PROCO RAT question

[darkstar011]

I asked this on another forum but no luck, im hoping you knowledgeable folk will know the answer.

So my problem is this.... when i dig in hard on the guitar the signal kind of fades out quickly and back in again.. I suspect the opamp just can't cope with the strength of the signal and gives up for a brief moment.

1) would Biasing the opamp be the way to go?  (i don;t really know what this means, but i think theres a 1M resistor doing this?)
2) would there be another resistor / cap change ( i think the first is a 1k) to help protect the opamp from an overly strong signal.?

thanks ?   here is a link to a schematic http://diystompboxes.com/pedals/PCRAT1.GIF

[petemoore]

  Try new battery, test the bias voltages on the OA pins to ground.
   I had a Rat that 'ducked' a little...

[darkstar011]

ducking , thats a good way of putting it.   I hadnt considered the power supply, i run it on mains but i will try it without it daisy chained . thanks. 
i upped the 1k input to a 10k earlier im not quite sure what that did but it seems a tiny bit better.

[Joe Hart]

Darkstar011, I'm MUCH less knowledgeable then at least 90% of the folks here, but can you post the voltages of the pins of the opamp? I wouldn't know what to do with the information, but I'm sure many other may. At any rate, that's one of the things that people always ask for when trying to troubleshoot a problem. I'm suggesting this because I noticed that you have 2 posts. Welcome to the DIYstompboxes Forum!
-Joe Hart

[darkstar011]

im sorry i have no idea how to do that :-/ i dont have any equipment apart from a soldering iron . both my RATs do it though i know that

[darkstar011]

and thankyou very much btw

[stringsthings]

.... i dont have any equipment apart from a soldering iron ....

welcome to the world of DIY, darkstar ! .... and at this point, i ( and many others ) would recommend that you invest in a DMM ( digital multimeter ) .... they are available from many sources .... and at several price points to meet your budget ... ( expect to spend around $20+ ) .... and the RAT circuit is an excellent one to get voltage readings from - you simply connect the "ground" probe ( black ) to a ground point of the circuit ... and then you touch the "test" probe ( red ) to the point in the circuit where you want to read a voltage .... for example, if you test the red wire connection to the circuit board coming from the battey connector, you should see a reading around 9.0 volts on the meter ...

.... also, with a DMM, you can be more confident during the contstruction phase any project .... i like a meter with an audible continuity feature ... ( tests for good solder joints by "beeping" ) ...

( in the old days, we had to watch the meter's needle deflect towards one end of the scale ... oh, the humanity!  )

[darkstar011]

lol! ok :-)