In such case, you use + output from supply as a ground. So, you connect there amplifier and loudspeaker grounds, and connect that + point (now ground) to the amplifier chassis through 10 Ω NTC or using diode bridge. There are only two connection points at + output. Probably good way would be to join two ground wires for amplifier and loudspeaker at one terminal. I was successfully crimping two AWG16 wires to one Fast-On terminal. Using Phoenix terminal blocks with 6.3 mm pitch, there is a place for two AWG14 wires at minimum.
There will be no real difference in performance with any. But as I can measure insignificant difference in favor of 1800 uF, stick with that. 😀
Not to overlook, for such high idle current, C2 should be 33.000 uF minimum. I can find only one available:
https://hr.mouser.com/ProductDetail.../380LX333M050A082?qs=oQrZyJBXqWGW3hzdL1uRCQ==
Thanks for the guidance. Now I am embarrassed seeing you have this capacitor on the board! I thought it was outboard.
I will look on the schematic more carefully before I ask another one of those questions.
Just saw your post - I figure I will use the 1800uF on the board and augment with outboard caps even nearer the circuit.
Thanks, Tombo
I will look on the schematic more carefully before I ask another one of those questions.
Just saw your post - I figure I will use the 1800uF on the board and augment with outboard caps even nearer the circuit.
Thanks, Tombo
My amplifier does not have a chassis - just a big heatsink from a DYNACO Stereo 400 amplifier per channel. sitting on a Baltic birch plywood board.
Sorry to be so needy - but would this (hopefully) no longer need a connection to the amplifier chassis?
Sorry to be so needy - but would this (hopefully) no longer need a connection to the amplifier chassis?
Connection to chassis is a mater of safety when metal cases are involved, as metal chassis must be by safety regulations, connected to the power/safety earth. You have no metal chassis, but that is still not safe. In case of mains transformer insulation failure (however small chance is that), mains voltage can directly enter power supply, burn through and reach any of other connected audio components you may be touching at that very moment. Life threatening situation.
Power cord has third wire for power earth/safety ground. That wire should be connected to power supply ground through 10 – 20 Ω NTC resistor or diode bridge wired as ground loop breaker.
Power cord has third wire for power earth/safety ground. That wire should be connected to power supply ground through 10 – 20 Ω NTC resistor or diode bridge wired as ground loop breaker.
A design hint: Have you tested different sizes of the smoothing cap. Smaller cap may produce less harmonics. 4700 uF for instance, what will will the result be?
Result will be too much ripple at several A loads, preventing regulator to work at very low voltage drop. 🙂
I don’t see any problem with harmonics at single microvolt levels. Whatever is presented in measurements, is a worst case with low quality transformer, DUT, power amplifier PCB and measurement gear on the bench. The result is that 50 Hz is directly entering high input impedance LNA through cables and that 50 Hz EMI is responsible for most harmonics present in the FFT measurements. It does not originate from the supply output.
Large reservoir capacitors cause high amperage charging pulses and those cause strong electromagnetic fields that induce noise in the supply PCB. I've noticed that with other supplies that use the whole PCB area for tracks/planes.
This is the reason I use as little copper as possible. Everything is a design compromise determined by design goals.
I don’t see any problem with harmonics at single microvolt levels. Whatever is presented in measurements, is a worst case with low quality transformer, DUT, power amplifier PCB and measurement gear on the bench. The result is that 50 Hz is directly entering high input impedance LNA through cables and that 50 Hz EMI is responsible for most harmonics present in the FFT measurements. It does not originate from the supply output.
Large reservoir capacitors cause high amperage charging pulses and those cause strong electromagnetic fields that induce noise in the supply PCB. I've noticed that with other supplies that use the whole PCB area for tracks/planes.
This is the reason I use as little copper as possible. Everything is a design compromise determined by design goals.
Got my boards yesterday. Have installed resistors in four - should have the rest of the insertions done this evening.
Very nice looking boards. Did not mean for there to be the shadow.
This is a bigger board than I expected - compared to the first version.
I have four remaining if there is any interest.
Very nice looking boards. Did not mean for there to be the shadow.
This is a bigger board than I expected - compared to the first version.
I have four remaining if there is any interest.
As far as the capacitor after the rectifier - after seeing the boards - looks like the easiest thing to do is use my existing Zen Mod cap bank plugged into the Tombo board. I will keep them very close to each other.
This is a complete power supply and R21 is just a voltage regulator add-on module.
Twist together connection wires to the external capacitors bank, to reduce radiated electromagnetic noise.
Tombo56, your design deserves a name or a number. “Power Supply with Active Rectifier, RF Filter and Super-Regulator”… Naah.
What about R25?!
What about R25?!
Nope, it is already called “Power supply with no name”. Hint, it can ‘carry you across audio desert’. 😉
Catchy names are a must in commercial audio, but I feel that they are just a marketing attempt to cover mediocre performance.
Rare exclusion are great names for great circuits by Zen Mod.
Catchy names are a must in commercial audio, but I feel that they are just a marketing attempt to cover mediocre performance.
Rare exclusion are great names for great circuits by Zen Mod.
A specific name/number makes discussion and comparison way easier. Especially if there was a previous design called R21. Or a next version “Improved Power Supply with Active Rectifier, RF Filter and upgraded Super-Regulator”.
True. But I just decided to not bother with name. Folder on my PC actually has R25 designation. You can use that reference if it makes things easier. 🙂
I will for sure. Made a product in the past with a random name that could have been used for many purposes but the name gave a wrong impression. Also not optimal.
R25 it is then.
R25 it is then.
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Tombo,
The interactive BOM tool is super cool.
Thanks for including all the support for this project in a neat and tidy folder.
....also added the 'R25' designator 🙂.
The interactive BOM tool is super cool.
Thanks for including all the support for this project in a neat and tidy folder.
....also added the 'R25' designator 🙂.