I've built few tube amps, but low voltage, regulation, chips etc. is area i don't know very well.
I need a PSU for a minimalistic TDA1543 DAC. Somewhere i got motivation for a choke loaded DAC PSU and bought two 5H 75mA chokes. I modeled the situation in PSUD (see pic). I thought i could avoid the LMxx regulator (apparently not the best sounding devices ) and use less capacitance. But now i'm not sure that i'm going to risk running unregulated, frying TDAs along the mains fluctuation.
So i included a reg. I placed it between the chokes, the second one might help to filter LM noise. Does it make a sense? If not, what would be the right way incorporating these two chokes ?
Many thanks,
misok
I need a PSU for a minimalistic TDA1543 DAC. Somewhere i got motivation for a choke loaded DAC PSU and bought two 5H 75mA chokes. I modeled the situation in PSUD (see pic). I thought i could avoid the LMxx regulator (apparently not the best sounding devices ) and use less capacitance. But now i'm not sure that i'm going to risk running unregulated, frying TDAs along the mains fluctuation.
So i included a reg. I placed it between the chokes, the second one might help to filter LM noise. Does it make a sense? If not, what would be the right way incorporating these two chokes ?
Many thanks,
misok
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With 135R after the regulator, load regulation is going to be pretty poor. Put both chokes ahead of the reg and get another, much lower DCR choke to go after the LM reg.
thank you, it makes sense.
but there's a strange thing i can't come across :
1. if i connect DAC chip to 9v battery, it works, draws 50mA as it should, everything sounds OK (even if the voltage is 1V over the max, its just for testing, few seconds, chip runs cool)
2. if i try regulated supply (working, checked) 7-8v, two wallwarts 9v, even an unregulated (but safe) version of the fist one .. always the same fail - the voltage oscillates between 1.7-2.1 V .. not working at all of course.
i have no idea why is that. do anyone has suggestions? i don't know what else to try ..
thanks again
but there's a strange thing i can't come across :
1. if i connect DAC chip to 9v battery, it works, draws 50mA as it should, everything sounds OK (even if the voltage is 1V over the max, its just for testing, few seconds, chip runs cool)
2. if i try regulated supply (working, checked) 7-8v, two wallwarts 9v, even an unregulated (but safe) version of the fist one .. always the same fail - the voltage oscillates between 1.7-2.1 V .. not working at all of course.
i have no idea why is that. do anyone has suggestions? i don't know what else to try ..
thanks again
If the voltage is too low, it may be that much more current is drawn from the power supply than provided for by design.
When you tested the power supplies, was that with a test load (ie - resistor load sized for 50mA at the supply design voltage)?
When you tested the power supplies, was that with a test load (ie - resistor load sized for 50mA at the supply design voltage)?
thank you Ben. that's the first thing that comes to mind, and it's not the case i think. the load resistor was somewhere over 100 Ohms, but the point is, that the circuit behaved the same way even with two another commercial wall-warts (rated 1 and 1.5A). the TDA chip is not drawing more as it should, otherwise it would blow up.
after the first trying i thought it's a LM317 behaving strangely or i've made a mistake assembling it, but everything is ok there, without the load or with the dummy load.
i'm very curious where can those volts disappear.. everytime i check with battery - perfect. (i use the same wiring to connect PSUs and battery)
after the first trying i thought it's a LM317 behaving strangely or i've made a mistake assembling it, but everything is ok there, without the load or with the dummy load.
i'm very curious where can those volts disappear.. everytime i check with battery - perfect. (i use the same wiring to connect PSUs and battery)
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Yes, it does appear strange.
The dac chip voltage requirement is 3v min, 5v typ, and 8v max, and current is 50mA typ and 60mA max according to the data sheet. Perhaps try putting a resistor in series with your battery supply and your other supplies to drop the voltage a bit and use the resistor to measure the current and see what differences you get, if any, between the different supplies.
I suppose the power is connected directly to the chip power pin, with a capacitor to ground at the pin? If you have a capacitor there, perhaps the capacitor may be faulty?
The dac chip voltage requirement is 3v min, 5v typ, and 8v max, and current is 50mA typ and 60mA max according to the data sheet. Perhaps try putting a resistor in series with your battery supply and your other supplies to drop the voltage a bit and use the resistor to measure the current and see what differences you get, if any, between the different supplies.
I suppose the power is connected directly to the chip power pin, with a capacitor to ground at the pin? If you have a capacitor there, perhaps the capacitor may be faulty?
thank you for suggestions.
i've found yet another power supply, from older japanese device of some sort - and it holds 5.2V while DAC pulling 40mA. i'll re-investigate my DIY psu when i have a bit more time (not only because i've put around 90Eur in it)
from what i've read, ideal voltage to run TDA1543 is 7-8v, but for now i'm happy with what i have. in fact i can't imagine improved clarity, air or whatever with more headroom, but experiments will surely come later.
i've found yet another power supply, from older japanese device of some sort - and it holds 5.2V while DAC pulling 40mA. i'll re-investigate my DIY psu when i have a bit more time (not only because i've put around 90Eur in it)
from what i've read, ideal voltage to run TDA1543 is 7-8v, but for now i'm happy with what i have. in fact i can't imagine improved clarity, air or whatever with more headroom, but experiments will surely come later.
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