Hi Viorel, first thanks for making this video based on my comment on the other video, much appreciated, as well as the good explanations you provide! Many thanks! Still I realized this is slightly beyond what I have at hand to do it myself 😅, I found an alternative transformer from another brand which is compatible (I'll just need to adapt the connection).
A centre tapped transformer is not needed. Grab an 18VAC 1A single winding plug pack, wire one side to the ground pin and the other side to both of the other two pins. It'll still make +/-24volts for the regulators. If you can't get 18VAC and don't care about having 48v phantom power (32v will do), use a 12vac plug pack and change the regulators on the mixer board from 7815/7915 to 7812/7912. The rectification will make +/- 16.4V, well above the offset needed for 7X12 regulators (and a lot less heat dissipation on them than before).
Well...for a farm use it's perfect, those tiny analog ICs, which by the way are working differential, means a double voltage related to ground...once there is single wing, they will deliver half of the wave and also half of the signal...with all the distortions on the way. But as long it sounds good to your particular ears, that’s fine! Go to it!
@@viocaia Not quite. The rectification will still make the required +/- voltages, it's just done alternatively at 50 times a second, not simultaneously at 100 (half-wave rectifying not full wave). The split winding is not required and a single will do as long as one of the winding sides is wired where the centre-tap used to go.. The analog opamps will still get the full +/- Vcc needed. I've done this on many of their mixers as the normal power supply is hard to get. Lowering the transformer winding voltage only affects the phantom power voltage made in the capacitive doubler.
I admit it's working like that, but the overall performances will degrade, also sensible higher hum in the signal. I'm not debating the solution you describe, I just wonder if this is feasible why Behringer is not implementing on their products, so they can save costs and sell with same price! just wonder.
Hello, thank you for your explanation, very good video, I have a question that I would appreciate if you could answer. When measuring it with the voltmeter, my power supply shows 21 to 24 V instead of what you mention of 17 or 18V. The XLR inputs on the audio console stopped working. Is it possible that my power supply is bad? and has that made the entries no longer work? Everything else is perfect, even the 1/4 inputs and the console works very well. Thanks for your help.
It's normal to show more than 21V AC, the voltage goes down after rectifier to DC and regulators. 48V for XLT+R it's supplied by a internal circuit, I don't have the schematic. BUt look for a capacitor like 1000uf at 75 or more V, that should be related to phantom and check the parts around.
Right! The output, it's alternating current. Most of the wall power supplies comes with direct current, this one has no rectifier and filters on board, bare AC.
Hi Viorel, first thanks for making this video based on my comment on the other video, much appreciated, as well as the good explanations you provide! Many thanks!
Still I realized this is slightly beyond what I have at hand to do it myself 😅, I found an alternative transformer from another brand which is compatible (I'll just need to adapt the connection).
Perfect, as long as there are 2 x AC voltage from 15 to 19V it should work. All the best!
Thank you for teaching us you are very professional from phillipines MABUHAY!!!
@@JoselitoRocero No teaching, just helping.Thanks!
A centre tapped transformer is not needed. Grab an 18VAC 1A single winding plug pack, wire one side to the ground pin and the other side to both of the other two pins. It'll still make +/-24volts for the regulators. If you can't get 18VAC and don't care about having 48v phantom power (32v will do), use a 12vac plug pack and change the regulators on the mixer board from 7815/7915 to 7812/7912. The rectification will make +/- 16.4V, well above the offset needed for 7X12 regulators (and a lot less heat dissipation on them than before).
Well...for a farm use it's perfect, those tiny analog ICs, which by the way are working differential, means a double voltage related to ground...once there is single wing, they will deliver half of the wave and also half of the signal...with all the distortions on the way. But as long it sounds good to your particular ears, that’s fine! Go to it!
@@viocaia Not quite. The rectification will still make the required +/- voltages, it's just done alternatively at 50 times a second, not simultaneously at 100 (half-wave rectifying not full wave). The split winding is not required and a single will do as long as one of the winding sides is wired where the centre-tap used to go.. The analog opamps will still get the full +/- Vcc needed.
I've done this on many of their mixers as the normal power supply is hard to get. Lowering the transformer winding voltage only affects the phantom power voltage made in the capacitive doubler.
I admit it's working like that, but the overall performances will degrade, also sensible higher hum in the signal. I'm not debating the solution you describe, I just wonder if this is feasible why Behringer is not implementing on their products, so they can save costs and sell with same price! just wonder.
@@saddle1940 Nice to know!
Mister Viorel the first time I heard your voice it reminds me on the voice of Wolfgang Flür from Kraftwerk . 🎉
Really, I live Kraftwerk, I didn't notice that.
@@viocaia serious !
@@ChromosomeSyndicate of course!
Hello, thank you for your explanation, very good video, I have a question that I would appreciate if you could answer. When measuring it with the voltmeter, my power supply shows 21 to 24 V instead of what you mention of 17 or 18V. The XLR inputs on the audio console stopped working. Is it possible that my power supply is bad? and has that made the entries no longer work? Everything else is perfect, even the 1/4 inputs and the console works very well. Thanks for your help.
It's normal to show more than 21V AC, the voltage goes down after rectifier to DC and regulators. 48V for XLT+R it's supplied by a internal circuit, I don't have the schematic. BUt look for a capacitor like 1000uf at 75 or more V, that should be related to phantom and check the parts around.
@@viocaia thanks for you answer!!!! thank you!
@@edgarjnev Anytime.
18.5 250ma would be ok for a 1202fx?
Kind of limit, but it should work...you need a double 18.5V AC !
AC = Alternating Current?
Right! The output, it's alternating current. Most of the wall power supplies comes with direct current, this one has no rectifier and filters on board, bare AC.