Do we have a Zorkmid OD schematic hiding somewhere?
- Thread starter HamishR
- Start date
I just posted a build report and quoted you in it. Did you build the PCB? I thought that it sounded quite cool.
As a starting point set mids to off, bass to noon and treble to max. Volume to 2oc and gain to off for boost and higher for drive. Both switches in the middle position.
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The Zorkmid
is a uniquely designed clean boost, overdrive and distortion pedal that offers a wide range of dirt tones while being very user friendly and easy to dial in. It has BASS, MID, TREBLE, GAIN and VOLUME controls along with a 3-way CLIP switch and a 3-way CUT switch to make it work with a wide range of styles, guitars and amps.The MID control comes first in the design and is an active mid boost circuit. It acts like a flat buffer at "0" and increases the mid range as you turn it up. It adds some clipping of its own around 2 o'clock and up to hit the main clipper hard.
The BASS cut control is also an active circuit and comes after the MID control. At settings below 2 o'clock it reduces low end, and above 2 o'clock it offers a bass boost that's about +6dB @ 280hz to thicken things up if needed.
Next is the main clipping circuit. It goes from clean, early break up and into overdrive. Crank the MID control and it gets into distortion territory. There is a 3-way CLIP switch to give some different levels of compression and harmonics. At low gain settings the levels may not be large enough to be affected by the CLIP switch, but you'll notice the different settings at mid to hi gain levels.
Last is the passive Treble control followed by an output amp to make it loud... The CUT switch is located at the output to help shape the overall eq of the pedal. The center position is voiced flat. To the right it rolls off the hi-end at -3dB @ 2.75khz to help tame the hi-end with brighter amps/speakers, and to the left it does the same while also rolling off the lows at -3dB @ 120hz to tighten up the bass.
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So it sounds like the mids control is working as intended but overall it's lacking brightness. I seem to need the treble control pretty much on full, and that's with the cut switch in the middle setting. I just want to make sure I got all the right values in the right places. It's hard to check once the parts are in place. It may well be that it's working as intended. In that case I might want to change a few things!
I set the treble to full as well. I mentioned in my build report that it’s on the dark side otherwise. It’s mentioned as a passive treble at the end so I think it only cutting treble? For me the tone control switch also doesn’t work to my liking, would prefer a treble increase instead of a treble roll off.
Increasing the mids would benefit from a little more treble.
Hey Harry - just read your write-up. Yup, that's pretty much how mine sounds. I would like a bit brighter sound! That's where a schematic would be handy. And yes, 10K for a Treble pot may seem to offer little adjustment but it depends entirely on the circuit and how it is integrated. I have a few ODs which use a C10K Treble pot and they work perfectly well. If it is designed well 10K can be all you need. 
It's late here now. I'll give it another try tomorrow. Thanks guys!
It's late here now. I'll give it another try tomorrow. Thanks guys!
That circuit adjusts the treble from -3dB@7khz down to -3dB@450hz
R9 should be 3k3 Also change R10 to 3k3 to bring in some more highs at the expense of some bass boosting from the bass controlHey Harry - just read your write-up. Yup, that's pretty much how mine sounds. I would like a bit brighter sound! That's where a schematic would be handy. And yes, 10K for a Treble pot may seem to offer little adjustment but it depends entirely on the circuit and how it is integrated. I have a few ODs which use a C10K Treble pot and they work perfectly well. If it is designed well 10K can be all you need.
It's late here now. I'll give it another try tomorrow. Thanks guys!
Hi Paul
Is it designed to work with a standard range of Amps coz as you know some Amps that tend to be on the dark side or dont have a Bright switch?
Now that I understand how it is meant to be used everything makes a lot more sense! I will probably still try to add a hint more treble but really it sounds great as-is. If you use it as Paul suggests it works very well. I was approaching it as I would any other OD but that doesn't really work in this case.
I don't think I will be doing much to change this one. Usually I see an OD as a starting point and inevitably start fiddling until I make it suit my setup. Sometimes it might be a cap or two and sometimes I might change half of the circuit. I'm far from expert but that's why I build my own. The Timmy has been fantastic as a starting point for some cool pedals and is obviously a great circuit in its own right. This one might be beyond my limited abilities to tweak. I don't see my versions of the Timmy to be better, just good for me and what I do with my guitars and my amps. In the same way that we all tweak our guitars and FX chains etc I like to tweak my overdrives, as they are a crucial part of the overall sound.
That's why I love this hobby.
I don't think I will be doing much to change this one. Usually I see an OD as a starting point and inevitably start fiddling until I make it suit my setup. Sometimes it might be a cap or two and sometimes I might change half of the circuit. I'm far from expert but that's why I build my own. The Timmy has been fantastic as a starting point for some cool pedals and is obviously a great circuit in its own right. This one might be beyond my limited abilities to tweak. I don't see my versions of the Timmy to be better, just good for me and what I do with my guitars and my amps. In the same way that we all tweak our guitars and FX chains etc I like to tweak my overdrives, as they are a crucial part of the overall sound.
That's why I love this hobby.
R10 is 4k7 now so I will try a 3k3 as well. I don’t mind a little less bass boosting as there’s plenty of that already.
EDIT: just replaced the R10 4k7 with a 3k3 resistor and it improved the treble a bit and also the response of the bass.
Thanks @paulc!
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Don’t forget to change R9 to 3k3 along with R10.
Also to make the mid control a little less “peaky” you could lower the “Q” by changing the 2k2 resistor to 3k3 and the 1n5 cap to 1nf. This will give the same center frequency but with a little less gain and a little broader bandwidth
Also to make the mid control a little less “peaky” you could lower the “Q” by changing the 2k2 resistor to 3k3 and the 1n5 cap to 1nf. This will give the same center frequency but with a little less gain and a little broader bandwidth
