Timmy build

[Kipper4]

Todays build was a Timmy.
Sweet little thing is'nt she.
obviously i made a couple of booboos in the process of building and i built the diode switching on a dpdt
I tried jrc4558s LM1458s and TL072
the jrc4558 works best for my ears and gear.
I also used 4148 clipping diodes the (mojo) yellow coloured ones.
Thanks to Paul Chromosphere.
Also i need to fix the bass cut yet. It isnt cutting Doh
It has a fair range of sounds but i'm not sure i have used it to its best advantage yet.
I need to check it with HB pups and a high gain amp next.
Anyone else built it and liked it?
Any tips?

[Kipper4]

heres the schematic i'm working from

http://revolutiondeux.blogspot.co.uk/2008/05/wanna-build-timmy-overdrive.html

can you see a problem with the bass cut because i'm certain i've built it as per schematic and it doesnt do sqaut.
substituted the 39nf for a 33nf
the treble cut goes to ground is this whats happened the bass needs to go to ground and not Vref?

[Mark Hammer]

If the gain control works, then you have the bass-cut section wired properly. 

One way to confirm this is to set the gain high, and then vary the bass-cut trimmer.  One a non-inverting op-amp, the gain is set by the ratio of [feedback-R + ground-leg R]/[ground-leg R].  So, if the feedback R is set low, the numerator and denominator are essentially the same, and you won't notice much difference, altering the bass-cut.  If you turn the feedback R up, however, the ground-leg R starts to make a bigger difference in the gain produced.

The bass-cut action is really a byproduct of providing more gain for the mids and highs than for the bottom.  Or conversely, the bass-boost is a byproduct of providing pretty much the same gain for the low end as for the rest of the signal.  The bass rolloff is given by the value of the cap (normally .047uf in a TS, but higher in a Timmy), and the ground-leg resistance, using the time-honoured F = 1 /[2*pi*R*C].  So, if the R and C, respectvely, are 10k and .33uf, then the rolloff in gain starts around 48hz.  Drop the 10k down to 5k, and the rolloff moves up to 96hz, and so on.

[Kipper4]

Yep I see where your coming from Mark although its still pretty subtle to my ears.
I have a copy of electrical engineering 101 now so hopefully i will be able to follow your calculus soon too.
thanks dude.
Rich

[nocentelli]

Yep I see where your coming from Mark although its still pretty subtle to my ears

The Timmy bass cut should not be subtle (and should connect to vref, not ground). With the gain at minimum, the pedal should give a completely flat boost with both treble and bass at minimum: Turning the bass cut up *should* audibly decrease the bass content, so much so that the Timmy can work well as a clean (or dirty) treble boost if you cut the bass right back and turn up the volume (and/or gain).

[Kipper4]

I might try another pot then incase because mines still subtle unlike the treble cut.

[Hemmel]

Funny, the schematic shows "Volume 10k" but the part list shows "LEVEL 100k". I'm guessing both will work ?

[nocentelli]

A10k for volume

[Pojo]

Both will work though...100K will allow a hotter signal to output.

[electrosonic]

The Timmy bass cut should not be subtle (and should connect to vref, not ground)

Why does the bass cut need to connect to Vref and not ground?


Andrew.

[Eric.nail]

that's a shitty layout...Just FYI.

If you're looking for Vero There's another out there by a specific fella who "rhymes with immark" haha!

I'v attempted that layout a few times and had NOOO luck...

[alexradium]

Timmy is THE most versatile soft clipping pedal out there,it has the biggest range of tonal controls and drive.
For sure you did some mistake.
For vero boards go here http://tagboardeffects.blogspot.it/

[samhay]

The Timmy bass cut should not be subtle (and should connect to vref, not ground)

Why does the bass cut need to connect to Vref and not ground?

If the schematic here is correct, then it doesn't have to go to Vref - ground will work fine too.

http://revolutiondeux.blogspot.co.uk/2008/05/wanna-build-timmy-overdrive.html

[nocentelli]

The linked schem works as drawn as far as I know.

Weirdly, I tried bass control to ground in an effort to avoid worrying about orientation when using an electrolytic cap for the 1uF, and I couldn't get it to work on the breadboard (this could of course be an error on my part) so I'd be glad to hear of someone else getting it to work.

[Kipper4]

Me too.
I havent tried a differant pot yet. I did check the pot was working as expected with DMM)