ChipAmp PSU Question

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korben69

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Joined 2006
I've finished building a LM1875 kit from BrianGT, works fine !
I've got a spare PSU board designed for LM3886, BrianGT design too.
Wondering if I could use this one for my LM1875 amps ?

My trouble is that there are +V/+PGND and -V/-PGND pins on the DC side.
PSU is tested and OK, about + & -26V DC with 2x18AC/160VA rated trafo.
Could I wire together -PGND and -PGND safely ?
IMHO yes, but your confirmation is awaited ;)
Regards
 

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korben69

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Joined 2006
Replaced the standard LM1875 ChipAmp PSU with the one designed for LM3886.
Works perfectly fine, seems to me that bass are more defined and deepest...
More listening is required before tweaking.
Thanks again for your input palstanturhin ;)

PS : BTW I've got a fully functional & tested LM1875 PSU for sale...
 
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korben69

Member
Joined 2006
Thank you Digits for the link, I've read the III parts, interesting and usefull ;)
Maybe a part of the answer is adding some filtering caps, 100uF before the existing 100nF (before RC 1R/100nF). Same thing, 100nF before rectifiers.
Don't know if it will solve "plop" when powering off the amp.
It seems to be caps "discharging", not hum or hiss, the amp is dead silent.
I've to test DC offset too.
Swapping source for a CDP gave the same result as USB/DAC...

PS : same "plop" using standard ChipAmp dedicated PSU for LM1875.
This one is only a single bridge, without snubber.
 
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