Unique feature for an overdrive pedal?

[aron]

[niektb]

So I've been reading through the suggestions a bit (and other websites ofc) and it appeared to me that the tone control is the Tubescreamer's weakest point. Hence I'm biased into adding a variable mid control. I've simulated the Framus Cobra Mid Control (which is said to give some nice scooped sounds) in TINA-TI and got the following results (the upper curve is the clean signal and then I increased the pot value with steps of 25%) (the drive knob is at 100% and the tone is at 0%)





How does this look? I'm not too sure about it, the first 25% mainly reduce volume and don't affect the tone really

[garcho]

what is your limit on number of controls? knobs, switches and stuff.

do you plan on breadboarding it first? or a proto-build?

[PRR]

> See if the PostImage tool works now?

Yes: http://www.diystompboxes.com/smfforum/index.php?topic=117747.msg1094496#msg1094496

[niektb]

Apparently the PostImage tool works Can we get on-topic again?

The former simulation results where rather poor because of (what I think) an impedance mismatch. I placed the mid control after the tone control and it looks much healthier

what is your limit on number of controls? knobs, switches and stuff.

do you plan on breadboarding it first? or a proto-build?

Don't have a real limit on that, as long as there is space. Though on the other hand I like to minimize it to ease assembly and usage.

Nai, no breadboarding. I plan to order my PCB's at allpcb.com where you can get 10pcs for $5

[Ben N]

Fulldrive style ersatz "boost"; switchable octave a la this.

[niektb]

Fulldrive style ersatz "boost"; switchable octave a la this.

Seems like your link is dead

Verstuurd vanaf mijn Lenovo P2a42 met Tapatalk

[bool]

Perhaps try to add a mid-band gyrator based control to the existing TS one.

This sould be the easiest and quick to implement imho.

[niektb]

Perhaps try to add a mid-band gyrator based control to the existing TS one.

This sould be the easiest and quick to implement imho.

In my most recent version (check my simulation post) I have a passive mid-cut filter, is that what you mean?

[bool]

No. Your passive mid control ... I don't know, it seems awkward.

A TS tone control already has a way to simply "bolt" on a mid-circuit. You just need to add one potentiometer and a corresponding gyrator circuit.

On geofex site is an easy to follow explanation; you only have to implement it in a TS circuit. (Look for "notches and peaks" schem).

http://www.geofex.com/article_folders/eqs/paramet.htm

[niektb]

It's just an ordinary Bridged-T notch filter...? In fact, you can find it on the same page as you linked to (it's last image on the page, number 4):

[niektb]

Hey fols, statusupdate on my end 

I've decided to go with the passive mid control, I've ordered the components and I drew a PCB layout! 




(I have to clean up the silk screen, but I'm not entirely sure about the knob placements yet)

[Ice-9]

Looks like you PSU jack is wired for centre positive instead of the normal centre negative, is this how you intended it ?

[niektb]

Good catch! I was a bit confused by the way the schematic symbol was drawn (though, in practice it wouldn't have mattered too much since I will be using a 2-pins case-mounted DC-jack)

[niektb]

Finally came around to finish this project! 





However, the tone knob doesn't seem to be doing a lot... I hear the background noise subtly darkens but nothing noticeably happens to the guitar tone... I double-checked schematic and part values on the board, they're all correct. Anybody an idea on what's going on?

[EATyourGuitar]

you mentioned that you wanted to ditch the transistor buffer for better noise floor. the transistor will take any power noise and multiply it. you don't need to eliminate all transistors. you only need to reduce power rail noise. an opamp will still have power rail noise but that noise is pretty much as-is for ripple on a single supply buffer. they both benefit from power decoupling but the transistor will benefit more.

[Steben]

Higher knee voltage of diodes (LEDs fe) gives slightly harder clipping sound (bigger ratio of clipping voltage and original signal). I think it is a major tone selection.

[Rob Strand]

I hear the background noise subtly darkens but nothing noticeably happens to the guitar tone... I double-checked schematic and part values on the board, they're all correct. Anybody an idea on what's going on?

To me the impedance of the bridge-T network is too high for the 10k load.
You should see a large gain drop until the 100k pot is set to the 1k side (ccw on you schematic).

Try temporarily (or permanently) moving the 10k at the input of the second opamp to just after the 1k ie. before the added mid tone control.

Check your DC voltages.

[R.G.]

The devil makes me want to say that not being a tube screamer variant would be unique.

[suryabeep]

What program are you using for designing the PCB? Also, what spacing do you use for the footswitch and I/O jacks? I'm using Eagle at the moment and I'm not able to figure out those nice PCBs like the one you have there