Mojito Mark 3

[Chuck D. Bones]

Teaser alert!

Same boost & distortion stages. Better pre-distortion bass cut, Baxandall active treble & bass controls. Yeah, it takes a few more parts.

LEVEL - TREBLE - BASS - TIGHTNESS - DRIVE - BOOST

 

[fig]

My Mojito never fails to please, but perhaps this stiffer blend is in order. Nice!

 

[cooder]

More parts we have to throw at it. Noice!

 

[Dan0h]

Still love mine. I’d build the Mark 3.

 

[Nostradoomus]

Chuck, can you just start some kind of monthly PCB delivery subscription? I’m still on MK1

 

[music6000]

Teaser alert!

Same boost & distortion stages. Better pre-distortion bass cut, Baxandall active treble & bass controls. Yeah, it takes a few more parts.

LEVEL - TREBLE - BASS - TIGHTNESS - DRIVE - BOOST
View attachment 56281

Maybe like this:

 

[Chuck D. Bones]

A show of hands... Who has a Mojito and regularly steps on the BOOST switch?

FYI
Mark 1 has no BOOST switch. A very limited number were built (one AFAIK).
Mark 2 is offered by PedalPCB and a couple of independents. Has a boost switch. The PedalPCB version fits in a 125B. You need ballerina feet to operate it.
Mark 3 breadboard is shown above. I'm fine-tuning the tone stack, and it's damned close to done as we speak.

 

[szukalski]

Personally, a single footswitch with the boost always there, like the Honeybeest, is more useful for me. (Or a single footswitch with a dual relay and hold function).

 

[cooder]

No two footswitches for me in a 125B. No ballerina feet here. One stomp in that size is me.

 

[music6000]

I would have it so you have a choice, you can jumper the Boost pads & have a single Footswitch.
or we could have a Mark IV!

 

[Dan0h]

I only hit the boost on mine maybe 5% of the time I use it.

 

[music6000]

I only hit the boost on mine maybe 5% of the time I use it.

It wont last long if you keep doing that, just a press of your foot or finger will do the job!

 

[szukalski]

Realistically, most of us will have a boost pedal in their signal chain. Down-vote me if I'm wrong!

 

[cooder]

Realistically, most of us will have a boost pedal in their signal chain. Down-vote me if I'm wrong!

Just one?

 

[mdc]

1590BB in landscape is a nice size for two footswitches imo. Anything smaller than that is a nightmare for anything other than home use.

 

[music6000]

1590BB in landscape is a nice size for two footswitches imo. Anything smaller than that is a nightmare for anything other than home use.

Just For You:

 

[G.G.]

For me, I usually fiddle with the switches until I get a sound I like and then rarely touch them again. A lot of times I'll just set them up as jumpers on the board so I don't need extra parts or drill holes in the enclosure.

 

[Chuck D. Bones]

Here's the schematic.
The 1st stage is unchanged from the original version except the BOOST switch is deleted. TIGHT is a low-cut with maximum cut (minimum bass) at full CW. This replaces the BASS control in the original version. Q2 is a unity gain buffer that prevents the TIGHT circuitry from loading Q1. The 2nd stage is unchanged from the previous version. U2 and surrounding parts form two active filters. I first tried a Baxandall tone stack. Because the Mojito is very mid-forward, I found I was only using the top half of rotation on the BASS & TREBLE knobs. So I switched over to the boost-only bass & treble filters shown below. Setting BASS & TREBLE to zero provides a flat freq response from the top of C11 to the output. BASS provides up to 12dB boost at 85Hz. TREBLE provides up to 12dB boost at 5KHz. The BASS & TREBLE filters were inspired by the BOTTOM & TOP filters in the ROG Thunderbird.

 

[fig]

Q2 to the rescue!

 

[music6000]

Here's the schematic.
The 1st stage is unchanged from the original version except the BOOST switch is deleted. TIGHT is a low-cut with maximum cut (minimum bass) at full CW. This replaces the BASS control in the original version. Q2 is a unity gain buffer that prevents the TIGHT circuitry from loading Q1. The 2nd stage is unchanged from the previous version. U2 and surrounding parts form two active filters. I first tried a Baxandall tone stack. Because the Mojito is very mid-forward, I found I was only using the top half of rotation on the BASS & TREBLE knobs. So I switched over to the boost-only bass & treble filters shown below. Setting BASS & TREBLE to zero provides a flat freq response from the top of C11 to the output. BASS provides up to 12dB boost at 85Hz. TREBLE provides up to 12dB boost at 5KHz. The BASS & TREBLE filters were inspired by BOTTOM & TOP filters in the ROG Thunderbird.

View attachment 56465

As Per Schematic: