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WIGGLING 'LITE' IN GUEST MODE

Korg Monotribe modifications thread
MUFF WIGGLER Forum Index -> General Gear Goto page Previous  1, 2, 3 ... 34, 35, 36, 37, 38, 39  Next [all]
Author Korg Monotribe modifications thread
rarara
Scott Willingham wrote:
rarara wrote:
Scott - am now considering the PWM mod (is there a soundclip anywhere??), but do you know how compatible it is with:

a) the synth mute mod where the waveform selector is grounded
b) the 'hard square' mod mentioned above.

I suspect the mute mod makes no difference, but was thinking of doing the other too.

Sorry, no sound clips. I play with synths, but rarely record. confused

For muting, I recommend shorting Pin 4 of the wave selector switch to ground (the square-wave). This doesn't interfere with the PWM mod. Note that you have to select the square wave to do muting in this case. I don't recommend muting on the output side of the switch, mainly because when a Tri wave is selected, you will short an opamp output to ground.

I took a look at that 'hard square' mod and listened to the demo (which sounds effective). The description is not completely clear, but it sounds like you just wire a capacitor and switch between pins 1 & 2. But I'm having a hard time visualizing how this works to improve the waveform's duty cycle. hmmm..... This mod shouldn't interfere with the PWM mod as long as the switch is open.

what is the pin orientation in your photo? does it run

1 4
2 5
3 6

so you have 5+6 shorted? or are they 2+3?
Scott Willingham
rarara wrote:
what is the pin orientation in your photo? does it run

1 4
2 5
3 6

so you have 5+6 shorted? or are they 2+3?


I think the orientation is

4 5
Gap
3 6
2 7
1 8

Kinda weird, but that's how it relates to the Monotribe schematic. Pins 3 and 6 are the common pins. Pins 7 and 8 are the ones I shorted. They get connected to pin 6 in the Tri and Saw selections. Pin 5 is shorted to pin 6 when Square is selected.

Hope that helps!
rarara
janmaat wrote:
I've managed to make a simple line out for the drums. I you open the 'tribe, you can spot where the pot for drums volume is soldered onto the PCB: two big blobs and three small ones. I soldered the left of the three small ones to tip of a jack out, and jack out shaft to ground. Result is a (mixed) drum out independent of the pot. The pot still functions as before blending the drum mix into the complete mix for the mt line out. I guess if you solder to the middle of the three legs, your drum volume would influence the drum line out, but that's theory since I'm happy with my steady drum out.

anyone care to expand on this? I have tried and no joy - trying to test by feeding the new drum out into the audio-in to filter drums. and all that i can determine happens is that if i have the drum volume pot half way then plug earphones into the new seperate jack, it cuts the sound of the drums from the main out (?) and nothing comes out of the new jack either.
Scott Willingham
rarara wrote:
janmaat wrote:
I've managed to make a simple line out for the drums. I you open the 'tribe, you can spot where the pot for drums volume is soldered onto the PCB: two big blobs and three small ones. I soldered the left of the three small ones to tip of a jack out, and jack out shaft to ground

anyone care to expand on this? I have tried and no joy - trying to test by feeding the new drum out into the audio-in to filter drums. and all that i can determine happens is that if i have the drum volume pot half way then plug earphones into the new seperate jack, it cuts the sound of the drums from the main out (?) and nothing comes out of the new jack either.


Are you plugging the earphones directly into the new "drum out" jack? The suggested mod is unbuffered, so it has a fairly high output impedance. Thus it can drive something like a line-input to a mixer. Earphones, especially earbuds, have a very low impedance (like speakers). The drum-out mod cannot drive this load very well. Since you are tapping into the main signal chain inside the Monotribe, this also cuts the volume of the drums in the main mix.

Try feeding the new output into a mixer or computer audio interface to see if you get a drum signal.
rarara
argh, that's a pain - I want to feed the new drum jack directly into the audio in so will now have to find a more suitable mod very frustrating

what is the level expected with the audio in btw? as a quick test of an iPod signal didn't seem to work either
Scott Willingham
rarara wrote:
what is the level expected with the audio in btw? as a quick test of an iPod signal didn't seem to work either


Are you triggering the Monotribe? The external input does not automatically pass through the VCA without a gate. Try pressing the ribbon or running a sequence while you feed in the iPod.

(The VCO will sound as well. Hence the popularity of mute mods...)
rarara
yes, got a pattern running and the wave to ground to mute the synth. will try again with another cable.

any idea about a drum to vcf mod? have seen a video but nothing with any detail on how it is achieved
rarara
well the input seems fine when i don't by mistake use the volca bass sync cable instead of an audio cable d'oh! (which incidentally sounds good fed through the monotribe filter).

will try that drum out again now, just need to resolder a wire first
rarara
rarara wrote:
janmaat wrote:
I've managed to make a simple line out for the drums. I you open the 'tribe, you can spot where the pot for drums volume is soldered onto the PCB: two big blobs and three small ones. I soldered the left of the three small ones to tip of a jack out, and jack out shaft to ground. Result is a (mixed) drum out independent of the pot. The pot still functions as before blending the drum mix into the complete mix for the mt line out. I guess if you solder to the middle of the three legs, your drum volume would influence the drum line out, but that's theory since I'm happy with my steady drum out.

anyone care to expand on this? I have tried and no joy - trying to test by feeding the new drum out into the audio-in to filter drums. and all that i can determine happens is that if i have the drum volume pot half way then plug earphones into the new seperate jack, it cuts the sound of the drums from the main out (?) and nothing comes out of the new jack either.

OK, after using the correct cable oops I can confirm that this works fine. The level of the drums going into the filter isn't as high as the drums can be normally, but pretty workable (and could go via my mixer first i guess for a bump). Its also then possible to use the rhythm volume knob to have both normal drum sounds as well as the filtered version.

Now to do the drum decay etc mods...
Pase
Hi, are there any wigglers (maybe based in Italy or EU) that offer a professional modification service? I ask 'cause I've just bought an used unit and I'd like to transform it in a little monster, but I'm not able to do it by myself. Send me a pm if you're interested, thanks! wink
hamildad
Hi Pase,

I cant help you on the Monotribe, but I've just came back from a holiday in Sestri Levante, what a lovely area of Italy that is. we were in Zoagli, but took the train to Sestri most days to relax...

Seemed like there are a few interesting things happening in that area as well..

good luck finding someone to mod the tribe, I've added midi to mine, but not done anything further.
Pase
hamildad wrote:
Hi Pase,

I cant help you on the Monotribe, but I've just came back from a holiday in Sestri Levante, what a lovely area of Italy that is. we were in Zoagli, but took the train to Sestri most days to relax....

Glad to hear this, I hope you had good time here in Liguria wink
PolarAC
Hello. I’ve ran into an issue after I’ve done my mods. I was wondering if anybody had some advice.

For some reason, the synth volume level is now quite low on my MT. I’ve done the midi, drum decay, & de-click mods on my machine. Before the mods, the synth & rhythm levels were nearly equal at max (with the synth having the edge). After the mods, I’ve only been able to use the MT as a drum machine since the synth level has been nerfed so bad.

Anybody know where the issue may lie. If not, is there a synth/vca level mod that can increase the volume?
Scott Willingham
PolarAC wrote:
For some reason, the synth volume level is now quite low on my MT. I’ve done the midi, drum decay, & de-click mods on my machine. Before the mods, the synth & rhythm levels were nearly equal at max (with the synth having the edge). After the mods, I’ve only been able to use the MT as a drum machine since the synth level has been nerfed so bad.


I would suspect your de-click mod. Perhaps the capacitor you added is way too big, or it is damaged and very leaky.
PolarAC
Scott Willingham wrote:
PolarAC wrote:
For some reason, the synth volume level is now quite low on my MT. I’ve done the midi, drum decay, & de-click mods on my machine. Before the mods, the synth & rhythm levels were nearly equal at max (with the synth having the edge). After the mods, I’ve only been able to use the MT as a drum machine since the synth level has been nerfed so bad.


I would suspect your de-click mod. Perhaps the capacitor you added is way too big, or it is damaged and very leaky.


I see. I'll go ahead and replace it with a new smaller cap. Hopefully that will get it back to normal. Thanks
mckenic
Before you replace the cap - remove the old one and check if everything is back to normal (click included of course)...
rotallicso
Just wanted to say that I read the last 10-20% of this thread like a kid at christmas time (Thanks Scott!) - the years of procrastinating have paid off in that there is a smorgasbord of mods to chose from - as much as I'm an admirer of Daren's epic 'factory' builds I'm mostly interested in doing my own (that's 90% of the fun for me anyway - ps, same applies to sound-design, but Daren's druma patches for A4 are sublime) - a little bit of the procrastination was to do with procuring the right components at the time, but I'm set on using the spare 2.5mm>midi cables that came with the Line6 midi mobilizer, so it should be very easy to accommodate those (do it very cheaply without the stepped drill bit too) and leave room for misc trimmers, jacks and switches - i'd like all mods to be selectable (yeah, even the click ... part of the charm)
.
wondering if those with an experienced eye who've gone on this trip (and now with the benefit of hindsight) would care to propose their top five (solutions* from many above) in terms of simplicity/efficacy ? ... midi is a given, I guess I'm saying that it is a crazy long thread and there are competing strategies for similar ends, I can't use prior knowledge to 'know' what sounds the best approach - i'd like to give variation to the kick and anything to snare/hat would be a bonus - trig out(s) - separate the rhythm voice - de-click - not so bothered about extensive synthvoice tinkering (already great), but easy defeatable ones are a possibility - one main aspect that's a bit of a pity (probably for very good reason) is the user choice between cv in and sync in ... I'm guessing this is all locked in firmware and not something that can be hacked to work electronically
- a big pluspoint mod would be a good clean way to internally increase overall gain (even fixed) for integration with other gear expecting hotter output directly
.
sorry, bit of a meandering non-question, just wiping my feet I s'pose before I come in with detailed questions
is there a mac/web based electronics design tool that anyone would recommend for circuit design 'modelling' ? this tinkering is part of a baby step towards making e.g. a more modular centric hackfest within perhaps an ms20mini .... all that free space and panel room : ) ... there must be a mod thread for that somewhere, the ones I have seen are really unambitious and tame compared to what's panned out here already
.
thoughts/pointers welcome (even re uk based component suppliers or tools/sw of the trade to make life easier (on the cheap) besides voltmeter) -particularly keen to source those subtle 3.5mm mono jacks used by a909 and daren - particularly for a potential ms20 modspree (or links to more ambitious ms mod blogs)
.
anyway - thanks to all for sharing above, great stuff, inspiring !
mckenic
Without a doubt, even before midi, before anything else - the simple de-click! It is essential imho!
rotallicso
... Indeed, but which is *the* simple one, the least contestable ; ) this was my thrust ...
mckenic
Scott Willingham wrote:
Another kudos to Marmad for publishing clear directions for the click/thump reduction mod. I modified mine about two years ago (2.2uF), got busy and lazy and never got around to sharing. d'oh!

I think it's a must-do, right after doing the MIDI-in mod. A bit of click on the attack of a sound can be considered "character" but clicking on the release is just annoying. Also, one of my favorite wiggling techniques on the Monotribe is to record a sequence and then play the ribbon with the gate-time button down. I love to interactively mute and choke the sequenced notes. Shame on Korg for not fixing this in the firmware.

Technical notes:

The software envelopes are created by pulse-width modulation (80kHz) filtered with a Sallen-Key filter. The stock minimum rise- and release- times are less than 100 us. With 2.2uF added, the minimum rise/fall times are about 2 to 3 ms.

The VCA circuit has an offset adjustment trimmer. I replaced all the critical resistors in my VCA with 0.5% types and tried to trim out the clicks/thumps. This partially works but is not reliable. The problem is that the filter is DC-coupled to the VCA (good for bass response) and that the DC output of the Korg-35 style filter varies with the filter settings. So too-fast envelopes cause audible steps in the VCA output.

EDIT 2015.03.25: For completeness, here's a photo of the click/thump mod in my MT:



I used a tantalum cap because that's what I had laying around. IMO, any capacitor type will work fine.


mckenic wrote:
Well I decided to get off my ass and try the de-click mod...

love

Just WOW!

As with the pic above - I just used a 10uF cap - negative to the Yellow in the pic below & positive to the red point. Did nothing else, cause MAN am I happy!



applause


Two solder points to total bliss!!!
thumbs up
grenert
De-click is essential, IMO. I found mine difficult to listen to with the clicking. I think I used 2.2uF on mine. You could play around with different values to see what works best for you. MIDI of course because it is so easy and useful.

The only other ones I did were the PWM mod (excellent! really changes the character of the sound) and adding a switch to remove the oscillator from the circuit. I actually switched the oscillator out, rather than shorted it to ground.

I thought I was going to do some drum sound mods, but in the end, I like them quite a bit as they are. Not worth the hassle of soldering and drilling to me.
rotallicso
thanks, seems like there's a few safe bets, once I've whet my appetite with the definites i'll revisit the whole thread for guidance/inspiration
Pase
Sorry for the crossposting from the microgranny thread, but maybe here I'll get an answer to my midi noob question:
Does anyone knows if I can midi sync a Microgranny with a midi modded monotribe as master?
If I'm correct the monotribe convert the sync input in midi clock output, so if I have a first monotribe that send sync to a second monotribe, does it send midi clock to the microgranny?
Samaepstein
Pase wrote:
Sorry for the crossposting from the microgranny thread, but maybe here I'll get an answer to my midi noob question:
Does anyone knows if I can midi sync a Microgranny with a midi modded monotribe as master?
If I'm correct the monotribe convert the sync input in midi clock output, so if I have a first monotribe that send sync to a second monotribe, does it send midi clock to the microgranny?


Yes!
Pase
Great! Thanks Guinness ftw!
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