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Class D Switching Power Amplifiers and Power D/A conversion

Class D amp with 300v mosfets
Class D amp with 300v mosfets
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Old 11th October 2017, 04:02 PM   #21
ionutgaga is offline ionutgaga
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It was a sunny day. I lost the usb cable and I got used to it, with pictures taken with the phone. A screen capture on the oscilloscope would look probably more "scientifically", but as it is now, looks more like diy.
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Old 11th October 2017, 06:30 PM   #22
ChocoHolic is offline ChocoHolic  Germany
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I'm happy with the result.
Enjoy.
...and don't forget to invite your neighbours to the party.
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Old 11th October 2017, 08:53 PM   #23
ICG is offline ICG  Germany
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Do you have measurements, waveform data to enlighten us about the very effect you are talking about, since I fail to see a rise in distortion in my multi kilowatt module with ferrite beads. We might learn something new from you?
Firstly, I did not say it will, I said it can increase distortion. Secondly, the hysteresis of the ferrite beads is, what suppress parasitic oscillation, this is, what you want. What you don't want is to drive the cores into saturation because they drop in inductance if it happens. That causes two things (well, actually more but these are the main issue here), your choke does not work like it did non-saturated, which can cause noise, or oscillation. The second effect it can have is that it might affect the behaviour of the FETs, to be more exact, the rise time can change. That means your dead time, depending on the adjustment you've chosen, might become critical. Again, I did not say it will happen but it can.

Measurements of saturated inductances (not specifically the ferrite beads you were mentioning though): Measurement of coil saturation and inductance | Rauschfunk
The datasheets of the used beads can probably provide information on how close you come to saturation.
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Old 11th October 2017, 11:46 PM   #24
doctormord is offline doctormord  Germany
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Where/How should it increase distortion when mounted over the gate/drain legs and used in this configuration? You're talking about total different effects which occur when using ferrites/inductors iNLINE in high current applications - which totally isn't the case here. The other effect of resonance peaking will need some high Q capacitance after the ferrite.

Last edited by doctormord; 11th October 2017 at 11:50 PM.
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Old 12th October 2017, 06:51 AM   #25
ionutgaga is offline ionutgaga
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Enjoy.
...and don't forget to invite your neighbours to the party.
I have made this amplifier for full range speakers in general, but as an immediate application, it will amplify these Seeburg k2 nd (and their clones).

http://www.seeburg.net/pdfs/produktp...enblatt_dt.pdf

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The impedance of these speakers requires some resources from the amplifier:
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Last edited by ionutgaga; 12th October 2017 at 06:57 AM.
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Old 12th October 2017, 02:37 PM   #26
Eva is offline Eva  Spain
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This is looking quite satisfactory.

It seems we have some disciplines in common. I have been fully dedicated to creation of next generation of class D amplifiers for 10 years, with no free brain resources for progress in sound systems, but this could change in the future.

btw: the cabs in the floor are all LF, the smaller driver is closed back, just to cover the hole, and I also happen to have an unfinished 2nd channel, cloned mid horn
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Old 12th October 2017, 05:01 PM   #27
ionutgaga is offline ionutgaga
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I'm glad to see someone with a similar hobby!
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Old 12th October 2017, 05:29 PM   #28
Eva is offline Eva  Spain
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I think there is a misconception here. A hobby is a nerd renting a system from a nerd, to play popular mass market tracks made by and for nerds, who pay the renting and some more, as the only way to enter in contact with exemplary designs and philosophies. Producing the high tech personally is a though discipline.
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Old 12th October 2017, 07:27 PM   #29
ChocoHolic is offline ChocoHolic  Germany
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the cabs in the floor are all LF
Somehow the horn on the floor is catching my immediate sympathy.

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Producing the high tech personally is a though discipline.
Is it wrong to do so not for money but for joy+brain food and calling it a hobby?
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Old 13th October 2017, 05:47 AM   #30
ionutgaga is offline ionutgaga
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I think there is a misconception here. A hobby is a nerd renting a system from a nerd, to play popular mass market tracks made by and for nerds, who pay the renting and some more, as the only way to enter in contact with exemplary designs and philosophies. Producing the high tech personally is a though discipline.

My so-called hobby, I have mentioned, includes besides making various speaker constructions and processing their sound either by making passive filters or choosing a combined passive-active filtering method, or full active filtering and processing . The real challenge is to make a speaker sound good, or sound like another speaker taken as a reference, knowing and identifying correctly what are the acoustic anomalies and which ones can be corrected acoustically (through various modifications, including but not limited to shape changes, addition of sound absorbing material, surface damping, addition of acoustic reflectors, horn shape change for the driver, etc.), or electric through the various filtering and equalizing methods, taking into account the directivity of the speaker as a whole. Last but not least, considering that each speaker has a specific timbre, sometimes portions of the frequency range that do not sound properly, these shortcomings must be identified, and the total measured acoustic response may not resemble that of another speaker to sound the same. There is much to say, but I stop here because I do not want to completely change the direction of this topic.
Now, that's what I call hobby.
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