x0xi0 Full Mod kit Details

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bcbox
 
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Joined: Thu May 25, 2006 1:30 am

x0xi0 Full Mod kit Details

Post by bcbox »

I have not written the Users Manual for the Top panel mods yet so I’m adding a brief description of each new feature below so you can get a sense for what it’s all about. I’ve made several changes since the old prototypes that to this point I haven’t shared with everyone. Please take this as a temporary description of the new features until I can finish the proper manual! Refer to the panel outline rendering below for the location of all the new top panel controls (double click on pic for bigger size).

VCO’s (VCO2):
The second VCO is the same design as the original TB-303 VCO. However it has an independent tune range of -1 to +3 octaves relative to VCO1. There is a coarse and fine tune control for VCO2. The original Tune control is the Master tune of both VCO’s. Each VCO has a waveform select switch to choose between saw or square. Each VCO has a Level control. When the VCF Overdrive switch is in the ‘off’ position and the Level controls are at max the signal level is equal to the stock x0xb0x. When the VCF Overdrive switch is in the ‘on’ position the VCF can be overdriven by each VCO by increasing the Level controls past 30%. VCO2 can be fed a separate CV from VCO1 by inputting a CV to the ring of the Mix Out Jack (this will require you to make or buy a Y-cable). When a CV is input here it bypasses the internal or external CV that goes to VCO1, so VCO2 has an independent CV control. When no cable is plugged in VCO2 gets the same CV as VCO1 (the internal sequencer and the external CV In). The Tune and Width trimpots for both VCO1 and VCO2 are easily accessible from the front panel without having to open the enclosure. There are four small holes by the Tune controls where the trimpots can be easily adjusted.

VCO Xmod:
The Xmod control determines how much one VCO modulates the frequency of the other. The switch above the Xmod control determines if VCO1 acts on VCO2 or vice versa. At the minimum setting there is no frequency modulation.

Noise: There is an analog noise source that is mixed with the VCO’s and the external input to the filter. The noise is pseudo-pink noise, actually somewhere between white noise and pink noise that I liked best. When the control is at minimum there is no noise added.

ENV2 (Envelope 2):
There is a new envelope generator with extensive routing. The mode can be selected as Attack/Decay or Attack/Release. In AD mode the envelope decays as soon as the attack phase ends, independent of when the keyboard (or sequencer) gate is released. In AR mode the release phase does not begin until the gate is released. If the attack time is reached before the gate is released the envelope will stay at maximum until the gate/key is released. The attack time is variable between 1ms and 8 seconds. The decay/release time is variable between 1ms and 12 seconds. There is a Shape switch to select the envelope shape as normal or inverted. The Env Trg switch determines if the envelope is triggered by all notes or by accented notes only. Also, when the Trg Alt switch is in the ‘on’ position the operation of the Env Trg switch is changed and now selects the trigger source as either all non-accented notes or slides! . The Depth 2 Control determines how much ENV2 affects the VCA (volume) or VCO (Freq Mod) depending on the position of the VCO/VCA switch. If the VCO is selected as the destination of the Depth 2 control by default VCO1 is affected. If the ENV2 to VCO2 switch on the rear panel is in the ‘on’ position then ENV2 will modulate the frequency of both VCO1 and VCO2. When VCA is selected as the destination of the Depth 2 control then the envelope goes to the control input of the VCA to effect volume.

VCA Envelope:
The VCA envelope is a dedicated envelope for the VCA. The envelope generator is based around the stock x0xb0x/TB-303 circuit. Attack, Decay, Sustain and Release controls have been added. When the controls are in the default positions the VCA envelope is equivalent to the stock x0xb0x. The attack time is variable between 5ms and 1s. Decay is variable between 5ms and 6 seconds. Sustain is variable between 0 % and 100%. Release is variable between 10mS and 6s.

Acc Decay:
This control allows for variable Env Decay times on Accented notes. Usually the stock Filter Envelope has a decay time of 200ms on accented notes. With this control the Decay time can be varied between 200mS and 2s. Accent decay time is independant of normal Env Decay time.

Filter Tracking:
This control determines how much the filter cutoff tracks the note CV. At the minimum setting there is no filter tracking. At max setting there is several times over-tracking. The x0xb0x/TB-303 filter control input has a resting voltage of 3.25v. This means any control voltage below 3.25v will decrease cutoff frequency and any voltage over 3.25v will increase it. Filter tracking is scaled so that this transition happens at note D#1 (2.25v), so as the filter tracking control is increases the cutoff freq will decrease for notes below D#1 and increase for notes above it.

VCO FM (filter mod):
This control determines how much the VCO2 waveform affects the cutoff frequency. At the minimum setting there is no VCO to VCF modulation. At max setting the modulation is extreme.

Hi Res:
This switch increases the max filter resonance. The filter can self oscillate at higher settings of resonance.

Gate On:
This switch turns the gate on indefinitely. This is useful when using the internal sequencer or when playing the x0xb0x from an external keyboard. If you want to keep the gate on and the VCA open indefinitely you can turn this switch on and turn the VCA Sustain control to max. There two modes for Gate on determined by the Env Trigger Mode switch. This has to do with whether subsequent notes will retrigger the stock Filter Envelope and ENV2 when the gate remains open. When this switch is in the ‘down’ position and the Gate On switch is in the ‘on’ position neither the stock Filter Envelope or ENV2 will be retriggered by subsequent notes (while the gate is held open). When the trigger mode switch is in the ‘up’ position ENV2 will be retriggered by subsequent notes but the stock Filter Envelope will not.

Env Trg:
The envelope trigger button triggers the stock Filter Envelope and ENV2 whenever it is pressed.

Slide Time:
This controls varies the slide time between the stock value of ~70ms and 500ms. There is compensation so that the tune remains constant regardless of the setting of the slide time pot.

The Users Manual for the Rear portion of the kit can be downloaded here

Image
Last edited by bcbox on Sat Feb 28, 2009 3:00 am, edited 4 times in total.

booster
 
Posts: 52
Joined: Mon Mar 12, 2007 8:14 am

Re: x0xi0 Full Mod kit Details

Post by booster »

Incredible..........nice work Brian.

Can't wait to get this installed.

Is the panel going to have an adhesive overlay like the IO kit?

bcbox
 
Posts: 587
Joined: Thu May 25, 2006 1:30 am

Re: x0xi0 Full Mod kit Details

Post by bcbox »

yes, right now I'm leaning towards 5mil lexan with 3M 467. After trying several screen printing companies I found one that I like that does an excellent job.

listen202
 
Posts: 25
Joined: Thu Jun 28, 2007 12:04 am

Re: x0xi0 Full Mod kit Details

Post by listen202 »

WOW!
I just saw the post over at http://matrixsynth.blogspot.com/2009/02 ... s-now.html
This is going to be big.
Congratulations and thanks for all your hard work.

karajabola
 
Posts: 32
Joined: Thu Jan 15, 2009 7:20 am

Re: x0xi0 Full Mod kit Details

Post by karajabola »

bcbox wrote:Image
FYI, you have a typo in your layout: "Envelope Geneators"

...just in case that image represents what you'll be sending to print :-)

bcbox
 
Posts: 587
Joined: Thu May 25, 2006 1:30 am

Re: x0xi0 Full Mod kit Details

Post by bcbox »

Thanks for the good eyes!
It's really just a bad mockup, nothing is aligned and fonts are wrong etc.. things have moved around and stuff, the actual label is much more refined.

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