Problem with high DC on speaker terminals

[Phear]

HI!
I finished my CG with LM3886 late last night. Joy!? Well, no. I went on measuring DC on the speaker terminals. Eek! 33V. Obviuosly I have done something wrong. I was to tired to start checking for errors last night so that became today's problem. I thought maybe you guys can give me some hints about what errors to look for...

The chipamp i've built is the one found at Linkwitzlab.com

cheers/Per

 

[Mad_K]

Is it dc on either +/- input?

 

[SY]

Do a quick voltage map- start by measuring DC voltage on each pin. 9 times out of 10, that will quickly lead you to where the error is.

 

[Nuuk]

Sounds like one rail is down, or not connected to the chip.

 

[GregGC]

HI!
I finished my CG with LM3886 late last night. Joy!? Well, no. I went on measuring DC on the speaker terminals. Eek! 33V. Obviuosly I have done something wrong. I was to tired to start checking for errors last night so that became today's problem. I thought maybe you guys can give me some hints about what errors to look for...

The chipamp i've built is the one found at Linkwitzlab.com

cheers/Per

The speacker is connected to 0V rail and the rest of the GNDs are connected to GND simbol. The speacker should be connected also to the GND symbol and the GND symbol should be connected to 0V reail directly. The 2Ohm res is between GND/0V and Chassie.
The way you have it your decapling caps have 2 ohms res in ser with the speaker. Not good IMHO

 

[Phear]

I forgot to mention that i don't use Ro & Ci

I found out what was wrong! It aparently slipped my mind to connect the signal ground to the powerground.

thanks anyways guys!

I haven't listened to it yet so ti remains to see if if I have to re-wire the whole damn thing due to the sweet sound of motorboats.
Here's a pic of my amp:

An externally hosted image should be here but it was not working when we last tested it.