I cannot say what the audible result is for combining the wires, I have made too much changes at the same time to be able to distinguish the effects.
In theory combining this will be better. Though it looks the same in a schematic, the real world of wires/pcb traces is a complex thing that can transmit and recieve all kinds of signals (interference) so the less wires the better.
And it also makes room for the shunt
Of course, it is a bleeder.
I am not so sure that a resistor would be "slower" than a semiconductor.
Just for the sake of investigation - I have never seen a regulator with a flat output impedance vs. frequency. I would suspect the resistor, assuming high quality, low temperature coefficient, by itself, would be the embodiment of linearity and being in parallel with the output of the regulator would tend to flatten the curve just as putting a resistor in parallel with a loudspeaker flattens the impedance curve. Not that I make a habit of doing this, but it is analogous.
I am sorry you think I am trying to champion series regulators. Hardly. I do not much care for any regulator since all of them are flawed as is everything else in the world. I have never NOT heard a regulator. They all leave their fingerprints on the sound. They all add a more "electrical" sound but we put up with them to get what they do better than brute force passive power supplies especially when voltages must be controlled.
In the digital world we are stuck with them.
I do not doubt the shunts are better but how much better is the question. I will try them when I get a response from Mr. Tent.
From what I have read both types are seriously compromised by distance from the circuit. So one can wonder: how much difference there is between the two when there is an inch between the reg and the "circuit"/DAC? Something to consider?
I am not so sure that a resistor would be "slower" than a semiconductor.
Just for the sake of investigation - I have never seen a regulator with a flat output impedance vs. frequency. I would suspect the resistor, assuming high quality, low temperature coefficient, by itself, would be the embodiment of linearity and being in parallel with the output of the regulator would tend to flatten the curve just as putting a resistor in parallel with a loudspeaker flattens the impedance curve. Not that I make a habit of doing this, but it is analogous.
I am sorry you think I am trying to champion series regulators. Hardly. I do not much care for any regulator since all of them are flawed as is everything else in the world. I have never NOT heard a regulator. They all leave their fingerprints on the sound. They all add a more "electrical" sound but we put up with them to get what they do better than brute force passive power supplies especially when voltages must be controlled.
In the digital world we are stuck with them.
I do not doubt the shunts are better but how much better is the question. I will try them when I get a response from Mr. Tent.
From what I have read both types are seriously compromised by distance from the circuit. So one can wonder: how much difference there is between the two when there is an inch between the reg and the "circuit"/DAC? Something to consider?
Rick,
I installed three 3.3v SJM Bellesons on my DDDAC digital circuits without a "pull down resistor" and experienced a huge improvement in sq. I installed a 56uf polymer cap and 0.1 bypass film cap just before each of them to provide fast release energy. I changed no caps after the small Bellesons which fit nicely on the LF33 pads.
They are powered by a 6.3v 2amp transformer which filters up to 7.5 volts at about a 0.1v ripple into this load which is also supplying a 5 volt SPJ Belleson at the input to my WaveIO. I lifted the 22 ohm resistors and inductors and did not have to cut any foil. I feed the 7.5v into the original 12VDC location on the main board to feed the 3 digital voltage regulators.
The analog side of the PCM1794s are powered by an 8vdc Salas shunt power supply. My DDDAC is incredibly analog sounding. IHMO, the Bellesons should not be considered a step down from shunt power supplies on the DDDAC digital circuits.
Ross
I installed three 3.3v SJM Bellesons on my DDDAC digital circuits without a "pull down resistor" and experienced a huge improvement in sq. I installed a 56uf polymer cap and 0.1 bypass film cap just before each of them to provide fast release energy. I changed no caps after the small Bellesons which fit nicely on the LF33 pads.
They are powered by a 6.3v 2amp transformer which filters up to 7.5 volts at about a 0.1v ripple into this load which is also supplying a 5 volt SPJ Belleson at the input to my WaveIO. I lifted the 22 ohm resistors and inductors and did not have to cut any foil. I feed the 7.5v into the original 12VDC location on the main board to feed the 3 digital voltage regulators.
The analog side of the PCM1794s are powered by an 8vdc Salas shunt power supply. My DDDAC is incredibly analog sounding. IHMO, the Bellesons should not be considered a step down from shunt power supplies on the DDDAC digital circuits.
Ross
To get 20mA @ 8V you need to install a 400 Ohm resistor, maybe i'm wrong, but i guess this is the 'impedance' of the sink. The output of the DAC see 133 Ohm or lower depending on how many boards in use.
Maybe it is possible to use a R + FET or R + Z-Diode to lower the 'impedance' of the sink.
Anothe question came in my mind, why not keep it simple and use a R + Z-Diode 'shunt' to get the 8V ?
Regards
Marcus
Maybe it is possible to use a R + FET or R + Z-Diode to lower the 'impedance' of the sink.
Anothe question came in my mind, why not keep it simple and use a R + Z-Diode 'shunt' to get the 8V ?
Regards
Marcus
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These arrived today courtesy of Charlie @ Big Bear Audio, so it's new power supply time very soon
I'm going to try the same unregulated, low impedance CLCLC method as Stefan as that should be the perfect raw supply for my shunt regs
An externally hosted image should be here but it was not working when we last tested it.
I'm going to try the same unregulated, low impedance CLCLC method as Stefan as that should be the perfect raw supply for my shunt regs
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I tried to find 2,200uf Silmics as Stefan had used, but Silmics haven't been made in that size for some time, so I opted for 6 x Panasonic FM 2,200uf 25v and I'm going to run them in pairs.
Excellent, I came to the same conclusion on the caps. I'm not sure what you mean with 6 X in pairs though.
"if" I splash out on the 700 odd euro's to populate my 4board Dac with the Tents shunts, I'm thinking about a CRC supply filter instead of a CLC. I'm not convienced there is enough of a difference in it to justify the cost of the chokes over a few resistors.
So each 'C' stage of the CLCLC is 2 x 2,200uf Caps instead of 1 x 4,700uf.
Like this:
Right, IC, thanks for the picture, I hadn't realised Stefan used a CLCLC configuration.
why no choke input?
Hello,
I always did like the power supplies with a choke input.So the choke directly after the rectifier.
It might be wise to use a bleeder to always a steady current flow that you need to make it work like a choke input.
The data sheet of the lundahl choke says it can be used as a choke input too.
With my power amp that uses a shunt regulation too adding a choke input was a big step ahead. The late Allen Wright of vacuum state electronics did always advice to use a choke input in combination with his superreg shunt power supply.
Just try.
Sincere greetings, edward
Hello,
I always did like the power supplies with a choke input.So the choke directly after the rectifier.
It might be wise to use a bleeder to always a steady current flow that you need to make it work like a choke input.
The data sheet of the lundahl choke says it can be used as a choke input too.
With my power amp that uses a shunt regulation too adding a choke input was a big step ahead. The late Allen Wright of vacuum state electronics did always advice to use a choke input in combination with his superreg shunt power supply.
Just try.
Sincere greetings, edward
Thanks,
Yes, I plan to use a bleeder resistor after the second choke. I only have 1 dac deck with shunts and measured my load from the current 12v power supply as 270mA, so I plan to use a 24ohm bleeder to draw another 500mA and put the Lundahls more into their effective operating range.
I plan to just mock up the new choke power supply quickly at first, so I can try a few different ways, so I will try LCLC too. I have a cheap usb oscilloscope, so I was going to try and check the voltages at various points and see how/if the voltages after the shunts are effected by the various options. I'll measure with the current power supply too so I have a base measurement.
I'm pretty crappy at comparative listening tests, so it'll be nice if I can also have some measurements to back stuff up
Hello James,
The bleeder it will get hot. I am very bad with formulas.
What i always did do is using a bleeder that will have enough current draw that even without the actual circuit attached the power supply will still function as a choke-input.
When there is less current the induction of the choke will be higher ( depends on the air gap if i am right).
You need a minimum value to have it work like a choke input. If the number of mH is to low the voltage will rise to much.
You will need a higher secondary voltage but transformer are not expensive. I remember reading in French that an ordinary EI one would be better because of more narrow bandwith.
It would be nice if you could compare two supplies with the same number of caps and chokes just different transformers( to compensate the voltage loss). One LCLC and one CLCLC ( an extra cap).
When my present projects are finished i will probably do the same. Have some chokes left that i did use in Virtue Sensation m901 Now using 40AH batteries. With this tripath amp batteries are better. With the DAC they were not that i good ( that is what is did read)
Attachment is my choke input power supply ( 100mH, 1A potted chokes)
Sincere greetings, Edward
The bleeder it will get hot. I am very bad with formulas.
What i always did do is using a bleeder that will have enough current draw that even without the actual circuit attached the power supply will still function as a choke-input.
When there is less current the induction of the choke will be higher ( depends on the air gap if i am right).
You need a minimum value to have it work like a choke input. If the number of mH is to low the voltage will rise to much.
You will need a higher secondary voltage but transformer are not expensive. I remember reading in French that an ordinary EI one would be better because of more narrow bandwith.
It would be nice if you could compare two supplies with the same number of caps and chokes just different transformers( to compensate the voltage loss). One LCLC and one CLCLC ( an extra cap).
When my present projects are finished i will probably do the same. Have some chokes left that i did use in Virtue Sensation m901 Now using 40AH batteries. With this tripath amp batteries are better. With the DAC they were not that i good ( that is what is did read)
Attachment is my choke input power supply ( 100mH, 1A potted chokes)
Sincere greetings, Edward
Attachments
Yes, I understand they will get pretty hot... Stefan explained to me 12v x 0.5A = 6w
So I got a 7w wire wound resistor and also (because it's nice and easy to mount externally if needed) a 50w one too
So I got a 7w wire wound resistor and also (because it's nice and easy to mount externally if needed) a 50w one too
An externally hosted image should be here but it was not working when we last tested it.
so I'll try the 7w first and see how hot it gets
I always prefer choke input supply whenever possible and this dac is no exception
besides I find it strange that many thinks the local reg will fix anything coming down stream from a mediocre psu
with a choke input psu, they´ll be fed much cleaner dc to start with
my dac psu is 200va 2x34vac-2x MUR860 bypassed with Silmics, Hammond 159Y and then into a 22KµF Mundorf AG elytic in the position of C3 in the original supply...C7 and C8 are replaced by a Panasonic Fc 1000µF/35vdc
WaveIo has 24vac secondaries and the rest is the same
onboard regs are all original
sounds great imo
best
Leif
besides I find it strange that many thinks the local reg will fix anything coming down stream from a mediocre psu
with a choke input psu, they´ll be fed much cleaner dc to start with
my dac psu is 200va 2x34vac-2x MUR860 bypassed with Silmics, Hammond 159Y and then into a 22KµF Mundorf AG elytic in the position of C3 in the original supply...C7 and C8 are replaced by a Panasonic Fc 1000µF/35vdc
WaveIo has 24vac secondaries and the rest is the same
onboard regs are all original
sounds great imo
best
Leif
Hello James,
If it dissipates 6 watt 7 watt will be to small for sure.
Just use the 50 watt one on a big heatsink.
YES Leif even with the shunts from Allen wright switching to a choke input was a very big step forward. But he always did advice to do so in his books.
But still you don't see may choke input around. Probably i will wait for the new dac board that will be easier with the shunts from Mr Tent.
Will start with choke input almost sure!
Sincere greetings, Edward
If it dissipates 6 watt 7 watt will be to small for sure.
Just use the 50 watt one on a big heatsink.
YES Leif even with the shunts from Allen wright switching to a choke input was a very big step forward. But he always did advice to do so in his books.
But still you don't see may choke input around. Probably i will wait for the new dac board that will be easier with the shunts from Mr Tent.
Will start with choke input almost sure!
Sincere greetings, Edward