power transformer.
Sincere greetings, Edward
I remember reading James report, did some '' calculations '' and decided to go for a 300va 2*15 volts r-core being sure that would be enough.
Maybe if you use a low grade, low current rating R-core the voltage would be on the low side. Maybe the core is to small or the craftman did have a bad day?
Anyway with my 300va the voltage will be higher because it is made to deliver 15 volt at a higher current.
With the the bigger lundahl choke for common mode choke input i will probably get about 14 volts at the '' exit '' of that choke. If i will go for 4 boards with shunts i will loose another 2 volts in the second choke. I can always skip some resistors on the board to have less voltage '' reduction '' there.
I think you need about 10.5 volts for the 8 volts shunts if i am right so i still have some headroom.
The bigger choke does have higher resistance (1.7 ohm for each winding) but because of the higher inductance the bleeder only needs to draw 35ma ( 14 volts dc at the first choke divided by 400mH ) With less current inductance will be higher but to be safe you can draw 52ma by using a 270 ohm resistor which will dissipate about 3/4 watts.
Of course filtering will be better with more inductance. The bigger choke is only about 30% more expensive compared to the little one and they have infinite life .
By the way if you draw some current the chokes will get warm too. Have to take care when using ployurethane resin for potting and also not putting the caps to close because they dont like heat. Caps will have an easy life with choke input because the input choke will deal with the ripple.
Mu metal for screening is expensive i did know because i buy it before 2 decades ago but metal prices did go up after China did start using a lot
more.
Happily R-core and lundahl style chokes dont radiate that much. BUT better be safe than sorry so i am still thinking about getting a gaussmeter on the internet after all there are a power transformer, two chokes and a pair of output transformers to deal with.
I am sure that in the end there will be just one or two '' positioning '' of the iron in relation to each other that will give the best results. It could be the first choke that will radiate more than the power transformer.
Sincere greetings, Edward
I'm getting a crackling noise-much like a noisy LP-out of one channel of my DDDac. It was not there previously. I'm using a 4 Board set up with Audio Note 2watt resistors on the load function.
A friend had exactly the same experience and describes his experience 'First I had the Dales, then I installed the audio notes: crackle in the right channel. I then swapped the right and left channel resistors, but the crackle was still in the right channel. I went back to the Dales: problem solved, complete mystery'
Anyone else had this? Any ideas?
David
A friend had exactly the same experience and describes his experience 'First I had the Dales, then I installed the audio notes: crackle in the right channel. I then swapped the right and left channel resistors, but the crackle was still in the right channel. I went back to the Dales: problem solved, complete mystery'
Anyone else had this? Any ideas?
David
Hello,
I did examine the R-core a bit closer. I think they did use the same technique as Lundahl does for their power transformer.
Each coil or winding has half of the total primary side and one 15 volts part. The colis are covered by plastic and scotch tape so in other to let the polyurethane resin cover them completely i did remove most of the tape.
Not sure if i will cover the coil with a copper shield because then the resin wont get through either.
I think i will shorten the wires to the diodes to a minimum and the wires from the diodes to the first choke ( common mode and choke input) too.
I have some high value 100H 25ma chokes from Lundahl which use the same technique that i can use in combination with a multimeter to find the right position in relation to the power transformer.
I need to get the dac boards too of course.
Sincere greetings, Edward
I did examine the R-core a bit closer. I think they did use the same technique as Lundahl does for their power transformer.
Each coil or winding has half of the total primary side and one 15 volts part. The colis are covered by plastic and scotch tape so in other to let the polyurethane resin cover them completely i did remove most of the tape.
Not sure if i will cover the coil with a copper shield because then the resin wont get through either.
I think i will shorten the wires to the diodes to a minimum and the wires from the diodes to the first choke ( common mode and choke input) too.
I have some high value 100H 25ma chokes from Lundahl which use the same technique that i can use in combination with a multimeter to find the right position in relation to the power transformer.
I need to get the dac boards too of course.
Sincere greetings, Edward
Hello David,
Dale are professional resistors. Audio note are maybe a bit more tricky to use.
Could it be a bad solder joint. Sometimes resistors are a little bit to big and the wires much be bend a little to much and the cap part of the resistor will not make a proper contact. Maybe change it one more time.
If the resistor heats up during use the cap could make a kind of on off contact.
Sincere greetings, edward
Dale are professional resistors. Audio note are maybe a bit more tricky to use.
Could it be a bad solder joint. Sometimes resistors are a little bit to big and the wires much be bend a little to much and the cap part of the resistor will not make a proper contact. Maybe change it one more time.
If the resistor heats up during use the cap could make a kind of on off contact.
Sincere greetings, edward
