There is options for that described in http://www.diyaudio.com/forums/power-supplies/192625-sslv1-1-builds-fairytales-103.html#post2945885
Hi guys, I have a Apogee Mini-dac, which uses a DC input in the range 9-14V. I built a ALW super reg and that powered it without problems. I have built a REFLEKTOR, set to 10V (which is confirmed with a multimeter) and that causes the DAC to display error lights. Any ideas? Is it cause current is set to low? If so, what is the easiest way to adjust this?
By making the resistor between B,E of the 4403 or BC560 (R1) smaller the current goes up. ICCS=VBE/R1. Make sure you got a raw DC decoupling cap like 0.1uF film very close to the reg's DCin physical nodes too.
5 Vdc for Raspberry, squeezebox, etc... 1-2Aamp.
Thanx Stajo ! -Giving me a few hours of learning 🙂
Well i found the xls -calc, and tried to fill in my values.
I WILL (i think) use a 12vac tranny, 2sk170Gr (-which i have)
The PI uses 700mA for normal operation.
Can anyone have a look at the spreadsheet ?
I also stumbled upon a schematic in thread, where Salas have simulated a 5vdc out shunt (I have attached this in the .zip -file)
/Thanks - Jesper
Thanx Stajo ! -Giving me a few hours of learning 🙂
Well i found the xls -calc, and tried to fill in my values.
I WILL (i think) use a 12vac tranny, 2sk170Gr (-which i have)
The PI uses 700mA for normal operation.
Can anyone have a look at the spreadsheet ?
I also stumbled upon a schematic in thread, where Salas have simulated a 5vdc out shunt (I have attached this in the .zip -file)
/Thanks - Jesper
Thanks Salas, so you referring to a 0.1uF bypass cap on the main smoothing cap after rectification of the input AC?
i get voltage sag trying to power this circuit with bib 1.1
peter's circuit's altered with 10 piggyback 1543s on each side, 20 total. the shunt reg is set at 6v. when i take the chips out the red leds come on and the v is healthy, when the chips go back in the red leds are off and the voltage sags to 2v.
weird thing is the reg works fine with 5piggyback chips, even 9 on one side, but 10, no go. i have multiple batches of 10 piggyback chips so i don't think that's the cause. r101 is 3.3ohm, but input diodes are unknown types that i salvaged and setup for half-wave rectification; which sound i always prefer.
maybe the diodes are the reason?
peter's circuit's altered with 10 piggyback 1543s on each side, 20 total. the shunt reg is set at 6v. when i take the chips out the red leds come on and the v is healthy, when the chips go back in the red leds are off and the voltage sags to 2v.
weird thing is the reg works fine with 5piggyback chips, even 9 on one side, but 10, no go. i have multiple batches of 10 piggyback chips so i don't think that's the cause. r101 is 3.3ohm, but input diodes are unknown types that i salvaged and setup for half-wave rectification; which sound i always prefer.
maybe the diodes are the reason?
How much current is the circuit drawing? What is the incremental draw going from, say 5 chips to 8 chips?
What you are describing is what happens when you try to draw more current than the regulator can supply. The red LED's go out and the regulator drops out of regulation. You need to look at the input AC voltage, how much current your transformer can supply, and how much current you are demanding from the reg. Assuming the transformer is OK you might need to lower R101 a little more.
What you are describing is what happens when you try to draw more current than the regulator can supply. The red LED's go out and the regulator drops out of regulation. You need to look at the input AC voltage, how much current your transformer can supply, and how much current you are demanding from the reg. Assuming the transformer is OK you might need to lower R101 a little more.
trafo is 2 40va paralleled for 80, supplying 12v.
1543 is 60ma max so 1.2a + lm7805 and lm317 post regs that draw less than 100ma combined.
So you dont think the zeners are issue? I had lowered r103 to 2ohm before with no success
1543 is 60ma max so 1.2a + lm7805 and lm317 post regs that draw less than 100ma combined.
So you dont think the zeners are issue? I had lowered r103 to 2ohm before with no success
Get measurements. See about your actual CCS setting by Ohm's law (VR101/R101=CCSmA), see about your actual load consumption by interfacing a very small value resistor you got in your stash between the reg and the load. Solder it at the power receiving end of the load and use the same equation as for CCS. Measure the raw DC at input side across the big filter capacitor when the thing is fully loaded so to know if the trafo ducks. Maybe there is a short somewhere and over-current occurs. Or the many chips draw more than you may think. You would need at least 100mA more CCS ability than max load consumption to get it going decently.
seems like 9 tda1543s are the limit. r101 is 2ohm, i dare not go lower since my heatsinks are barely adequate. i would have loved to feed 20 1543s with a single reg 🙁
Can't you project some new bigger heatsink? The burden in your case is on the CCS heatsink by the way if you got them split.
i lowered the input ac to 9v and everything is nice and cool. no subjective sq difference from 12v i hear.
You are still in the >5VDC dif recommended zone. Sounds like a good trade off for heat given your sinking limitations.
sorry for bunch of questions but what drawbacks are there for running bjt output at 5v+? id like to compare the sonic differences of both types of outputs powering tda1543 at 8v.
also is there any to-2 type of transistor that can be substituted for the output?
thank you.
also is there any to-2 type of transistor that can be substituted for the output?
thank you.
BJT in this gives more output impedance but also more bandwidth VS MOSFET. A con and a pro. Depends on what your circuit likes more of the two traits. Better try between transistor and MOSFET than different from the recommended transistor type. Don't forget to use the right (different value) gate/base stopper resistor for either type of output as explained in the BOM.
DACS with oversampling usually, yet their layout and decoupling plays a primary role. More OLG BW=More of level Zo portion towards very high frequencies.
Salas i have problem with one shunt, the CCS-set leds doesn't light up, and i have tried changing the 2SK117's to new ones. And checked that the 270R / 47R resistors are ok. must be damaged MOSFET?
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