Mids Boost Pedal question

[jwyles90]

Hey all!

A friend of mine asked me recently if I could build him a pedal that does essentially what a Tube Screamer does, just without the gain stage. So something that boosts the mids specifically, has some semblance of a tone control, compresses the signal a bit like a Tube Screamer does, but no gain. I did a bit of research and it seems like the Maleficent Mids would be pretty close to what he's looking for, but I've got a couple questions. Sorry if they seem straightforward or obvious, I'm still learning a bit about circuit design and all that:

1) Does the compression that he's wanting come from the fact that there is a gain stage in a tube screamer? Or, in other words, is it even possible to do that without a gain stage?
2) Would the Maleficent Mids be able to scratch that compression itch for him, or is there another mids boost type pedal out there that I'm not seeing that would get closer?

Thanks everyone!

 

[spi]

I wonder if a modded tube screamer would do the trick?

You can use higher clipping threshold on the diodes (such as LEDs to get more headroom), or even remove the diodes completely. The TS in my avatar has both these options on the switch: in the middle position the diodes are removed and it becomes a boost. When running it this way, it doesn't sound as good with the knob gain turned up, but sounds good with the gain down and has plenty of boost. So I'm thinking if you build a TS with no clipping, and then reduce the gain knob range or even replace the gain knob with a fixed value.

Do you breadboard?--you could experiment with this approach.

 

[Robert]

There will be a gain stage in any boost pedal, that doesn't necessarily have to mean it has any dirt or clipping though.

What about the 6-band EQ?

 

[jwyles90]

There will be a gain stage in any boost pedal, that doesn't necessarily have to mean it has any dirt or clipping though.

What about the 6-band EQ?

Yea you're right about that, I guess I was curious if the compression he's looking for is coming from the dirt/clipping or if it's possible to still get that kind of stuff without adding gain or clipping the signal.

A 6-band EQ would totally work logistically, I think he's just looking for something a little more straightforward for boosting mids. He does gigs out and about and wants something that could function both as a little jazz mids boost while also being useful for tightening up some distortion when he gets into more heavy metal territory.

Do you breadboard?--you could experiment with this approach.

So I'm only just now starting to dip my toe into the veroboard side of building, and breadboarding is something I've been working up to trying but haven't gotten around to yet. I was thinking a modded tube screamer with the gain set super low would work too, I'm just not very confident in my abilities to make that since I've yet to breadboard anything or build something that wasn't already laid out in a PCB. Obviously, there's no time like the present to start, but I'd ideally like to build him something that isn't me just experimenting with a circuit layout (until I'm at that point).

 

[HamishR]

There are a number of mid-boost kinda pedals without dirt. One which comes to mind is the Leonora Boost, essentially a Klon without diodes for clipping. The Chickenhead is a treble-booster which boosts mids but can be used as a more full-range boost depending on where you put the tone knob - in some ways it is the predecessor to the TS because it fills a similar role but to my ears it has more character. You can easily build it with a low-gain NPN silicon transistor if you like - I have and it works well.

The Wonder Drive is similar to what your friend is asking for. It's a clean boost with an excellent tone for pushing an already dirty sound.

Or you could simply build a TS without diodes, even leaving out the gain pot. Just hardwire the gain pot at zero with a piece of wire. There are lots of options!

 

[jwyles90]

There are a number of mid-boost kinda pedals without dirt. One which comes to mind is the Leonora Boost, essentially a Klon without diodes for clipping. The Chickenhead is a treble-booster which boosts mids but can be used as a more full-range boost depending on where you put the tone knob - in some ways it is the predecessor to the TS because it fills a similar role but to my ears it has more character. You can easily build it with a low-gain NPN silicon transistor if you like - I have and it works well.

The Wonder Drive is similar to what your friend is asking for. It's a clean boost with an excellent tone for pushing an already dirty sound.

Or you could simply build a TS without diodes, even leaving out the gain pot. Just hardwire the gain pot at zero with a piece of wire. There are lots of options!

I’ll have to check those out! I was thinking of trying to mod a TS like that, so I’d basically just jumper the holes in the PCB for the gain pot to take that out of the circuit?
I’ll have to throw that idea his way as well and see if that sounds like something he’d be into.

 

[HamishR]

Yup. If you turn a gain knob to zero it is virtually making a clean connection between pins 1 & 2. So solder a wire between the holes in the PCB which correspond with those pins. If the gain pot is 500K you can always solder a 470K resistor between the holes for pins 2 & 3. A 500K pot is rarely exactly 500K so 470K will be near enough.

And you don't need to use the PCB style pots either. If you want to put the Tone pot up next to the Volume pot in the enclosure you can just use a regular solder-lug pot and wire it to the board. It might look neater that way.

 

[jwyles90]

Yup. If you turn a gain knob to zero it is virtually making a clean connection between pins 1 & 2. So solder a wire between the holes in the PCB which correspond with those pins. If the gain pot is 500K you can always solder a 470K resistor between the holes for pins 2 & 3. A 500K pot is rarely exactly 500K so 470K will be near enough.

And you don't need to use the PCB style pots either. If you want to put the Tone pot up next to the Volume pot in the enclosure you can just use a regular solder-lug pot and wire it to the board. It might look neater that way.

Thanks for the info! Yea I’d use the solder lug ones to wire them up a little differently if I were to go that route. I generally prefer PCB mount pots but having that extra flexibility is nice

 

[tcpoint]

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