what are your recommendations for local decoupling load caps - type and value used after BIB output cap of value 10 - 100 uF
it depends on the load.
If the load can demand sudden changes in current, then local decoupling is mandatory.
If the load current changes slowly, then local decoupling becomes less than mandatory.
Local decoupling at the load has nothing to do with the PSU !
If the load can demand sudden changes in current, then local decoupling is mandatory.
If the load current changes slowly, then local decoupling becomes less than mandatory.
Local decoupling at the load has nothing to do with the PSU !
AndrewT
what about If load Is dac chips and preamp
what I like to see Is what users of BIB place at local loads
what about If load Is dac chips and preamp
what I like to see Is what users of BIB place at local loads
the PSU should be designed to be stable when the current demand changes.
That's as far as the PSU can go. After that, improving, or changing, the PSU has no effect on how the LOAD changes it's DEMAND.
The load determines what local decoupling is needed to minimise distortions of the current consumer to it's own demands on the supply rails. If the DAC is well designed it will already have the necessary decoupling fixed in the correct locations to minimise distortion due to it's own operations.
If it's well designed but built down to a pricew there may be places where improvements to the DAC's decoupling can be made. These DAC changes/improvements have absolutely nothing to do with how the PSU remains stable into changing load currents. That is a completely separate (PSU) design issue
That's as far as the PSU can go. After that, improving, or changing, the PSU has no effect on how the LOAD changes it's DEMAND.
The load determines what local decoupling is needed to minimise distortions of the current consumer to it's own demands on the supply rails. If the DAC is well designed it will already have the necessary decoupling fixed in the correct locations to minimise distortion due to it's own operations.
If it's well designed but built down to a pricew there may be places where improvements to the DAC's decoupling can be made. These DAC changes/improvements have absolutely nothing to do with how the PSU remains stable into changing load currents. That is a completely separate (PSU) design issue
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well I don't want to redesign a PSU
the question Is relation between BIB out cap and local decoupling cap - influence between various types values
the question Is relation between BIB out cap and local decoupling cap - influence between various types values
If you will ever get interference between your gear and the PSU's calculated termination because of near feeding point decoupling and this PSU's large bandwidth, you may try 0.1R in series at the feeding point and/or 100uF across sense wires at the PSU's output connector IF you will see anything weird when scoping the rail. Solid tantalum decouplers are nice.
for an example let take Pass D1 - SM available
It uses electrolytic 220 uF local decaupling caps at psu dac pins
It also uses serial 3 pin regulators at psu
If I want to replace serial 3 pin regulators with BIB with 10 - 100 uF out cap what value Is recommended to use at dac psu pins - original electrolytic 220 uF or something else
It uses electrolytic 220 uF local decaupling caps at psu dac pins
It also uses serial 3 pin regulators at psu
If I want to replace serial 3 pin regulators with BIB with 10 - 100 uF out cap what value Is recommended to use at dac psu pins - original electrolytic 220 uF or something else
BIB using 2sk117
HI, I am going to build a BIB, and to compare to QuangHauo 1.0, in my DAC digital sections (TP Opus, WM8804 receiver). Does BIB better job? I have in my hand 2SK117BL, does it work in BIB or not? Thanks
HI, I am going to build a BIB, and to compare to QuangHauo 1.0, in my DAC digital sections (TP Opus, WM8804 receiver). Does BIB better job? I have in my hand 2SK117BL, does it work in BIB or not? Thanks
BiB Manual
"JFETS/IDSS
Toshiba 2SK117GR is used, has shown better stability as a CCS than 2SK170 in this reg
and more bandwidth. The noise is on par with 2SK170 but the capacitance is half. Its -Vp is
also suitable for the small voltage margins in some crucial positions in this design.
By testing a few, 3-5mA IDSS range in the GREEN(GR) group were plenty.
You should select yours for falling in that range also, by following this tutorial:
Transistor matching
There is no need for strict matching, use your lower ones from the 3-5mA subgroup for
Q102,202,302, your medium ones for Q103,203,303, and your stronger ones for
Q105,205,305. Last but not least, 2SK117GR is currently cheaper and more available."
I doubt you get 3mA with BL grade
"JFETS/IDSS
Toshiba 2SK117GR is used, has shown better stability as a CCS than 2SK170 in this reg
and more bandwidth. The noise is on par with 2SK170 but the capacitance is half. Its -Vp is
also suitable for the small voltage margins in some crucial positions in this design.
By testing a few, 3-5mA IDSS range in the GREEN(GR) group were plenty.
You should select yours for falling in that range also, by following this tutorial:
Transistor matching
There is no need for strict matching, use your lower ones from the 3-5mA subgroup for
Q102,202,302, your medium ones for Q103,203,303, and your stronger ones for
Q105,205,305. Last but not least, 2SK117GR is currently cheaper and more available."
I doubt you get 3mA with BL grade
Thanks, but I have all the stuff in my drawer. In the evening I did find 3 pieces of 2SK117GR too 🙂. I built a BIB with IRF9610 and IRF9530, DC=17 V, R101= 9 ohm/5W, 4 blue LEDs. D 101= 1 red LED, R105 trimmer=5Kohm. Output is 12,6 V, and the dummy load= 94 ohm. Unfortunately I can't adjust the output, red led is off :-(. I measured 2,6 V at R101, 4blue=7,9V. Any thoughts? Thanks.
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No or too weak current in the ref from its associated K117 or the red is put in the wrong way blocking? Blue leds can be noisy VS green, then again only 2V per blue, maybe those GRs are too weak? Did you get their idss before installing?
Sorry, I misstyped, 4 Green LEDs =7.9. I did not measure, going to... Is Q103 the Vref associated K117?
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I do have strong GR-s, all of them has more than 5 mA. Ok, the red led was in the wrong way. Is the BIB guide schematic ok, or the red led anode is on the opposite side than the green one? Thank you very much! Is OsCon SEPC a good Vref?