JW
Well-known member
Hey folks,
I'm trying to rig up Mnats' little PSU for +/-16VDC, and I can only get +/-13V.
Here's a link to the little PSU. http://mnats.net/psu.html (I'm using the newer, double sided version, but as far as I can tell they're the same)
I'm using this power transformer: http://hairballaudio.com/shop/product_info.php?cPath=33&products_id=89&osCsid=844899acf45eba49eee66c26b9530391
The secondary, loaded with the power supply reads at 21VAC.
My questions are:
1. Did I pick the wrong power transformer in that I need a center tap? (for which there is a tab on the Mnats board)
2. Mnats says: "LED current setting resistors R1, R2 are for the +30/-10 volt supply. If you are using different output voltages you should calculate the correct value for R1 and R2 for the typical voltage on each output."
I'm not using the LED's, so I went ahead and left these resistors out. At one point I tried a couple different values thinking that these resistors were necessary but there was no effect on the voltages, so I gather I can leave them out if I don't need the LED's?
3. The G1176 specifies +30V/-10V. I'm using this supply for a solid state Pultec w/ API style amp, which is why I need +/-16V. I had 5K trimmers in R3 and R5. Maxed out, these trimmers only allowed for about +/-13V as I mentioned. I'm pretty new to understanding this stuff, but I'm guessing that the resistance here limits the current and raises the voltage when resistance is increased? I took out the trimmers and experimented with upwards of 220K on each side with no change in voltage at all. Do I just need to go higher?
What am I doing wrong?
I'm trying to rig up Mnats' little PSU for +/-16VDC, and I can only get +/-13V.
Here's a link to the little PSU. http://mnats.net/psu.html (I'm using the newer, double sided version, but as far as I can tell they're the same)
I'm using this power transformer: http://hairballaudio.com/shop/product_info.php?cPath=33&products_id=89&osCsid=844899acf45eba49eee66c26b9530391
The secondary, loaded with the power supply reads at 21VAC.
My questions are:
1. Did I pick the wrong power transformer in that I need a center tap? (for which there is a tab on the Mnats board)
2. Mnats says: "LED current setting resistors R1, R2 are for the +30/-10 volt supply. If you are using different output voltages you should calculate the correct value for R1 and R2 for the typical voltage on each output."
I'm not using the LED's, so I went ahead and left these resistors out. At one point I tried a couple different values thinking that these resistors were necessary but there was no effect on the voltages, so I gather I can leave them out if I don't need the LED's?
3. The G1176 specifies +30V/-10V. I'm using this supply for a solid state Pultec w/ API style amp, which is why I need +/-16V. I had 5K trimmers in R3 and R5. Maxed out, these trimmers only allowed for about +/-13V as I mentioned. I'm pretty new to understanding this stuff, but I'm guessing that the resistance here limits the current and raises the voltage when resistance is increased? I took out the trimmers and experimented with upwards of 220K on each side with no change in voltage at all. Do I just need to go higher?
What am I doing wrong?
