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Old 9th August 2011, 11:17 PM   #141
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... and corresponding schematics related to upper slew rate sim result.
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Last edited by Lazy Cat; 9th August 2011 at 11:23 PM.
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Old 10th August 2011, 12:14 AM   #142
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Quote:
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OK thanks AJ, corrected.
Not quite Lazy Cat. Sorry if my post wasn't clear. I would have posted a sketch and a reference but I was at work. This method is from Bob Cordells recent book, pg.351. His supply is little more complicated using double the electrolytics, but applying it to your PS you'd have something like the attached diagram.

The main point of this method is it gets the main star connection away from the high currents flowing between the filter caps, giving a better, cleaner gnd reference point. Like I said minor change to your diagram, but it makes a big difference when it comes to laying out a PCB.
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Old 10th August 2011, 12:21 AM   #143
AKSA is offline AKSA  Australia
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Lazy Cat, Nico,

Brilliant, off the wall contribution..... a great amp!!

I particularly like the mosfet/bipolar output stage, it inserts a EF output which is always preferable for difficult loads (ie speakers!).

At the cost of adding some distortion, you could slightly increase one of the 10R CCS resistors (R3 or R4 in the above schemat) to 12R to deliberately drive the harmonic profile towards even artefacts; this would 'warm' it up a little.

Cheers,

Hugh
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Old 10th August 2011, 07:05 AM   #144
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Thanks for the compliment Hugh.

Regards

Nico
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Old 10th August 2011, 11:09 AM   #145
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Quote:
Originally Posted by Stormrider View Post
Not quite Lazy Cat. Sorry if my post wasn't clear. I would have posted a sketch and a reference but I was at work. This method is from Bob Cordells recent book, pg.351. His supply is little more complicated using double the electrolytics, but applying it to your PS you'd have something like the attached diagram.

The main point of this method is it gets the main star connection away from the high currents flowing between the filter caps, giving a better, cleaner gnd reference point. Like I said minor change to your diagram, but it makes a big difference when it comes to laying out a PCB.
Yeah the GND point, it certainly should be the zero-reference potential for the load and the unbalanced input since we try to make a comparison between them, differing only in a gain factor. It is logical that the messy ripple current flowing near smoothing capacitors should not interfere with any of them especially with the input bias current since these two are like David and Goliath. So the distance preventing the last modulate the weak one is reasonable solution.

Thanks to point out this again to clarify the problem, appreciate it, will be considered at PCB designing process.
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Old 10th August 2011, 11:31 AM   #146
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Quote:
Originally Posted by AKSA View Post
Lazy Cat, Nico,

Brilliant, off the wall contribution..... a great amp!!
Thanks a lot Hugh, I am honoured with your presence, it positively influences the project.

Quote:
Originally Posted by AKSA View Post
I particularly like the mosfet/bipolar output stage, it inserts a EF output which is always preferable for difficult loads (ie speakers!).
I share the same thoughts as you are. BIGBT even has EF&CF combined in a parallel manner, equally loading the mosfet driver.

Quote:
Originally Posted by AKSA View Post
At the cost of adding some distortion, you could slightly increase one of the 10R CCS resistors (R3 or R4 in the above schemat) to 12R to deliberately drive the harmonic profile towards even artefacts; this would 'warm' it up a little.

Cheers,

Hugh
Will try that soon in sim to see the change in a harmonic distortion profile result. Thanks for the tip, Cheers.
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Old 11th August 2011, 01:11 AM   #147
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..... I'm glad to show you my latest PCB , late hours , I'm going to sleep now
Alex.
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Old 11th August 2011, 01:15 AM   #148
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I Like this amp a lot. I like laterals anyway and i sometimes need a little compact amp. When it is ready i will build it. Keep the Laterals at the output. That is the charm. Even the first version. Great work on the PCB by the way. It looks really tidy.
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Old 11th August 2011, 02:41 AM   #149
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Hi AlexMM,

Very nice & compact PCB. I may build this to compare to my Goldmund clone.

The connectors for the 24V AC seems to take up a lot of real estate. I suggest to use only one terminal connector & two quik-on for each rail.

The max diameter for the 10000uF filter cap is only 20mm, that will limit the choice. I suggest to move the filter caps by 3mm so that we can install caps up to 25mm diameter.

Cheers, Stanley
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Old 11th August 2011, 03:44 AM   #150
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If I want to use 4 of 5 pairs of output laterals, what should be changed?
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