supply rail voltage on 3875 output ?

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Hello
Having assembled my god knows what number gainclone, I find it to behave strange - that is I have 25 volts on the output og leg no.3 - I have double, triple and quadruple checked everything.
Both channels behave this way.
Any suggestions ?- blown chips ? anything ?

Cheers !
Buhl - who's getting more grey hair than I should.....
 
Buhl, I have also got quite a few successfully completed GC's under my belt but I started making a paralelled LM3875 and found that I had 25 volts on the output (37 volt rails). I separated both sections and found that they also both have 25 votls on the output.

I have been over this amp I don't know how many times and cannot find anything wrong so I too would welcome any suggestions! :xeye:
 
Yehaa !
Thanx for helping me turn the magnifying glass in the rigth direction - I had looked only at the amp board again and again, and found no errors, turns out I had forgot to attact signal ground to star ground with a lead from the volume pot, hence no resistor from signal input to ground....works like a charm now !

By the way, the Elna Cerafine caps i use in the PSU(1000uF/25V) is a lot better than the "standard" panasonic FC caps to my ears - with the pana caps the highs got a little sharp og edgy, now they are detailed and not straining to listen to - well worth their relativly low price I think.

Thank you!

Cheers !
Hans
 
That can be understood in two ways I think - I think of it as the voltage of the positive supply, that is between + and 0 - but the negative side will have the same value (should have).
So when I say 25 volts, you "could" say that the total supply is 50 volts(measured over + and -), but I think that most people will say that a 25-0-25 volt DC supply is a 25 volt supply.


Cheers !
Hans
 
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