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Old 26th September 2013, 07:12 PM   #431
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Location: Munich
Default Bridged operation

No surprises.

The first screen shot shows approx. 2kW into 4R.
The output voltage of 256Vpp translates to 91Vrms, which results in more than 2kW power.
Scale: 50V/grid (1:10 probe)

The second screen shot shows 2.3kW into 4R, close to clipping.
The output voltage of 272Vpp translates to 96Vrms, which results in 2.3kW power.
Drop of fs becomes visible.
Scale: 50V/grid (1:10 probe)

The third screen shows 2.6kW into 4R, with massive clipping.
Due to rail sagging the peak voltage is even slightly less than at 2.3kW.
Increase of power is related to trapezoidal wave shape instead of a undistorted sinusodial shape, which lifts the RMS voltage without high peak values.
Scale: 50V/grid (1:10 probe)

The measurements have been done manually with a sinusodial input signal.
The popular burst measurements with 300ms/700ms power/break would slightly lift the limits, but not much.
Attached Images
File Type: jpg 2k_4R.jpg (155.5 KB, 492 views)
File Type: jpg 2k3_4R.jpg (109.6 KB, 465 views)
File Type: jpg 2k6_4R.jpg (161.6 KB, 452 views)
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Old 26th September 2013, 09:09 PM   #432
Cresnet is offline Cresnet  Germany
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Very nice...

I noticed 0.000khz frequency on oscilloscope. is that normal?
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Old 27th September 2013, 07:35 PM   #433
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Yes, that's normal with this scope.
I stopped the scope and the amp before I took the picture.
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Old 19th March 2014, 11:21 PM   #434
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Hi guys,

as a kind of noob in electronics I thought for a while... at the end I'm happy to have made this decision and I'm proud to have built these wonderful amps.
I was looking for a while for some potential amps to power my woofers at 2Ohm. A clean sound and lowest distortion were absolutely essential.
After several nights of soldering and some support from Chocoholic (thanks a lot!!!) we could power the amps, which had a phantastic amplified output until almost 1,3kW @2Ohm.
Although the effort is high and the amp complex, I wonder why not more people have built this wonderful amp.
I hope, Chocoholic won't loose his pleasure and will design another fine amps in the future, which he hopefully will also share with us

Regards,

Stammheim
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Old 22nd March 2014, 12:07 PM   #435
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Quote:
Originally Posted by Stammheim View Post
... at the end I'm happy to have made this decision and I'm proud to have built these wonderful amps...
Again my congratulations.
It is a complex project and you made it almost free of errors!
And you helped to catch inconsistencies/mistakes in my documentation for V1.5.
I will double check again and then publish the builders pack of V1.5 .
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Old 22nd March 2014, 02:41 PM   #436
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Default Builders Pack of V1.5

...here it is..
Attached Files
File Type: zip SystemD_2k4_PcbVendorFiles.zip (152.5 KB, 59 views)
File Type: pdf SystemD_2k4_V1dot5_Power.pdf (152.5 KB, 94 views)
File Type: pdf SystemD_2k4_V1dot_Modulator.pdf (125.5 KB, 91 views)
File Type: pdf SystemD_2k4_V1dot5_Supply.pdf (75.0 KB, 70 views)
File Type: pdf PCB_V1_Front.pdf (206.9 KB, 80 views)
File Type: pdf PCB_V1_Back_seethroughfromtop.pdf (131.1 KB, 64 views)
File Type: pdf PCB_V1_Back_viewfromback.pdf (131.4 KB, 59 views)
File Type: pdf SystemD_2k4_BOM_V1dot5_20140322.pdf (947.0 KB, 87 views)
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Old 23rd March 2014, 10:56 AM   #437
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Quote:
Originally Posted by ChocoHolic View Post
No surprises.

The first screen shot shows approx. 2kW into 4R.
The output voltage of 256Vpp translates to 91Vrms, which results in more than 2kW power.
Scale: 50V/grid (1:10 probe)

The second screen shot shows 2.3kW into 4R, close to clipping.
The output voltage of 272Vpp translates to 96Vrms, which results in 2.3kW power.
Drop of fs becomes visible.
Scale: 50V/grid (1:10 probe)

The third screen shows 2.6kW into 4R, with massive clipping.
Due to rail sagging the peak voltage is even slightly less than at 2.3kW.
Increase of power is related to trapezoidal wave shape instead of a undistorted sinusodial shape, which lifts the RMS voltage without high peak values.
Scale: 50V/grid (1:10 probe)

The measurements have been done manually with a sinusodial input signal.
The popular burst measurements with 300ms/700ms power/break would slightly lift the limits, but not much.
I feel bad for your neighbours

seriously good work, thanks for keeping the diy standards high. reminds me of eva`s work. does anyone know what happened to her ? or are the two of you working together in the silence.
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Old 23rd March 2014, 11:12 AM   #438
pergo is offline pergo  Italy
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Is there any method to do hysteresis control with commercial OTAs?
One of these, for example: Transconductance Amplifier * - Products - TI.com
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Old 23rd March 2014, 10:54 PM   #439
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Quote:
Originally Posted by pergo View Post
Is there any method to do hysteresis control with commercial OTAs?
Basically it should work to take a constant hysteresis through
a voltage divider from the half bridge, then gain it through such a high speed OTA and when the speaker signal comes to large levels then reduce the gain by reducing the quiscient current.
However the nonlinear Iq control characteristic will need to be taken into account.

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Originally Posted by Reactance View Post
...does anyone know what happened to her ?
Sadly I also lost the contact to Eva.
...would love to read of her again.
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Old 24th March 2014, 08:49 AM   #440
luka is offline luka  Slovenia
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Quote:
Sadly I also lost the contact to Eva.
...would love to read of her again.
I could try to contact her via messenger. Should i?
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