Me and some other guys at a swedish forum have a question regarding a schematic for 3 LM3886. I think that this schematic is correct: http://www.leetmaa.se/misc/q1.pdf
But there is them who claims that this one, http://www.leetmaa.se/misc/q2.pdf is the way to go.
Witch should it be?
But there is them who claims that this one, http://www.leetmaa.se/misc/q2.pdf is the way to go.
Witch should it be?
Hi,
both those amp schematics are based on inverting topology.
Zin for inverting is the series resistor/s feeding the inverting input pin.
For one amp this is 1k+9k=10k
For three in parallel this is 10k//10k/10k=3k3.
The DC blocking cap (4u7F) sees a load of 47k//3k3=3k1.
The F-1dB of that filter is ~22Hz.
The inverting topology has killed the bass response.
4u7F should be increased to around 56uF for extended bass response.
But, can the pre-amp or source feed a Zin=3k1 load impedance?
My answer is neither.
both those amp schematics are based on inverting topology.
Zin for inverting is the series resistor/s feeding the inverting input pin.
For one amp this is 1k+9k=10k
For three in parallel this is 10k//10k/10k=3k3.
The DC blocking cap (4u7F) sees a load of 47k//3k3=3k1.
The F-1dB of that filter is ~22Hz.
The inverting topology has killed the bass response.
4u7F should be increased to around 56uF for extended bass response.
But, can the pre-amp or source feed a Zin=3k1 load impedance?
My answer is neither.
http://www.national.com/an/AN/AN-1192.pdf
Hi, what is wrong with the arrangement on page 8 ? ,
/sreten.
Hi, what is wrong with the arrangement on page 8 ? ,
/sreten.Ok i get the point. This schematic then? Any thoughts about that?
An externally hosted image should be here but it was not working when we last tested it.
Hi Andrew and thank you for the time you put in to answering al my silly questions
I have made some thinking and please correct me if im wrong, but wouldnt this be a more correct way to aply the RF-filter: http://www.leetmaa.se/misc/qp.pdf
Many thanks...
I have made some thinking and please correct me if im wrong, but wouldnt this be a more correct way to aply the RF-filter: http://www.leetmaa.se/misc/qp.pdf
Many thanks...
Carl, have you studied the AN-1192 and also understood it? Personally I have used a buffer in front of these LM3886 and you have both space and the supply voltage which makes it easy for you.
I would also make a complete bridge connected circuit on the same pcb. It's a clear advantage to minimize the wiring, both when it comes to making errors in building and also picking up noise, RFI etc.
I would also make a complete bridge connected circuit on the same pcb. It's a clear advantage to minimize the wiring, both when it comes to making errors in building and also picking up noise, RFI etc.
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