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Old 4th September 2012, 04:44 PM   #791
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Hi Routhan,

kindly would you take a measurement of a 100 Hz and 20 Hz square waves, this may give some indication of the low frequency response.
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Old 5th September 2012, 05:13 AM   #792
routhun is offline routhun  United States
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Hello Mr. Nico,

I couldn't take the measurements tonight, I'll capture them in a day or 2 and post here.

Thanks,
Routhun
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Old 5th September 2012, 04:10 PM   #793
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Join us for an exciting adventure. Put your ears to the test.(Your feedback is really needed) Tell us all about it and advance the state of the art. Join us for round 2. http://www.diyaudio.com/forums/group...oup-thing.html
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Old 5th September 2012, 04:48 PM   #794
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Hi Harrison/Routhun,

the test I am proposing is not to show up anything bad in the amplifier, I would not do that. What I am suspecting is that the low frequency strain on the power supply would be exactly what is being discussed in the reservoir capacitor thread and what looks like 20 000uF/rail on the photo.

The only reason I asked for the test is that it seemed that routhun was already set-up to do another test. If you have already closed up routhun then do not bother, we will catch someone else who may be about to test an amp.
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Old 5th September 2012, 04:54 PM   #795
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Quote:
Originally Posted by routhun View Post
Hello Mr. Nico,

I couldn't take the measurements tonight, I'll capture them in a day or 2 and post here.

Thanks,
Routhun
Hi Routhun, if the square wave test shows bad results do not try and solve it, just show us. I am very keen to see how the reservoir caps rail hold up in a real test. Remember that the test must be into a load else the test is useless.
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Old 5th September 2012, 06:16 PM   #796
routhun is offline routhun  United States
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Hi Nico,

Power supply reservoir capacitors are 18000uf,50v panasonics. The total capacitance in this amp is 72000uf for both the channels. I am measuring the waveforms with 8 ohms pure resistive load connected to the output. Any case I'll measure and upload the results soon.

Thanks,
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Old 5th September 2012, 06:30 PM   #797
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Quote:
Originally Posted by routhun View Post
Hi Nico,

Power supply reservoir capacitors are 18000uf,50v panasonics. The total capacitance in this amp is 72000uf for both the channels. I am measuring the waveforms with 8 ohms pure resistive load connected to the output. Any case I'll measure and upload the results soon.

Thanks,
Hi Routhun,

It will definitely be interesting to see the output waveform with so much capacitance per rail.

Would maybe support Gootee's forecast that under power supply stress conditions there may not be enough time to recharge the capacitors. Besides it would be of as much interest to your fellow SYMEF constructors. Thanks for participating Routhun.

Sorry for highjacking your thread Harrison.
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Old 8th September 2012, 05:34 PM   #798
routhun is offline routhun  United States
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Default SYMEF measurements

Hi Nico,

Here is the square response of SYMEF at 20hz, 100hz, 10khz and 20khz into 8ohms pure resistive load.

Thanks
Attached Images
File Type: jpg SYMEF-20hz.jpg (899.7 KB, 291 views)
File Type: jpg SYMEF-100hz.jpg (423.9 KB, 248 views)
File Type: jpg SYMEF-10khz-2.jpg (735.8 KB, 231 views)
File Type: jpg SYMEF-20khz-2.jpg (515.0 KB, 204 views)
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Old 8th September 2012, 07:59 PM   #799
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Thank you very much Routhun. I trust that you found this low frequency response both unexpected and puzzling. However, your scope is on AC coupled please use DC coupled else the effect is accentuated by the probes high pass filter. I would like to see your power supply's effect on the low frequency.
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Last edited by Nico Ras; 8th September 2012 at 08:12 PM.
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Old 9th September 2012, 02:16 AM   #800
routhun is offline routhun  United States
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Default SYMEF measurements with DC mode

Hi Nico,

Thank you for correcting me it was my mistake, I was using the AC input mode thats why square wave response is not great at lower frequencies. Now I measured again with DC input mode, now the response looks much better.

Thanks,
Attached Images
File Type: jpg SYMEF-20Hz-DC.jpg (374.3 KB, 171 views)
File Type: jpg SYMEF-100Hz DC.jpg (904.2 KB, 29 views)
File Type: jpg SYMEF-1Khz DC.jpg (900.0 KB, 36 views)
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