4.5v bias marshall blues breaker

[benfox]

hi guys ,
I've built an easy clone of Marshall blues breaker. I can't remember where i've found it but there is a problem. :oops:
It works only when i contact two point quickly and release them.
It works for a while and the sound die. I think it's a bias problem but i don't really know what it means !!! On the schematic the pin 5 and the pin 3 had to be connected to a point called 4.5v bias. When those points aren't connected it does nothing but when i touch just for a moment those points to pin 6 it work for a while. Strange.
Where should i connect those points :roll:

[petemoore]

Read what to do when it doesn't work.

[walters]

1.) if the Transistor is not bias then its not doing to work
         in its linear operations and it going to be a switch
         thats why it cuts off its either in cutoff mode
         its the nonconducting state of a transitor or the trim pot
         just shorted out the stage

                                                walters

[The Tone God]

The blues breaker uses opamps not transistors.

As stated earlier make use of the "What to do when it doesn't work" sticky and fill out the information for more help.

Andrew

[Mike Burgundy]

That said, it looks like you've missed a couple of connections that are on the schematic. Without those, the circuit won't work, or at least not as it should. Think about it: what would it do if you don't hook up one end of the battery?
Fill out the sticky, but also make damn sure your wiring matches the schematic (all of it) and is sound. Points with the same label and symbol (such as 4.5V bias or 9V, or ground) should be connected together. By the way, the 4.5V bias is made by a resistive devider (10k or 100k or something, two of them from 9V to ground. 4.5V is in between the two) and used for the correct biasing of opamps.

[benfox]

Sorry guys i had a bad schematic !!!
I find at last the one from GGG and it's OK now
:oops:  :oops:  :lol: