Need help building Ibanez Tube screamer.

[Izzy]

I just want to make sure whether the orientation of transistor is right or wrong on the stripboard layout that I made.


Stripboard layout:
http://img150.imageshack.us/img150/7219/tubescreamernb6.jpg


Schematics:
http://www.tonepad.com/getFile.asp?id=81

[MikeH]

If you go here:

http://www.datasheetarchive.com/

you can lookup the datasheet for just about any electrical component you can find.  Once you find the datasheet, lookup the pinout of the transistor you're using and check it against the schematic.  Make sure each pin (drain, gate, source, or collector, emmiter and base) is connected to everything it's supposed to be, and that will tell you if your orientation is correct.

[Izzy]

Ignore my stupidity, but I couldnt find the orientation of the transistor on the site you mentioned above.

but looks like its the other way around. 

[Izzy]

Finally I finished My Ibanez TS-9 / TS 808 (switchable) today!

It worked!

BUT why so less gain/distortion? IS orignal pedal like this?(I have never played TS9)
It was just like very subtle overdrive! Distortion wasnt even closer to MXR dist+.
Can anyone tell is thats what I am supposed to expect?


Then I tried adding another 4.7k resistor parallel to the 4.7 k resistor(to lower the resistance) which was going out from feedback loop. But the increment in gain was veryyyyy less, almost unnoticable. Itsnt that supposed to increase gain/distortion twice as much as before?


And one more thing,  I tried putting 100uf caps from +9ve to the ground to reduce 60hz. But instead that increased the hum slighly??

[MikeH]

Yes that's what a tube screamer sounds like.  It's a smooth low gain overdrive.  Think Stevie Ray Vaugn tone.  He used a TS808.  As far as the gain, try lots of different values of resistors; sometimes it takes a drastic change in value to produce a sublte change in output.

[GibsonGM]

That's what I was talking about, Izzy...why I like the MXR so much ;o)  They really don't come much more distorted than the MXR - what makes pedals different tends to be the diodes, input/output caps and if you add a tone stack or possibly another gain stage to them!  I don't care for the Tube Screamers myself, but they have interesting parts you can use in other pedals (such as the clipping section as a gain boost).

Perhaps playing with the resistor values can increase gain for you?

[Izzy]

Hmm ok. I was intrested in making this pedal because steve vai used to use it quite a few times, sometimes substituting for DS-1. SO I thought there would be enough gain!

I am still waiting for  toggle switch to arrive , once it arrives here, I will show you guys the picture! haha

In mean while I think I should experiment with resistors..hehe

[GibsonGM]

You can often get 10 pedals for the price of 1, lol...I think you can't beat the MXR for mod-ability...I can make that baby sound like a Big Muff, or a Super Metal Pedal, or Tony Iommi's dark sound.  Vai used so much processing in the studio it's hard to figure out just WHAT was going on there!  Octave/harmonizer units, etc     Probably used his OD stuff for cleaner passages, and went to something heavy for the whammy bar swoops.    It's all in the caps and tone stacks, my man!  Can't hurt to build things and have them if you want them later, tho...

[petemoore]

  It's supposed to sound like...of course an "Old tube amp...arent' they all...
  It's not as hard clipping as many Fuzzes, certianly not as clipping as a DIST+ or diode to ground type clipper.
  'Mild' clipping boosting overdrive sound...
  A boosting circuit in front of the TS can increase input source voltage = hits the diode threshold sooner/harder = harder clipping sound.
  Real nice for 'intermediate' clipping and boost...not clean, not hyper-distortey, good for lots of 'stuff'.

[Izzy]

Thank you GibsonGM and Petemore, Helpfull as always!

I did made few changes, I added turbo mode  .
When turbo mode is on it will engagae 2 more 4148 diode shunt to ground before the volume pot , and it changed 4.7k resistor and .047 uf caps after the feedback loop to 2.2k and .01uf. It helped to add lil more gain and fuzz. Just a lil though hard to notice.

Anymore suggestion will be appreciated!

[ubersam]

Change the 2.2K to a 1K, and the .01uf to .33uf = more gain and bassier

[Izzy]

Finally I finished my pedal today. But there is still some hum. noise? How t get rid of it?
.Its there even when I put my guitar volume knob to 0. But when I turn off my pedal its gone.I checked with pattery its still there.
Any idea?

[fixr1984]

Are all your wires still that long now that its installed in the box?
Sometimes having extra long wires will give you problems.
I usually install all the pots, jacks, etc first and then trim the wires down
so they are just long enough to reach and to give a little room if i need to remove that
part.

[Izzy]

Yes they are still that long.  They might look long but when when I tried to box it, it was kinda short 

[Izzy]

I used Audio probe and put guitar volume at 0. Then probed it from input. And it seems the small hum/noise comes after opamps output. JRC4885.
Could this noise be because of this so called "Noisy opamp" ?

HELP!

[MikeH]

From the picture it looks like your layout is still very big.  Lot's of exposed leads will create extra hum.  Also, make the wires from your input and output as short as possible.  They look to be about 6 or 8 inches long in the photo, that's too long.  If that doesn't solve the problem get some shielded wire and use that for your input and output.  The core is the lead, and the shield gets connected to the ground.  If you can't find shielded cable try twisting 2 wires together, using one as your lead the other connected to ground.  That might help a bit, but probably not much.

[Izzy]

No the wires arent 6" - 8" even it might look like that in the picture. I guess  normally they are 5". And  can you please show me where are the exposed leads at? If you are talking about that resistor in the switch I have covered them with an insulating tape.

Do you think the if I covered all pots and switches  terminals with insulating wire will that help a bit?
Its not a big hum/noise. Its little. But still I wanetd to get rid of it. I think its possible to make  a quiet pedal as commercial pedal isnt it?

Any help?

[MikeH]

What I mean is, on the back side of your vero, not shown in the pic, if you have components stretched out with their leads exposed, it will create extra noise.  Like if a component is stretched across more than a few traces.  If you have several doing this, it will be worse.  For you input and output, you have to look at the total length; the length from the jack to the switch, then from the switch to the board.  Your pic looks to be about 4-5 inches from jack to switch, then another 4 or so to the board.  Making these as short as physically possible will make the pedal more quiet.  Shielding them may also help.  I don't know about the pots.  I built a TS, using as compact a layout as possible, with the shortest leads I could use, and it's dead-quiet.

Basically, smaller design=less noise.  Components act like antennae that pick up unwanted frequencies.  Insulating them with tape or rubber won't decrease the noise, but shielding them might.

[Izzy]

Thanks sir. I appreciate your help. As far as I am concered I havent streched out leads on the other side, beside those caps which might be 2-3 mm above the board.
But what makes me suspious about the terminala at the pot is  the pedal is dead quite untill it reaches inputs of opamp and when i probe at the output then the hum/noise starts. The output of the opamp node also has drive pot connection. So I was guessing about that.

Can you give me some Idea how to shield? Does it has be to shield just with the input and output wire or for all the pots and switches?
And how do you make shortest wire possible? Even with this wire length I had hard time placing it inside box and reaching the switches and pot holes .

[MikeH]

Well there's no noise until after the amplifier, because that's where the noise gets amplified  .  If you cant shorten any of your wires, you'll probably just have to live with it.  If you want to try and shield your input and output leads, get some shielded cable.  Like guitar cable only a lot smaller.  It has an inner-wire that you use just like you're using regular wire for your ins and outs, then an insulator, then it's surrounded by a bundle of wires, or sometimes a mesh, that will be connected to the ground, and then it's insulated again.  idealy you connect one side of the ground mesh to the jack ground and the other to te ground at your switch or circuit board or wherever.  It's essentially the same as it is now only the ground going to your jack is surrounding the lead, just like in a guitar cable.  And as I said before, you can also try just twisting these wires around each other.  That will sometimes decrease the noise, but it's not as effective.