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 Chip Amps Amplifiers based on integrated circuits

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diyAudio Member

Join Date: Dec 2001
Location: Germany
Quote:
 paulb, Then would adding 2 resistors as a voltage divider suffice to create the split rails? __________________ Leadbelly
Well somehow it would. Never tried it with a poweramp and I think it´s not the way to go.
BTW:Where are the +-23V coming from?
I think you´d still get around 46.5V.

Regards
Jens

 12th May 2003, 04:03 PM #22 diyAudio Member   Join Date: Oct 2002 Location: Croatia hi, your half wave rectifier can work teoreticaly. You put 3ohm resistor and get huge current, biiiiiig ripple, and small, teoreticaly good DC voltage on output (18V). Better (and I think only practical) solution with this transformer is using stabilizated power supply. Regards
 12th May 2003, 04:11 PM #23 diyAudio Member   Join Date: Dec 2001 Location: Germany Just looked it up to be sure: One way rectifying will give you about VDC=1,2*VAC=39,6V. So where´s the +-23V and the 18V coming from????? Jens
 12th May 2003, 04:52 PM #24 diyAudio Member     Join Date: Dec 2002 Location: Calgary, Alberta zx3chris, Your simulations are way off. What you are simulating is the case where the load is overcoming the capacitance, and that's why your DC voltage is lower than VAC*2^0.5. Simulate the "one way symmetric" example with big capacitors and ignoring one of the outside taps. __________________ The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts. Bertrand Russell
diyAudio Member

Join Date: Dec 2001
Location: Germany
Quote:
 VAC*2^0.5
VAC*(2^0.5)
Before anybody gets confused calculating like mad.

Jens

diyAudio Member

Join Date: Jun 2001
Location: Calgary
Quote:
 Originally posted by joensd Well somehow it would. Never tried it with a poweramp and I think it´s not the way to go. Works "well" with a headphoneamp. BTW:Where are the +-23V coming from? I think you´d still get around 46.5V. Regards Jens
A voltage divider approach would only work properly if the current from the ground terminal is much less than the current through the divider resistors.
You may be able to get away with it by using big caps across the divider resistors (as in the "Cmoy" headphone amp), but I still think you'd have to waste a lot of heat in the resistors for it to work properly.

 12th May 2003, 09:52 PM #27 diyAudio Member   Join Date: Oct 2002 Location: south amboy nj i did do simulation with big capacitors and the voltage approaches 46v--i was trying to get a lower dc voltage, which i can do this way but it isnt steady--i need a better tranny or a chip that can take a higher voltage -chris
 12th May 2003, 10:27 PM #28 diyAudio Member     Join Date: Dec 2002 Location: Calgary, Alberta zx3chris, I can't say it many more times: ignore 1 of the transformer taps. And read how many other posters have said that too. When you put on big caps, the supply behaves properly...so you approach 33VAC*(2^0.5) which is where your 46 is coming from. By putting on small caps to intentionally drop the DC, you are creating a wickedly poor supply that will not do a good job because the DC voltage is jumping around like crazy if looked at on a small time scale. If you use the "one way symmetric" example with big caps, you will get about 46 volts...but as 2 rails of +/- 23V. __________________ The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts. Bertrand Russell

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