Print Page - equal and vbias problem

Title: equal and vbias problem
Post by: benfox on January 02, 2009, 08:01:52 PM

hi,

I've a problem with this beast i got no sound or very distorted sound :
http://www.aronnelson.com/gallery/main.php/v/STMs-Circuit-Ideas/Three_band_Eq_non_interacting_bands.png.html

I know the bias is 1/2 of the supply. I design my board with a voltage divider and i get 4.5V on pins 3 5 10 on my tl074.

I've plug my input as V1 on the schematic. Is it right ? i'm not shure of it. The input needs Vbias ? (I've tried nothing changed)
Did i miss something ?
This project seems cool. I'd like to make it work.

Thanx

Title: Re: equal and vbias problem
Post by: oskar on January 03, 2009, 12:45:33 AM

You would need cap's on the in and output.
Audioprobe it. What do you get at the output of X7?

Title: Re: equal and vbias problem
Post by: benfox on January 03, 2009, 06:02:05 AM

I've tried what you guess but still no sound.
Any other idea ?

Title: Re: equal and vbias problem
Post by: shadowmaster on January 03, 2009, 06:03:24 AM

Check out http://www.runoffgroove.com/tonemender.html (http://www.runoffgroove.com/tonemender.html)

Copy the input and output stage of the circuit then insert the eq circuit fragment in between.

Title: Re: equal and vbias problem
Post by: benfox on January 03, 2009, 07:40:03 AM

Thanks.
I've finally debugg the beast.
I'm ashamed of my mistake...
I had inverted input and output between the bass and the mid stage and between the mid and treble stage.
The circuit works quite well. Maybe i could be interesting to tweek the values of cap in the mid stage or to add another mid stage with the 4th opamp part.

Thanks again !!
Happy new year !!

DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: benfox on January 02, 2009, 08:01:52 PM