Nobleman bass mod

skrattadu

Member
Hey guys, I'm looking to add a switch for some different bass response values to my ODR1 clone. Which cap(s) control the bass in the Nobleman?

Thanks!
 
What are you trying to accomplish?
Is there too much low end and you're trying to tighten it up for guitar, or are you hoping to mod it to make it more friendly to bass playing?

In the signal path: C1, C6, C19, C20, C21

Indirectly shaping bass response, I suppose C4, C5, C18... Then there's all the caps shaving off highs that shape the overall sound of the circuit, ie how the lows are perceived, the complex tone control... — there's a lot going on.


From what I've read, it's a bassy circuit. Nonetheless, as a bass player I might need more! If you need even more bass, I'd approach it thusly:


Bass Boost

Remove C1. From its input pad on the PCB, run a wire to lug 2 of a DPDT on-off-on switch.

From Lug 1 to Lug 4, attach a 100n cap.
From Lug 2 to Lug 5, attach the stock 100n cap.
From Lug 3 to Lug 6, attach a 220n cap.

Run a wire from Lug 5 back to C1's output pad on the PCB.

You now have 320n in the toggle's up position, stock 100n in the middle position, and 200n in the down position.
You can adjust the caps to taste, whatever sounds good to your ear,



Bass Reduction
Replace R7 (1k5) with a B50k pot. You could try A50k and C50k, too, see where you want the meat of the "bass" control's rotation to sit.

In addition, you could add the C1 switch, but obviously with different cap values:

Lug 1 to Lug 4, attach a 56n cap.
Lug 2 to Lug 5, attach a 47n cap.
Lug 3 to Lug 6, attach a 27n cap.

That'd give you: Up 74n, Middle 47n, and Down a stock-ish 103n.




That's about as much as I'd be willing & able to tinker with the circuit without seriously upsetting its design-balance. Anything more than above and I'd want to fully breadboard the circuit to toy with C3, C11, C16 or Spectrum-related caps etc. I don't know enough to target other specific RC networks, I'd just be trial&error pluggin&playin and using my ears. Actually, I'd use my friend's ears, his are much better nuanced than mine.
 
How I implemented a trim pot. 1.5k to 50kb trim to 2.2u to gnd. Heres some photos. Ive yet completed this build due to missing a few cap values. But I hope this may help someone in the future.

IMG_2357.JPG IMG_2358.JPG Nobels Bass Cut mod x1600.png
 
Change C5 to 220nf.
I'd like to do this myself and maybe add a bit more gain... Thought about just upping the size if the drive pot, or perhaps adding a higher gain boost on a toggle...

The pedal is great, but I like for the controls to be closer to center as far as "less/more"... I try not to build insane gain pedals, but I always like to be able to have it on tap without maxing everything
 
I bet switching the a250k drive pot to a500k would do the trick. If you turn it way up it may get a little out of control. I have yet to mess with an ODR. You might consider swapping the logarithmic 250k to a linear 250k so that the middle of the dial has more resistance. That might make it trickier to dial in lower drive sounds though.
 
Change C5 to 220nf.
I'm trying to understand why you would reduce C5 from 2.2uF to 220nF.

I bet switching the a250k drive pot to a500k would do the trick.

There are diminishing returns by increasing the GAIN pot to 500K. It's only a 6dB (theoretical) increase in gain. It will actually be less because the diode leakage comes into play. Also, we might need to reduce C3.

If you're really dead-set on increasing the gain, you will have an easier time of it by reducing the impedances of C4, C5, R7, R8 & the BASS pot.

You might need a different opamp because the 4558 runs out of bandwidth when the gain exceeds 500x (54dB) or thereabouts.

In any case, this sort of tinkering is best done on a breadboard.

You might consider swapping the logarithmic 250k to a linear 250k so that the middle of the dial has more resistance.

That might be the right move for someone who likes their sweet spot to be near noon and never deviates much in either direction. I know a guy on these forums who does just that.

Me, I want the range to be right so I can set the knob low enough and high enough to suit my purposes and I really don't care if my favorite setting ends up at 9:00 or 3:00.

Another solution is to put a booster in front of the ODR-1.
 
I bet switching the a250k drive pot to a500k would do the trick. If you turn it way up it may get a little out of control. I have yet to mess with an ODR. You might consider swapping the logarithmic 250k to a linear 250k so that the middle of the dial has more resistance. That might make it trickier to dial in lower drive sounds though.
So, I know my way around, but still sort of a noon when it comes to being familiar enough with a circuit to understand what affects another... When it comes to, say, changing pot values on an already-built pedal, I've often wondered if it were possible to just solder *or alligator clip* a different resistor to the existing pot and essentially up the resistance... A good way to experiment instead of desoldering and risking lifting a pad
 
I'm trying to understand why you would reduce C5 from 2.2uF to 220nF.



There are diminishing returns by increasing the GAIN pot to 500K. It's only a 6dB (theoretical) increase in gain. It will actually be less because the diode leakage comes into play. Also, we might need to reduce C3.

If you're really dead-set on increasing the gain, you will have an easier time of it by reducing the impedances of C4, C5, R7, R8 & the BASS pot.

You might need a different opamp because the 4558 runs out of bandwidth when the gain exceeds 500x (54dB) or thereabouts.

In any case, this sort of tinkering is best done on a breadboard.



That might be the right move for someone who likes their sweet spot to be near noon and never deviates much in either direction. I know a guy on these forums who does just that.

Me, I want the range to be right so I can set the knob low enough and high enough to suit my purposes and I really don't care if my favorite setting ends up at 9:00 or 3:00.

Another solution is to put a booster in front of the ODR-1.
I will sorta add to my initial comment on the gain (or anything really). I guess I sorta get "Bluesbreaker syndrome", where some pedals feel like they have to absolutely be cranked, with drive, tone, volume, etc... To me, it leaves me feeling like 9/10th's of the control becomes effectively "useless"... It is more attractive (again, my opinion) to have less of the "undesirable" settings on the table...
I'd only really do this to a pedal build I didn't care for or one that had promise with some traits I KNOW would turn it from just "ok" to great (for my purposes)... or maybe just more versatile.
 
The only way to increase the resistance of a pot is to disconnect at least one lead. To do that you either have to cut the lead or unsolder it. If you're serious about playing "what if?" with a pedal circuit, a breadboard is the way to go. Depending on how the pot is used in the circuit, increasing resistance may do what you expect or it might do the opposite.
 
I will sorta add to my initial comment on the gain (or anything really). I guess I sorta get "Bluesbreaker syndrome", where some pedals feel like they have to absolutely be cranked, with drive, tone, volume, etc... To me, it leaves me feeling like 9/10th's of the control becomes effectively "useless"... It is more attractive (again, my opinion) to have less of the "undesirable" settings on the table...
I'd only really do this to a pedal build I didn't care for or one that had promise with some traits I KNOW would turn it from just "ok" to great (for my purposes)... or maybe just more versatile.
Or maybe you need a different pedal. ;)
 
Or maybe you need a different pedal. ;)
In some cases, yes, for sure.

Some builds don't suit me, and it's fairly quick to determine... but some sound really good... just shy of what I'm wanting it to do... or just wanting a bit more than it offers. Sometimes a recipe is good, just needs an extra dash of seasoning to make it just right... vs throwing it out and trying to find another new recipe altogether 🤣
 
I bet switching the a250k drive pot to a500k would do the trick. If you turn it way up it may get a little out of control. I have yet to mess with an ODR. You might consider swapping the logarithmic 250k to a linear 250k so that the middle of the dial has more resistance. That might make it trickier to dial in lower drive sounds though.
You were correct. I swapped to a 500k, and the pedal oscillates at the highest settings... like a modulation effect at a rapid rate
 
Shouldn't do that.
I saw another forum member have the same issue (also noted when the gain was turned up).
It doesn't really manifest in normal playing... but if you lightly touch a string you can hear it. I didn't make any other adjustments or modifications so its strange this would occur. You mentioned before that the 4558d op amp can only handle so much gain /bandwidth. Could this be the issue manifesting itself? or perhaps a different capacitor/resistor is needed in the gain section to compensate for the increased pot value.

Any suggestions for an op-amp that would
 
This circuit should not oscillate. If it does, then there is a problem with stray coupling either thru the proximity of traces, off-board wiring, power or grounding.

Wanna post photos of your build?
 
This circuit should not oscillate. If it does, then there is a problem with stray coupling either thru the proximity of traces, off-board wiring, power or grounding.

Wanna post photos of your build?
I do have it on a "audition" board instead of in a case... I didn't notice the oscillating when I had the 250k drive pot installed, BUT, I was running a hammer drill through concrete and brick all day when I first tested it... I'll give it another glance just to be sure I didn't miss anything and then post photos.
 
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