Tube Screamer parts question

[jimbob]

the parts list  requires a  51pf--on a seperate website the info says you can use a  4.7 uf 16v--either or..is this true..its easier for me to find a 4.7 but which way would you orient an electro cap v/s a tantalum?--im making the TS-808 from GGG web ste..

[brett]

What the...?  You're not talking about replacing the 51pF with a 4.7uF are you?

The 51pF cap is there to let high frequency stuff thru.  Any cap from 33pF to 100pF will be ok, but a 47pF will be closest to the original.  You should be able to get a little ceramic 47pF cap from most shops.  Some will also have polystyrene caps, which some folk like better.

The only place for substituting a 4.7uF 16V in the GGG TS-808 clone is for the 10uF output cap (where it would do a fine job).  The negative side of the cap goes to the output.

The only tantalums in the project are 2 x 0.22uF.  They can be replaced by greencaps or MKT caps if desired.  Some folk say that the tantalums "add" something to the sound ("grit"?), but it's also normal to imagine that something's different when you know you've changed something.

Hope this helps somehow.

[jimbob]

it really does help.. i was thinking about putting a 33  or 47 pf there since i have some...btw..what do you think about the mod for adding gain= changing the 4k7 /.047uf attached to pin 2  of the  opamp to 2k4 / .1 uf and changing the 51pf to 22pf for doubling gain w out chnging the freq response? ever heard of this or tried it?

[brett]

it really does help..

Great!

i was thinking about putting a 33 or 47 pf there since i have some...

That's ok

Re:btw..what do you think about the mod for adding gain= changing the 4k7 /.047uf attached to pin 2 of the opamp to 2k4 / .1 uf

Personally, my TS9 has two switches to make these mods, and I find that I always have it set to use the 4k7 resistor and the 0.1uF cap.  I really like the extra "guts" you get with the 0.1uF cap.  You can get the extra gain that the 2k4 gives by simply turning up the drive control some more (but IF you have it at max most of then time :twisted: , THEN it's probably a useful mod for you)

and changing the 51pf to 22pf for doubling gain w out chnging the freq response? ever heard of this or tried it?

The 22pF cap won't change the gain at all.  Leave it at 47pF.  It works at radio frequencies (MHz and up).

Lastly, I recommend socketing the IC and trying some different ones.  The XX4558 isn't the world's greatest chip.  Although many people don't like the TL072, I don't think it's that BAD, either.  My personal favourite (and some others' favourite too) is the NE5532 (definately quieter than the others and with less harsh distortion).  But these things are a matter of taste - some people just love that "gritty" distortion of various 4558s. (PS I did my tests of different chips "blind", so that I didn't have any pre-conceptions of the sound.  The worst chip in my chip shoot-out was the JRC4558 - which is the "classic" TS chip :shock: )

[jimbob]

thanks Brett, I appreciate your time to respond...

[Ansil]

i like the cmos chips...  vary nice...