SA2015 V-MOSFET Builders

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thimios

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Joined 2009
astx said:
same result when only one channel connected?
The amplifier pcb is isolated mounted on the heat spreader? The first prototype pcbs have the screw fields erroneously unisolated ...
Click to expand...
Yes,same.
115mV for the CONNECTED channel ,7mV when laptop mute.
70uv for the DISCONNECTED channel.
I have isolate the mounting holes on the bottom using a dremel.
 
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astx

astx

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Joined 2011
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You have said you can hear nearly no noise with the ear on the speaker. maybe you measure some dac artefacts. laptop soundcards often have bad output filters and your amp has a very high power bandwidth.
use your scope to check the output signal frequency and amplitude.
 
T

thimios

Member
Joined 2009
astx said:
You have said you can hear nearly no noise with the ear on the speaker. maybe you measure some dac artefacts. laptop soundcards often have bad output filters and your amp has a very high power bandwidth.
use your scope to check the output signal frequency and amplitude.
Click to expand...
Yes, i must put my ear in contact with the tweeter to be able to hear a very low level noise.
I tried to pull the jack and short this using an aluminium paper, the measurement is 0 mV.
The cable is like this but 1.5m
 

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astx

astx

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Dear Thimios,

looks pretty good! :):up::up::up:

I would do one change: the small signal lines (ribbon cables) route above in the middle of the amplifier. The sharp edges from the steel bottom may destroy the cables.
The signal cables carry only constant DC and speaker output signals decoupled by 4.7k (for DC detection).

BR, Toni
 
T

thimios

Member
Joined 2009
astx said:
Dear Thimios,

looks pretty good! :):up::up::up:

I would do one change: the small signal lines (ribbon cables) route above in the middle of the amplifier. The sharp edges from the steel bottom may destroy the cables.
The signal cables carry only constant DC and speaker output signals decoupled by 4.7k (for DC detection).

BR, Toni
Click to expand...
Dear Toni,don't worry!:)
I will take care in the finally assembled amplifier.
I will enclose this ribbon cable (at these <<dangerous>> points) in a thermal shrinking tube.;)
Thanks a million!
Thimios
 
astx

astx

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I have placed the feets without mounting under the amp and moved them around for best optic. measured the distance and afterwards checked, if the screws doesn't touch anything inside the amp.

I can send you my cad file from latest amp...

BR, Toni
 
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