YATS Overdrive (CJOD Lite)

Mr. G. · Post by **Mr. G.** » 09 Nov 2008, 02:43

Closest pot I have to that is a B5K. How would that work, and how would it effect the overall tone?

Also, I've been wanting to try using a Baxandall EQ in one of my pedals, and was thinking this one would be a good candidate. What do ya'll think about that? Are there any perf or vero layouts of a Baxandall or maybe something that incorporates one? Would it be better to use the passive James version that's in the Tone Stack Calculator, or use half of the opamp for an active Baxandall?

kurtlives · Post by **kurtlives** » 09 Nov 2008, 04:30

5K should give you decent results. You could take a common 4K7 resistor and put it in parallel with your pot to get it closer to 2K.

kurtlives · Post by **kurtlives** » 09 Nov 2008, 04:34

Mr. G. wrote:I just built this pedal, and am loving it so far. I think I might have a slight problem though. The tone control isn't super noticeable between 7:00 and 4:00 (it does have an effect, but it's not a big one), and then once you pass 4:00 it jumps to being really bright with no real in between. Any idea what could be causing this?

The only thing I did different was that I built it on vero board rather than perf. It only needed some very slight adjustments. Here's the layout I made: YATS vero
The blue "jumper lines" of D1 and C6 actually represent their leads under the board. J18 is the input, A1 is the +9v, B1 is Ground, and Level 2 is the output. There are hard to see trace cuts under R7, C8, C7, and R5. Hopefully there aren't any errors in my layout that are causing the tone control to act like it is.

Regarding that D1 "jumper"....

Why not just out that bypass cap in the space of vero between the two clippers?

With C6 I would just put a jumper between H and I.

Mr. G. · Post by **Mr. G.** » 09 Nov 2008, 13:56

I see what you're saying about C6. It would have made the layout look cleaner, but when I built it, it was just as easy to bend the bottom lead up to the H strip.

Are you talking about moving C4 to between the LEDs? If I did that how would I connect it to pins 6 & 7 of the IC? It probably could have been done with actual jumpers, rather than bending the leads, by making the board a little wider.

Also, to put the resistor in parallel with the pot, would I connect across lugs 1 & 3?

Mr. G. · Post by **Mr. G.** » 10 Nov 2008, 22:11

Got another question... What would I need to change if I wanted to lower the mids a little, and possibly not roll off quite so much lows, but mainly I want to know how to adjust the amount of mids.

briggs · Post by **briggs** » 11 Nov 2008, 13:22

You would lower the point of bass roll off by adjusting the cap that goes to bias on the first opamp stage. Increase the cap to lower the point of bass rolloff. TO reduce the mid hump you could look to adjust the response of the tone control section, check out the technology of the tube screamer article at geofex.com, it's a great article and will basically allow you to custom tailor your Tubescreamer to your ultimate choice

paulc · Post by **paulc** » 11 Nov 2008, 15:46

If you want to lower the value of the tone pot you might instead want to scale the values of the other resistors and caps in that circuit. This will give similar results without having to hunt for pots.

Opamps have a pretty low output imp, but not that low. The standard 1k/.22uf filter coming off of it will load it down some. If you look at it on a scope with it cranked you'll see a "kink" in the output of the op. This may or may not be something you like about the tone. Scaling the resistors up will reduce the loading on the opamp

Try scaling the values by a factor of 10 . Change the two 1kohm to 10k, and the 220ohm to 2k2. Change the two .22uf to 22nf. This would be sort of close to a stock circuit with a 2k pot, but with no loading on the opamp.

Also about that tone control... At the darkest setting it parallels with the .22uf preset filter. You can set this up to act a little bit more like a 2nd order filter by putting a little isolation between the two caps. If you scale up by 10 try splitting the 10k in half, and put the 1st cap in the middle (scaled of course).

There's a ton of things to do in this area.

Later, PaulC

Mr. G. · Post by **Mr. G.** » 11 Nov 2008, 16:41

Thanks a lot guys! This definitely gives me something to work with.

Mr. G. · Post by **Mr. G.** » 18 Nov 2008, 02:16

Here are the changes I made...

R7 to 10K
C6 to .022uF
R9 to 2K2
C7 to .022uF

This smoothed out the tone control very nicely. However, when the tone is maxed, it sounds fairly muffled, and there's not much sparkle.

So, I'm now thinking about making the following changes...

R7 to 10K
C6 to .01uF
R9 to 1.2K
C7 to .047uF

What are your thoughts on those values? Also, would it be worth it to play with the values of R5 and C5? If so, should I scale them like the other RC's, or...?

Mr. G. · Post by **Mr. G.** » 18 Nov 2008, 20:25

I made those 4 changes, and also changed C4 to a 100pF silver mica cap (just because I had an extra one). These changes really brought the pedal back to life!

paulc · Post by **paulc** » 19 Nov 2008, 04:34

Mr. G. wrote:Here are the changes I made...

R7 to 10K
C6 to .022uF
R9 to 2K2
C7 to .022uF

This smoothed out the tone control very nicely. However, when the tone is maxed, it sounds fairly muffled, and there's not much sparkle.

Don't forget R8. You need to also scale R8 to 10k like you did for R7.

BUT... R8 along with R9 sets how much gain the EQ stage has when on 10. If you find that it's to bright at the max setting start bringing R8 down in value. You don't want to bring R9 up to reduce gain because that will decrease the max amount of cut in the control.

Also it doesn't have to be scaled by 10. That was just to keep it close to the range of the 2k pots that were talked about in this thread. You might like something inbetween.

Later, PaulC

Mr. G. · Post by **Mr. G.** » 19 Nov 2008, 10:47

D'oh

I completely overlooked changing R8. I'll report back once I get that done.

Mr. G. · Post by **Mr. G.** » 19 Nov 2008, 21:57

OK, I changed R8 to 10K and that really brightened it up and gave the tone control a much wider range. I might even have to lower it a little.

Thanks again for all the help!

danielzink · Post by **danielzink** » 22 Nov 2008, 04:10

Mr. G. wrote:OK, I changed R8 to 10K and that really brightened it up and gave the tone control a much wider range. I might even have to lower it a little.

Thanks again for all the help!

Have you had a chance to back R8 down in value yet ?

What are your impressions from the changes you've made ?

Thanks, Dan

Mr. G. · Post by **Mr. G.** » 22 Nov 2008, 15:46

No, I haven't got around to it yet. I'll be sure to let you know how it works out as soon as I do, though.

Mr. G. · Post by **Mr. G.** » 24 Nov 2008, 02:26

I just changed R8 to a 5K1, and I believe that's where I'm going to keep it.

So far, this is my favorite pedal that I've built. I think I might even build a second one, so I can have one set with the gain up, and one set with low gain. The changes I made didn't really change the sound or feel of the pedal, they just made the tone control more usable. For such a simple pedal, it's pretty versatile. Not necessarily in it's tonal range, but in it's gain range.

danielzink · Post by **danielzink** » 24 Nov 2008, 06:12

Thanks for the update !

Dan

nooneknows · Post by **nooneknows** » 17 Jan 2009, 23:22

Hi,
I built the YATS some ago with only two differences from the original: the opamp was a 4558, because I was not able to find a opa2134, and the tone was a 10K resistor in series with a 10K linear pot (to cure the absence of a 20k W taper).
Today I received some opa2134: I have to say the difference is... huge! it sounds wonderful compared with the old one, I've never thought I could hear such a difference!
Obviously the pedal went directly to my pedalboard as my new 'official' overdrive!

edit: wrong, I forgot it, there is another difference from the original, I used asym biasing 10K + 12K

beedotman · Post by **beedotman** » 10 Jun 2012, 16:02

Here is layout for CJOD lite:
viewtopic.php?f=13&t=17923