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Old 12th September 2012, 10:26 AM   #1081
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by AP2 View Post
This is a fantasy that a psu with transformer, drop only 1-5V. sorry for this. if you have measure, please show.
It seems from your various posts that you have gone down the regulated PSU route. It also appears that you have rejected all forms of linear PSUs as being suitable for audio power amplifiers.

If you have never seen Vdrops of 1V to 5V in a linear, unregulated PSU when driving full power into the specified load, then you have not investigated thoroughly.
They exist. I have some.
You obviously don't have any.

It further seems that if any Member dares to disagree with your SMPS "rules" view, that they are all wrong.
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Last edited by AndrewT; 12th September 2012 at 10:42 AM.
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Old 12th September 2012, 10:27 AM   #1082
AndrewT is offline AndrewT  Scotland
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Originally Posted by danielwritesbac View Post
............For drainer resistor and a bonus light: ..........
What?
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Old 12th September 2012, 10:34 AM   #1083
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Quote:
Originally Posted by AP2
This is a fantasy that a psu with transformer, drop only 1-5V. sorry for this. if you have measure, please show.
i am with AP2....in my super leach amp, i used a power traffo with 2inch center leg stacked 3inches....very heavy transformer....

full power testing with both channels putting out 45 volts ac into an 8 ohm load showed that standby rails of +/-85volts dropping to +/-72 volts.....

Click the image to open in full size.
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Old 12th September 2012, 04:18 PM   #1084
AP2 is offline AP2  Italy
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Quote:
Originally Posted by Tony View Post
i am with AP2....in my super leach amp, i used a power traffo with 2inch center leg stacked 3inches....very heavy transformer....

full power testing with both channels putting out 45 volts ac into an 8 ohm load showed that standby rails of +/-85volts dropping to +/-72 volts.....

Click the image to open in full size.
Hi, thank Tony...nice job. this your drop voltage 13V is familiar for me and reflect my last pic also.
AndrewT: no..i not have rejected linear psu (as concept),infact i have develop ultra fast regulator for it.
i reject unregulated, independant it is smps or linear.
Market push on new solution, then some companies invest in this direction.
at 50Hz i have calculate a hole of energy(min)=8ms.(just for acceptable 5V of drop under load,if we fill this hole of energy)
show me your solution (exclude big inductance for shift phase)

Last edited by AP2; 12th September 2012 at 04:22 PM.
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Old 12th September 2012, 04:32 PM   #1085
AP2 is offline AP2  Italy
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Originally Posted by AndrewT View Post
It further seems that if any Member dares to disagree with your SMPS "rules" view, that they are all wrong.
I'm sorry, I do not agree with what you say. I "accept disagreements about my work), they are clearly documented. I do not accept lies, especially if they come from incompetent people.
I do not force a smps for lamps into audiophile use of amplifier.
I do not hiden emi/rfi becouse are very poor.
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Old 12th September 2012, 04:34 PM   #1086
AndrewT is offline AndrewT  Scotland
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Theoretically, or simple model if you prefer, 30mF will deplete ~33.3mV/ms/Arms.
For a 3.5Arms load (98W into 8r0) and a duration of 9ms, the smoothing cap will deplete by ~1V

Then you need to make a more sophisticated model to better reflect actual PSU performance.

Instead I simply measure the PSU voltage. 1V to 5V is pretty common for my unregulated linear PSUs.
As I said earlier
Quote:
you have not investigated thoroughly.
or you too would have found similar by actual measurement.
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Old 12th September 2012, 04:50 PM   #1087
AP2 is offline AP2  Italy
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Quote:
Originally Posted by AndrewT View Post
Theoretically, or simple model if you prefer, 30mF will deplete ~33.3mV/ms/Arms.
For a 3.5Arms load (98W into 8r0) and a duration of 9ms, the smoothing cap will deplete by ~1V

Then you need to make a more sophisticated model to better reflect actual PSU performance.

Instead I simply measure the PSU voltage. 1V to 5V is pretty common for my unregulated linear PSUs.
As I said earlieror you too would have found similar by actual measurement.
I'm sorry, in this thread, there are people who can understand very well,a complex model, I have no doubt about it.
If you have this psu done well, is very easy to show the behavior during the peaks and the continuous absorption. maybe even a picture, just to see how big it is.
----------------
How You write "instead of simple measure volts?"
my last pic, can give you a lot of information also in ref to timing, perhaps you've only read the voltage?

and, one big capacitors, can help with the first impulse of mainstream (or single repeated in agreemet with period of recharge), after this, I want to see the charging time, especially in repetition (as is the music signal)

Last edited by AP2; 12th September 2012 at 05:02 PM.
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Old 12th September 2012, 05:41 PM   #1088
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I am definitely not any expert or even close but it now appears that we are getting into an argument about two opposing trains of thought here. I see the latest picture of the power amp with what looks like a single large power supply capacitor. This seems to be going against what I thought that I had been following of smaller parallel capacitor banks,whether all together, in a CRC configuration or in a distributed large capacitor, smaller capacitor at the output device location. It would appear that this simple question could be answered with a simple test. One amplifier as a control with a fixed transformer size, large enough to handle the power demands. Then using one manufacturers capacitors with identical construction methods, make one experiment with a single large capacitor and another with multiple smaller capacitors of the exact same total capacitance. Select a time frame that is sufficient to show the results over time with a high demand and show the scope patterns so we can compare apples to apples. Just what I would like to see with only one variable changing in a scientific test.

Steven
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Old 12th September 2012, 06:47 PM   #1089
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This has been by far one of the most interesting threads I have followed. I think it would imply that there is still no consensus reached or a simple rule of thumb found.

Steven, your request is very valid and I do not think that any of us have amplifiers at the ready to make power supply alterations to without major effort and for that reason I would like to call on Harrison in this regard.

Harrison has a few threads running where members are building his amp designs with his freely supplied PCBs. (I commend you for that)

I would ask of Harrison to request from the assemblers that is currently busy building his amps and have access to a scope to make some measurement with the aim to confirm the fact that a few smaller caps are more desirable than one larger cap. I think this will put that question to bed.

We can then focus on the next possibility and so eliminate the variables practically one by one on the recommendations from our esteemed DIY members that has been contributing so unselfishly to this thread.

I also think that Harrison's group will benefit from this exercise.
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Last edited by Nico Ras; 12th September 2012 at 06:55 PM.
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Old 12th September 2012, 08:31 PM   #1090
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I am humbled Nico . This being diy its a great place to meet, make new friends learn, research, share and have fun. You must have come across this Free PCBs

We just have to match our theory to practical implementation. A lot has been said about PCB layout in this thread and any member is free to offer what they think is the best layout for the designs.

AP thanks for sharing with us your amp. As you can see there is a big disjoint between theory and practical implementation. What would you say is the inductance of those interconnect cables, is the amp worse off ? AP also seems fine with film across the big boys. Does the amp display unruly behaviour ? What do the ears hear ?
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