I have a 12 Volt AC to AC wall wart.
Any idea what I could get for final voltage with the VRDN?
Hoping I can maybe get +-15VDC.
Or is my max voltage +-12VDC?
Any idea what I could get for final voltage with the VRDN?
Hoping I can maybe get +-15VDC.
Or is my max voltage +-12VDC?
Last edited:
The VRDN is a Voltage Regulator (with De-Noiser) will not output more voltage than the input.
Your max voltage will be ±12VDC.
Your max voltage will be ±12VDC.
12VRMS * sqrt(2) = 16.97V peak (+16.97 to -16.97)
minus 2 diode forward voltage drops @ 0.7V each --> 15.57V peak
minus peak-to-trough ripple voltage --> about 15V trough voltage
minus LM317 / LM337 input-to-output voltage drop (a/k/a "dropout voltage") --> about 12V DC
minus 2 diode forward voltage drops @ 0.7V each --> 15.57V peak
minus peak-to-trough ripple voltage --> about 15V trough voltage
minus LM317 / LM337 input-to-output voltage drop (a/k/a "dropout voltage") --> about 12V DC
Thanks for the math, Mark. I appreciate the actual details!
LOL My Newark order which included some LM337TG was supposed to ship in early October. Just checked my account over there: shipping date updated to December 21.
Webpage still showing:
Available for back order
More stock available to supplier lead times which is approximately 9/25/23
Does Newark have a clue? My experience, No.
I have these parts on backorder also.
Does the VRDN have enough juice to power TWO of the the BA 2018 line stages? I've stuffed (but not tested) two boards for a symmetrical balanced version, hence the question. If need be, I could use two VRDN supplies, powered off a sufficiently beefy transformer, but that'd mean building another one of those, too....
VRDN: bipolar regulator PCB for line level ckts: ±11V to ±20V @ 1.5A with "De-Noiser"
Let me rephrase that for you:
Is 1.5 amperes enough juice to power TWO of the BA 2018 line stages?
@rikiheck
If you search the original WBA18 thread, I had mentioned the current draw of this circuit. And yes, it is exactly as 6L6 states. Needless to say, 1500mA supply capability is more than enough. As a general rule, most of these small line level discrete circuits and also opamp circuits don’t draw much power so the VRDN has likely universal compatibility.
Best,
Anand.
If you search the original WBA18 thread, I had mentioned the current draw of this circuit. And yes, it is exactly as 6L6 states. Needless to say, 1500mA supply capability is more than enough. As a general rule, most of these small line level discrete circuits and also opamp circuits don’t draw much power so the VRDN has likely universal compatibility.
Best,
Anand.
I've made a VRDN PSU but it did not make stable output with onsemi 317, 337 and a toroidial transformer 25VA 18-0 dual secondary.
It happened also with connecting the jumpers of bypassing denoiser.
Did I make any mistaks?
It happened also with connecting the jumpers of bypassing denoiser.
Did I make any mistaks?
Attachments
I wouldn't worry too much about a $50 multimeter whose displayed output voltage flickers between 18.00V and 17.99V. But if you remain deeply, deeply concerned/worried, you could (A) load the outputs with resistors-to-ground which draw approximately the same current as your final audio gear will draw from VRDN; and also (B) monitor the output waveform with an oscilloscope instead of a multimeter.
For example, if your application calls for VRDN to deliver 25mA to the left channel +18V supply, and another 25mA to the right channel +18V supply, that's a total of 50mA from VRDN's +18 output. Ohm's Law tells us that a 360 ohm resistor has the same current draw {math: 18V = 0.05A * 360 ohms} so if you've got a 330 ohm or 390 ohm or 360 ohm resistor, connect it between VRDN +18V and ground, to achieve a same-current load.
For example, if your application calls for VRDN to deliver 25mA to the left channel +18V supply, and another 25mA to the right channel +18V supply, that's a total of 50mA from VRDN's +18 output. Ohm's Law tells us that a 360 ohm resistor has the same current draw {math: 18V = 0.05A * 360 ohms} so if you've got a 330 ohm or 390 ohm or 360 ohm resistor, connect it between VRDN +18V and ground, to achieve a same-current load.
Unfortunately, it's near-on impossible to find such a thing in a thread with nearly 4000 posts.