Dear All,
Does anyone know where I can find a good +/- 35V Power Supply schametic? I'm trying to build a Chip amp that runs off 70V. Can't seem to find any schematics on something like this.
Does anyone know where I can find a good +/- 35V Power Supply schametic? I'm trying to build a Chip amp that runs off 70V. Can't seem to find any schematics on something like this.
Look at Rod Elliot's Site, ESP, just scale the transformer to suit the DC voltage you want. Divide the DC voltage by the square root of two to find the AC voltage required from the transformer.
Would this one work? Variable Dual Lab Power Supply because it has voltage regulators in it, so that makes me kinda skeptical. And when you mean divide the DC voltage by square root of two, would that be 35V or the total 70V?
Power Supply for Power Amplifiers
I would look at this one it covers the basic concepts. Those regs have a limit of 40V from their lowest to highest potential.
I was hopeing he would have a supply with a transformer with dual secondaries.
http://phonoclone.com/diy-guide.html
Look at the image under VSPS power supply to see how to handle the transformer side with 2 secondaries.
I would look at this one it covers the basic concepts. Those regs have a limit of 40V from their lowest to highest potential.
I was hopeing he would have a supply with a transformer with dual secondaries.
http://phonoclone.com/diy-guide.html
Look at the image under VSPS power supply to see how to handle the transformer side with 2 secondaries.
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Did a quick Google for "+/- 35vdc power supply". Got 43 thousand hits. You could have a look. Must be a schematic in there some where.
Well, that beats the purpose of this forum. As I see it, Sh00pus asked forum members for opinion and advice and he should have it. We all know how to google it B-)
AC values are often given as the RMS (root mean square) value, which is the "power delivery" or "heating" value. When you have 120VAC coming out of your wall socket that is 120V RMS, which is really (120V)(1.414) = 170V peak [sqrt(2) = 1.414 of course]. And since the waveform is sinusoidal that is (170V)(2) = 340V peak-to-peak.
On the other side of the transformer that same magic applies but in a different way. If you have 25VAC coming out of each half of the secondary that is still 25VAC RMS, or (25V)(1.414) = 35V peak or 70V peak-to-peak. The magic here is that the filter capacitor charges to that peak value after going through the bridge rectifier, giving you around 35VDC, as long as you don't load it down more than the current rating of the transformer secondary.
Hope this helps!
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Depending on which chipamp you are planning to build the LMXXX or LMXXXX regulators may not allow enough current to flow into the chipamp when driven hard.
A 25v-0v-25v (or 50v ct) transformer will work just fine. jer
A 25v-0v-25v (or 50v ct) transformer will work just fine. jer
All true and correct info, but what is the current rating of the secondary? It's nVA at 25Vrms. So if that is converted to 35VDC, the current must be derated. For a bridge/cap circuit it becomes roughly nVA/1.8=nW. You can't get somethin' for nothin'.
I got in a a hurry, and not being a math whiz in the first place, I somewhat misstated the equations. Secondary current rating is nVA/25vrms = yA in amperes. The bridge/cap circuit produces roughly yA/1.8 = xA direct current. xA times 35vdc = ~n watts. DC watts will always be less because the circuit has losses and isn't 100% efficient. (If this isn't an improvement I'm giving up 🙂 )
You'd likely want a transformer in the 250 to 300VA range.... I know it sounds like overkill, but this is the overkill forum.
300VA toroidal transformers are readily available in Oz and probably in the land of milk and honey (and huge burgers) so that would be my first port of call. Use a 25V AC transformer for +-35V DC.
As suggested, please read the ESP website for all the information you will need. Apex Jr on the Vendors Forum has capacitors for the job too, very cheap for a lot of capacitance!
What worries me though is you say you have a chip that runs on 70V. Not that I am all that well informed but what chip are you using?
Frank
As suggested, please read the ESP website for all the information you will need. Apex Jr on the Vendors Forum has capacitors for the job too, very cheap for a lot of capacitance!
What worries me though is you say you have a chip that runs on 70V. Not that I am all that well informed but what chip are you using?
Frank
Here is a schematic for a +/- 35 vdc power supply on a chip amp website project. I am including the web link for additional information. Unfortunately your response does not supply any relevant technical information. I am not so sure that Sh00pus can apply your opinion and advice as to the purpose of this forum for DC power supply questions.
An externally hosted image should be here but it was not working when we last tested it.
A 120 Watt Bridged
Sh00pus, that chip can run off 84 V IF you do split the supply. It will cause you problems if you do attempt to run it from that voltage. A +-35V DC supply will be fine if the driver impedance isn't too low. Read the ESP web site and the laboratory supply is not the preferred solution. Post 4 by digits is what you should use. I do with success.
Frank
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