Orange Squeezer--jrc 4558 question about thread

[jimbob]

I was recently looking over A thread about orange squeezer dist..Im having the same problm and believe i can do the same as Saxim did. It was said that u should ground 1/2 the op amp- pins 5-6-7..  It looks as though pins 3 and 4 allready go to ground..Im using the GGG layout and rts pcb.

Simple question..Does this mean solder these pins( 5,6,7) togather and than to than solder to the ground?

[saxtim]

I didn't use the GGG layout, I used my own.  The orange squeezer uses only half of the 4558 (which is a dual opamp) Looking at the layout there, they used the other half of the opamp (pins 5, 6 and 7) than I did (I used pins 1 2 and 3).  The inactive part of the opamp on that layout is pins 1,2 and 3.  That layout alread has pin 3 tied to ground and pins 1 and 2 tied together making the unity gain follower that I had to set up.  Are you experiencing distortion?  There may be some other problem.  I found that there was really only a small amount of area on the trimpot that I could get a useable signal out of that wasn't distorted.  This happened to be up around the highest compression level though, which suited me.  What symptoms do you have?

Btw, the answer I give above is pieced together with my limited electronics knowledge- you might want someone with more experience to confirm what I've said.

tim

[jimbob]

Im very limited as well..What else did you try  in terms of knocking out some dist that actually made a difference..Did u change the values of output caps ect..that made a diff. Or was it mostly the trimmer knocked back that made any real diff?

Thanks.

jim

[smoguzbenjamin]

Couldn't you use a TL071 (single opamp) or equivalent for the squeezer? It seems a waste to have a dual opamp sitting there with one half doing nothing....

[Mark Hammer]

Look at the mods for the OS that JD posted on GGG.  I whipped up one that uses the other half of a dual op-amp as a tone/gain recovery stage and I was very pleased with the result.  Allows you to use a gain control on the first stage to reduce compression without having to sacrifice overall level.