Hi Luvdunhill,
I built the positive one and have problems: the trafo is 18v which give me 28dc at the input of the reg.
I can measure 14.45v at the output of the reg but the leds don't light and i think i should have 18v at the output no ?
I'm using the LM334 and LT 1009, LT1029.
Voltage measured at the top of RF2 is 9.37V....should be 5V ?
Can you give me the correct voltage values for the different points of the circuit so i can debug this ?
I built the positive one and have problems: the trafo is 18v which give me 28dc at the input of the reg.
I can measure 14.45v at the output of the reg but the leds don't light and i think i should have 18v at the output no ?
I'm using the LM334 and LT 1009, LT1029.
Voltage measured at the top of RF2 is 9.37V....should be 5V ?
Can you give me the correct voltage values for the different points of the circuit so i can debug this ?
What is the value of R1, R2, R7 and what is the load on the regulator (if any)? These values depend on the desired output voltage and current, so there isn't really a way I can give you the operating points of the circuit unless I know these target values.
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Hi,
values are as in schematic: R1 is 39R, R2 is 68R and R7 is 4k7...for 18V
for 15V R7 is 1K5 right ? i also want to build one for that value.
but what puzzles me now most is the fact that i measure 9.37V at leg 2 of RF2
when i should be measuring 5 v i think.
There is 1.2 V at the terminals of led 1...not enough...and led 2 has a few milivolts...
values are as in schematic: R1 is 39R, R2 is 68R and R7 is 4k7...for 18V
for 15V R7 is 1K5 right ? i also want to build one for that value.
but what puzzles me now most is the fact that i measure 9.37V at leg 2 of RF2
when i should be measuring 5 v i think.
There is 1.2 V at the terminals of led 1...not enough...and led 2 has a few milivolts...
hm. did you install the diodes on the back of the board? Can you verify that the PNP and NPN parts are not mixed up? Also, in case the silk is somewhat confusing, for the positive channel the flat face of U1 should be facing left for the LM334
...hello,...anybody home ?
Hi!
No, you're already pretty close to 15v, do you really need exactly 15.0v? If you do, then you'll have to parallel another resistor and try and get closer to 4K87, which is what the sim says will output 15v.
Hi,
No i don't need exactly 15V , this is more than good enough for my IV boards.
The sound is much more open, fast and clean with this reg than with the simple cap multiplier i had before.
Although some very high frequency noise is audible once in a while in one of the channels....this i'm still investigating...probably due to rat's nest layout of the IV at the moment.
Next week will have PCBs for the whole thing and can test a much cleaner implementation.
Don't think it's oscilation because other chanel is very clean.
No i don't need exactly 15V , this is more than good enough for my IV boards.
The sound is much more open, fast and clean with this reg than with the simple cap multiplier i had before.
Although some very high frequency noise is audible once in a while in one of the channels....this i'm still investigating...probably due to rat's nest layout of the IV at the moment.
Next week will have PCBs for the whole thing and can test a much cleaner implementation.
Don't think it's oscilation because other chanel is very clean.
I received a number of questions regarding my version of this regulator: I am currently using 4 regulator boards running at 30 Volts (two positive and 2 negative regs). I made some slight amendments which you can easily see if you compare this circuit to the previous one in post 562:
Basically, I moved the compensation cap C6 and added a resistor R5 of ca. 10 Ohms in series. The phase margin looked better in simulation. And I removed a cap and resistor and have now a single resistor R2 to bias Q5. I am using 9.1 Volt Zeners as voltage references. Most component values are not critical and I used what I had, except compensation caps C6 (and R5) and C9, C3 should be at least 470µF, R6 can be from 1-10 Ohms and the higher value reduces gain (see also below). If you set the circuit to different voltages and/or currents you need to watch dissipation in the components.
As a warning: I had one regulator board which was oscillating, and the oscillation coupled into the other three regulators via the long umbilical cord to the raw supply, so they too started to oscillate. Increasing the emitter resistor R6 to 10 ohms (reducing gain) for this one regulator cured the oscillations. Why one reg. was oscillating while the others where not is not clear to me. At any rate, if you decide to use the circuit you should be able to check for oscillations, but this is probably a good idea with any regulator.
Basically, I moved the compensation cap C6 and added a resistor R5 of ca. 10 Ohms in series. The phase margin looked better in simulation. And I removed a cap and resistor and have now a single resistor R2 to bias Q5. I am using 9.1 Volt Zeners as voltage references. Most component values are not critical and I used what I had, except compensation caps C6 (and R5) and C9, C3 should be at least 470µF, R6 can be from 1-10 Ohms and the higher value reduces gain (see also below). If you set the circuit to different voltages and/or currents you need to watch dissipation in the components.
As a warning: I had one regulator board which was oscillating, and the oscillation coupled into the other three regulators via the long umbilical cord to the raw supply, so they too started to oscillate. Increasing the emitter resistor R6 to 10 ohms (reducing gain) for this one regulator cured the oscillations. Why one reg. was oscillating while the others where not is not clear to me. At any rate, if you decide to use the circuit you should be able to check for oscillations, but this is probably a good idea with any regulator.
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