Problem with Mini3 :( - Page 4

Quote:

Originally Posted by ShinyFalcon 

How about V+ and IG? Is it equal to V- and IG?

Sorry for answering so late... V- and IG measures 4.98V and V+, IG = 2.8V. I've got a wallwart and replaced the fuse of my DMM.  Quiescent current test and charger ciruit test are OK.

Anyways I've plugged my headphones to the amp to see what happens, but sadly it does not work ok: when I set the volume dial to its almost minimum position the amplifier works fine  . then I've increased volume to 12 o'clock and after a few minutes it begins to sound hollow for a few seconds and finally the sound fades out completely and abruptly. The more I increase the volume the sooner the amp stops working.  Then I switch the amp off, turn it on afterwards and once again the amp works normally for a brief period. That the amp is connected to the AC-DC adapter  or not is indifferent, it follows the same behaviour in both cases. Probably this makes no sense, but may be that the power  super-bright LED draws too much current or something?

sorry for bumping old thread, but i got this one question..

i'm planning to build 3 channel amp quite similar to mini3, but i don't know where to connect the input ground to. the output pin jack is definitely connected to the ground channel, right? so where should i connect the input ground?

this is the schematic of the ground channel:

looking forward for some inputs from you guys..

The input ground is the symbol just to the left of R1G.

Quote:

Originally Posted by Avro_Arrow 

The input ground is the symbol just to the left of R1G.

i see..i thought that ground is supposed to be connected to V- below C5.. CMIIW

so the opamp U4 receives 2 input from TLE2426 and input signal?

then the input ground should just be connected to the left of R1G and that's it? done?

Not exactly.

The TLE2426 creates the virtual ground that is used by all components

except the output ground. The op amp provides the output ground which needs

to be isolated from the other grounds.

Quote:

Originally Posted by Avro_Arrow 

Not exactly.

 

The TLE2426 creates the virtual ground that is used by all components

except the output ground. The op amp provides the output ground which needs

to be isolated from the other grounds.

hmm..i understand some of your answers, but not completely..

if the output ground must be isolated from other ground and connected directly to output ground socket, where should i connect all the grounds from right and left channel in mini3 schematic?

btw, thanx for the quick response!

This article from Tangent may be of some help to you...

If you still are having problems afterward I will help you some more.

Quote:

Originally Posted by Avro_Arrow 

This article from Tangent may be of some help to you...

If you still are having problems afterward I will help you some more.

okay, i'll do some reading first. thanks again!