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First One - mosFET amplifier module

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Lazy Cat

Lazy Cat

Member
Joined 2007
Lazy Cat

Lazy Cat

Member
Joined 2007
miero said:
Why do you think that placement of GND connector is important and worth of mentioning, but placement of power supply connectors and related rails are not? Was the EM field generated by them considered during the PCB design phase?
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BTW every little detail is important and there are hundreds of them.
I see you're quite intrigued by PCB layout of power amps, EM fields, etc., the best way would be to study different PCBs from quality amps to learn how to design one of your own. If you like, most convenient way to study First One's PCB is to buy one or two modules and voila.
 
H

hose4

Member
Joined 2013
taccodude said:
Last Night I found out ,when I turn off the Amp,there`s a Tone out of the Speakers ,which starts loud and gets quieter ,till it`s gone.
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I think that is normal. When the power supply voltage goes down the amp develops some kind of audible oscillating sound.

When LC was demonstrating his prototypes we discovered that lower supply voltages made amp less stable than higher. He made modifications to the pcb and during normal operation amps is ok. During switch off some tone is there up to 30 seconds.

I use smps1200a180. If you are good with soldering iron there is a mod which could help. Ask LC for info.
 
Lazy Cat

Lazy Cat

Member
Joined 2007
taccodude said:
Noise is still there ,just tried some different wiring,but doesn`t make a difference.Calibration is not so easy,the Spot are so tiny and my smallest Screwdriver doesn`t fit.What about the Mod Hose4 told?
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When SMPS turned off there's high ripple on SMPS output rails, causing potential audible tone, since speakers are directly connected, no relay contacts in between. But that is very rare, all amps I assembled don't have this or any other noise. It looks you will have to perform recommended calibrations as per manual, eventually.
 
H

hose4

Member
Joined 2013
taccodude said:
Noise is still there ,just tried some different wiring,but doesn`t make a difference.Calibration is not so easy,the Spot are so tiny and my smallest Screwdriver doesn`t fit.What about the Mod Hose4 told?
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One question. Is noise present during normal operation of the amp or during power off only? If power off only don't worry about it. Because of the lower voltage on a180 smps's the mod is implemented on series modules which are the ones you already have. You should be fine.
 
T

taccodude

Member
Joined 2006
Just tried different Wires for Speaker and Interlink,no differnece,even when I unhook the Source ,the Noise from the Tweeter is there.Then I changed to conventionell PSU (60V) and the Noise is gone. Is there something wrong with SMPS or can I try something else ? If SMPS is not ok ,that would be second Time ,Hypex is too expensive for that.
 
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