"more treble" mod for my OD1?

[Xavier]

OK, here's an unusual request.

My OD1, built as per Kojjum's vero layout, is working, and sounds exactly like my Boss OD1. I have raised the input cap to 68nF for some more bass (0,1uF makes it a little bassy sounding for my taste).

The question is, there's not any cap around the diodes, and I'm wondering is there's anything I can do to make it actually brighter. The SWTC is a passive circuit and it only lowers the high frequencies.

Any magic cap or resistor change to achieve this? I've been searching through the old posts and I haven't found such a mod...

[wampcat1]

I don't believe there is any one component in that circuit that will add MORE treble (going from memory, I don't have the schem in front of me), but you can always increase the resistor that is connected to that .068uf cap (that controls bass) and get more gain and also some more treble. Alternatively you could always add a quick lpb-1 type circuit at the end and throw in a tonestack of some sort (maybe a fender or vox?)

Hope that helps!

Take care,
Brian

[Xavier]

I don't believe there is any one component in that circuit that will add MORE treble (going from memory, I don't have the schem in front of me), but you can always increase the resistor that is connected to that .068uf cap (that controls bass) and get more gain and also some more treble. Alternatively you could always add a quick lpb-1 type circuit at the end and throw in a tonestack of some sort (maybe a fender or vox?)

Hope that helps!

Take care,
Brian

I was afraid of that.....What I see in the layout after the aforementioned cap (the input cap) is a 1K resistor that goes to the base of Q1. I have never seen any mod that refers to this component. What value would you suggest? 2K?

[MartyMart]

I would reduce that cap at the front end, which you've made bigger  !!
Try a 22n or 33n
"More bass" means you hear "Less treble"
If you "turn up" bass/mid/treble that's just a "volume" increase ... see ?

Marty.

[Arn C.]

What about the 1uf cap on the output?  Did you try changing that for a difference in treble?
Just a thought......

Peace!
Arn C.

[Xavier]

I would reduce that cap at the front end, which you've made bigger  !!
Try a 22n or 33n
"More bass" means you hear "Less treble"
If you "turn up" bass/mid/treble that's just a "volume" increase ... see ?

Marty.

I've made the same guess right after changing the cap. But in my ears the pedal eq is something like bass-3, mids-8, treble-5. AFter the change I have bass-6, mids-8 , treble-5. I knew this was going to happen and that's why I didn't go for the 0.1uF, which would have been definitely too much.

Maybe I put an SPST so I can choose between both.

[Xavier]

What about the 1uf cap on the output?  Did you try changing that for a difference in treble?
Just a thought......

Peace!
Arn C.

Didn't think about it. Will try it tomorrow by lowering the value...thanks.,

[Steben]

This is a stock pregain EQ and postgain EQ discussion. Ideal would be an EQ in front of the pedal and another one after the pedal... you know what I mean. The problem with cap values is that when you use smaller output caps the first thing you'll hear is loss of bass. Little change in cap value brings firstly a big change in bass, not in treble.

Usually a small input cap and a large output cap is used, so you get sweet distortion (trebel boost) and full output. A bass boost after the stock pedal is always better. If you use a treble cut instead it brings eventually mid boost as effect. Typical disease of lots of OD pedals. A Big Muff tone control can solve the problem.

[wampcat1]

I don't believe there is any one component in that circuit that will add MORE treble (going from memory, I don't have the schem in front of me), but you can always increase the resistor that is connected to that .068uf cap (that controls bass) and get more gain and also some more treble. Alternatively you could always add a quick lpb-1 type circuit at the end and throw in a tonestack of some sort (maybe a fender or vox?)

Hope that helps!

Take care,
Brian

I was afraid of that.....What I see in the layout after the aforementioned cap (the input cap) is a 1K resistor that goes to the base of Q1. I have never seen any mod that refers to this component. What value would you suggest? 2K?

Sorry, I misread - I didn't realize you had increased the input cap, I thought you increased the .047 cap off of the gain section (http://www.freeinfosociety.com/electronics/schematics/audio/pictures/bossod1.png ), and I was referring to the resistor it connects to. This is the cap that most people change if they want more bottom end (It IS pre-clipping, though, so I wouldn't go crazy). Another poster recommended the big muff tonestack, that would be an excellent choice IMO.

Hope that helps!

Brian

[lenwood]

The big muff tone control would be best, as Steben has said.

Another thing you can try is to add a treble bleed capacitor on the
volume (output) pot . This will let more treble thru when the
volume is turned down.

search for treble bleed

[wampcat1]

I would reduce that cap at the front end, which you've made bigger  !!
Try a 22n or 33n
"More bass" means you hear "Less treble"
If you "turn up" bass/mid/treble that's just a "volume" increase ... see ?

Marty.

That's a good point, Marty, and one that confuses alot of the new DIY'ers. More often than not, a given modification is not going to ADD more bass/mids/treble/etc to a signal, you are just changing the qualities of component (or group of components) that is filtering out this frequency. For example, if a person is modifying a pedal and wants more bass on the tail end of the circuit, you want to filter out the mids and highs and allow the lows to pass through more. Of course, you may have to add an additional stage after there to boost the volume (signal) back up. For Xavier's purpose, he wants to lower the mids and lows yet allow the highs to pass through. This can be accomplished through a series of rc filters, but probably quicker and easier to use a big muff tonestack (as noted above). I myself have alot of smaller prebuilt circuits so that if I want to see what happens when you boost the signal before the tonestack versus after it, I can throw a couple of jacks on the breadboard and insert one of these little prebuilt circuits. Andy Carroll (dragonflyfx) does this quite a bit I believe and is the person who really got me thinking as to how handy it is to be able to experiment quickly without doing alot of breadboard rearranging.

Anyway, sorry about going so OT...i guess it's time to take an A.D.H.D pill! 

Brian

[Xavier]

You guys are so helpful, really.

OK BMP tone control then, or after reading Jack's article on it , it will be the AMZ tone control, mainly because the BMP seems to cut highs even more, and that's the opposite of what I want.

OK so now the next two last questions would be:

- This is a passive tone control? the OD1 seems to have enough output not to need a gain recovery stage.

- Where in the OD1 circuit do I insert this tone control?

Again, thanks for all your help. You guys are the ones to blame . I'm selling most of my pedals and subbing them with my DIY mongrels

[Xavier]

The big muff tone control would be best, as Steben has said.

Another thing you can try is to add a treble bleed capacitor on the
volume (output) pot . This will let more treble thru when the
volume is turned down.

search for treble bleed

That sounds smart, as I don't use the OD1 as a booster but as a stand-alone drive pedal, and usually the output knob rarely reaches "2:00"

[Xavier]

UPDATE ON MY OD1.

I said it sounded too dark, no wonder it did. Both lack of attention and patience are no friends to a DIYer.

I can't stretch enough how important is to pay attention to your layout, before wasting some of the forum member's time and start whining about how bad your circuit sounds. Mea culpa....

I used some of these really small 1/4 watt resistors. Two of them should have been 10K. I have just found out today that actually I used 100K resistors .

Now it sounds like it should, even maybe it has TOO MUCH treble . Oh well, 0,1uF at the input and 47pF across the clipping diodes. Now it sounds right.

I feel after my first approach to DIY, I've kind of attained a 2nd level where I'm able to debug myself, and starting to understand how some circuits work.

Enough for the rant

You guys rule.