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Behringer Model D - DIY Mods
Old 24th September 2018
  #61
Quote:
Originally Posted by yeskeys View Post
Amazing thread. I'm primarily interested in the 1volt/octave CV out. Are you guys saying that I could play the Boog over midi, the Boog will play its own oscillators in tune, as well as provide a soldered CV out for simultaneously driving a eurorack oscillator which will play in tune? In my euro rig, I usually have to use a powered mult to distribute a volt/octave pitch CV because a passive mult induces a voltage drop. Just curious if my described scenario actually works. Thanks!
Yep, exactly that.
Old 1st October 2018
  #62
Here for the gear
Thanks so much for the info. My synth is being delivered today. My plan is to do two mods - the midi>CV and later the PWM. I hope to drill holes for 2 new jacks (if there is room) at the top of the front panel. Then, I'll solder a connecting wire from the CV point on the board to the jack tip, and connect another wire from the corresponding ground point to the sleeve. Forgive my elementary questions, I just don't want to mess anything up.
just a few questions if you don't mind:
Do I still need to wire up the ground if the new jack is attached to the metal casing of the front panel?
Also, does the CV out track the effect of the pitch and mod wheels?

Thanks again Maffez!
Old 1st October 2018
  #63
Quote:
Originally Posted by yeskeys View Post
Thanks so much for the info. My synth is being delivered today. My plan is to do two mods - the midi>CV and later the PWM. I hope to drill holes for 2 new jacks (if there is room) at the top of the front panel. Then, I'll solder a connecting wire from the CV point on the board to the jack tip, and connect another wire from the corresponding ground point to the sleeve. Forgive my elementary questions, I just don't want to mess anything up.
just a few questions if you don't mind:
Do I still need to wire up the ground if the new jack is attached to the metal casing of the front panel?
Also, does the CV out track the effect of the pitch and mod wheels?

Thanks again Maffez!
hey, cool & hope you like the D - still digging mine.

> hope to drill holes for 2 new jacks (if there is room) at the top of the front panel.

- might be a bit dense in there, as the pcb is the same size as the panel. using the side panels might be easier and also easier to cover should you want to undo the mods in the future. the wood sides come off easily and the lower part of the sidepanel has enough room as the panel/pcb is quite a bit shallower than the whole case. an alternative would be he bottom of the front panel if you can access that area. hardcore alternative is sacrifice something like the headphones out, but that would require cutting traces on the pcb.

> Then, I'll solder a connecting wire from the CV point on the board to the jack tip, and connect another wire from the corresponding ground point to the sleeve.

- yup. sleeve/ground to case should be enough but to gnd point (you can also use one of the gnd pins of the eurorack connector socket) seems a cleaner job

> Also, does the CV out track the effect of the pitch and mod wheels?
not near the boog this week and honestly cannot remember (ahem...) just had a quick look at the schematics and there pitch cv, bend, modwheel etc are all summed before each VCO, yet remember doing some glide stuff with my dixies... will check when i get back to my music stuff next week or so

-- lemme know how it goes & have fun!
Old 1st October 2018
  #64
Here for the gear
Well, I've had it for about ten minutes now, and wow - Fat as F. Ran a couple euro modulators into it and sounds amazing.
I really hope the Behringer OB thing comes out. I'm totally impressed with the sound of Model D, I've owned all the great major analogs through the years including on orignal D and I'm very impressed with this.
Old 15th October 2018
  #65
Here for the gear
 

hello
thank you for all the useful info in this thread
I am new to the Boog D, but I'll probably modify it too
One thing I do not understand: did you manage to have all six waveforms from one VCO simultaneously ? How can you do that ? I thought it was impossible

Last edited by zaph63; 15th October 2018 at 04:46 PM.. Reason: spelling mistakes
Old 15th October 2018
  #66
Quote:
Originally Posted by zaph63 View Post
hello
thank you for all the useful info in this thread
I am new to the Boog D, but I'll probably modify it too
One thing I do not understand: did you manage to have all six waveforms from one VCO simultaneously ? How can you do that ? I thought it was impossible
Hey, yes, can do. all waveforms are present at the wave select switch, that, in turn, just mechanically switches from input contact to input contact.

vcos work that way that you tap different waves from different parts of the circuit continuously. wave select switches and mixers etc are just surface stuff, as it were. hence, modular vcos, such as the ajh, give you separate wave outs, leaving mix/selection to dedicated modules.

on the moog and the d, square & pwm are slightly different in that that same switch also regulates different fixed pwm inputs to the suqare (think of it as a double switch thing with some pins regulating the vco out to mixer in and the rest for modulation info)

check the labelled pcb for different wave outs

so, if you want to go awol, you can get a total of 18 direct wave outs on the boog
Old 16th October 2018
  #67
Here for the gear
 

hi

sorry to bother you again, but I have to disagree
I still have not opened my BoogD, but I studied the schematic

when you select the triangle wave, a -10V is connected to the "threshold" input of the trigger (T10-T11 for VCO1) so that it should not output any pulse, i.e. the pulse/square pins are silent

when you select one of the pulse/square waves, the output signals on the other two are actually the same

I do not know what the square/pulse pins give when the ramp or shark waves are selected, probably a square, has anyone tried looking this on a scope ?
anyway, they cannot be different from each other, since they are wired together

so in the end you never have six different waves from each VCO, maximum is four, maybe three if you want a clean triangle

I also can not find any reference to the "PWM input" on the selector, as you mention in the pdf document about mods, so I doubt:
... am I looking at the wrong schematic ?
or maybe I missed something, please explain
Old 16th October 2018
  #68
check (on the boog schematics) sw3a, sw11a, and sw21a - the "b" parts of respective switches feed different voltages into the circuit (for tri / saw that's -10v), hence the pwm mod

original model d old osc board schematics also indicate where to tap what at what voltages
Old 16th October 2018
  #69
Quote:
Originally Posted by zaph63 View Post
...all six waveforms from one VCO simultaneously ? How can you do that ? I thought it was impossible
It's quite common for an oscillator in modular to have multiple waveform outputs available...


Just FYI
Old 17th October 2018
  #70
Lives for gear
Quote:
Originally Posted by yeskeys View Post
Thanks so much for the info. My synth is being delivered today. My plan is to do two mods - the midi>CV and later the PWM. I hope to drill holes for 2 new jacks (if there is room) at the top of the front panel.
I was able to install CV out, and post mix level individual oscillator outputs on the front panel. The issue is not so much space on the panel, but room on the board below. Look carefully at the circuit-board and make measurements for exact placement.

I removed the circuit board, and reattached the face-plate to the case to make drilling through the panel easier and safer. These are the only mods I really wanted to do and it's nice being able to fit it all in without a breakout board or needing to rack the boog out of it's case. It's tight, but the boog is tight with it's knob placement anyhow. Not much difference.
Attached Thumbnails
Behringer Model D - DIY Mods-front_panel_mod.jpg  
Old 19th October 2018
  #71
Quote:
Originally Posted by bluegreengold View Post
I was able to install CV out, and post mix level individual oscillator outputs on the front panel. The issue is not so much space on the panel, but room on the board below. Look carefully at the circuit-board and make measurements for exact placement.

I removed the circuit board, and reattached the face-plate to the case to make drilling through the panel easier and safer. These are the only mods I really wanted to do and it's nice being able to fit it all in without a breakout board or needing to rack the boog out of it's case. It's tight, but the boog is tight with it's knob placement anyhow. Not much difference.
Awesome, man! Thought about going directly through the panel too but dismissed that on account of space - great you found some spots to fit sockets in & would love to see pics.
Old 20th October 2018
  #72
Lives for gear
Here is the oscillator section with the breakouts. The stickers are covering up misplaced holes that I tried without carefully inspecting the board and measuring, so don't do that!

I used 3.5MM ENCLOSED SOCKET SKU: A-865 from tayda. I actually tried a couple of other jacks first, but due to space you have to be able to cut the loop extension of the switch jack and bend the loop of the tip to the side and other jacks had metal that was to brittle to bend. The other bonus of these jacks is that they come with washers and the nuts. I used a little tape to insulate the connections (but I should of used the heat shrink I had right there ...). So long as the loop pin is turned sideways for the tip and you trim the jack switch connection you have just enough space to clear.

I like taking the output from the switch as that way you can attenuate the output using the mixer.
Attached Thumbnails
Behringer Model D - DIY Mods-dsc_1014.jpg  

Last edited by bluegreengold; 21st October 2018 at 03:01 PM..
Old 21st October 2018
  #73
Quote:
Originally Posted by bluegreengold View Post
Here is the oscillator section with the breakouts. The stickers are covering up misplaced holes that I dried without carefully inspecting the board and measuring, so don't do that!

I used 3.5MM ENCLOSED SOCKET SKU: A-865 from tayda. I actually tried a couple of other jacks first, but due to space you have to be able to cut the loop extension of the switch jack and bend the loop of the tip to the side and other jacks had metal that was to brittle to bend. The other bonus of these jacks is that they come with washers and the nuts. I used a little tape to insulate the connections (but I should of used the heat shrink I had right there ...). So long as the loop pin is turned sideways for the tip and you trim the jack switch connection you have just enough space to clear.

I like taking the output from the switch as that way you can attenuate the output using the mixer.
Looks total rock ´n´roll, man! This must be frankenbook, serial no 002

Should you grow tired of the stickers, there's metal putty (which doesn't look as cool, however).


Thanks for the info about sockets. I have a couple of those from tayda lying around.

I also think using vco outs post mixer/pre switch is a good option in terms of flexibility.

If anyone knows of micro switches fitting under the panel, let me know, as I'd love to have the sync mod around the oscillator section.
Old 22nd October 2018
  #74
mini update on the cv per vco - found all of the nine 51k1 resistors used for pitch cv summing (keyboard, mod to osc, osc in), now just have to find which is which. the layout is a bit crazy scattered but man, behringer did really maximize space efficiency there
Old 23rd October 2018
  #75
So, I think I almost have the pitch CV per VCO riddle solved.

Will get round to testing it only in a while and might not even implement it since it’s not the most relevant mod for me. Yet, some folks were interested and for completion’s sake etc…

Check the labeled pic of the CV summing and linear/expo conversion sections for the Behringer Model D oscillator section.

Quick explanation:
The upper TL072 sums the pitch CVs of VCO 1 (upper half) and VCO 2 (lower half). The 304 and 4580 are for exponential conversion (again upper half VCO 1 and lower for VCO2). The lower Tl072 is for VCO 33 and both halves of 4580 are used for expo (upper) and Osc Control stuff (the switch with which you can deactivate tracking for Vco 3).

The 51k1 resistors marked green are all relevant/interesting for 1V/octave stuff. Per VCO you have one for Keyboard CV, one for Modbus to VCO, one for Osc Pitch CV in. The blue numbers behind each 51k1 indicates what VCO it’s for. Still need to measure this but makes quite sense in terms of layout and the Minimoog and Boog schematics.

I think for external CV and paraphonic stuff the most feasible mod points would be the three 51k1s for Pitch CV in.

What you’d need to do is test which of these are connected to the pitch CV in socket on the panel (send voltage in and measure the different points; voltage should be the exact same for these three points; wrong 51k1s or the “output side” of the right ones will give you lower voltages). Then desolder the “input side” of these resistors (the guy from the Neutron sync mod vids explains nicely how to do that with smd resistors) so that you break the connection to the CV in socket. Wire the loose ends up with three sockets (tip) and the socket sleeve with ground. Et voila…

Further options would be to put a switch between mod bus and individual VCOs so you could modulate just one – good in combination with the Sync mod

All in all this should do the trick (and is safer/cleaner than the post expo converter stuff suggested in my earlier guide).
Attached Thumbnails
Behringer Model D - DIY Mods-boog_pitch-cv-sum_expo-conversion.jpg  
Old 25th October 2018
  #76
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jurfin's Avatar
I have built a few pedals here and there, but I don't have any experience modifying synths. I'm wondering if it's feasible to add two or three simple passive attenuators to the Model D. Is there room for 6 jacks and three pots on the face, or would those need to go on the sides? Would it be as simple as connecting pots (with the right value of course) to in and out jacks? Would a ground connection even need to be involved for something like this?

I'm thinking it would be nice to have, for instance, a small amount of pitch vibrato and a large amount of cutoff modulation happening at the same time. Or just sending a little of the envelope to the LFO rate, or a small amount of the Mix out to the cutoff. Or all of these things at once! I really enjoy subtle modulation and would love to be able to tone down some of the available options on the D.

Any thoughts on how practical this would be? Is it do-able?

Thanks for your time, and for helping out a noob
Old 26th October 2018
  #77
Quote:
Originally Posted by jurfin View Post
I have built a few pedals here and there, but I don't have any experience modifying synths. I'm wondering if it's feasible to add two or three simple passive attenuators to the Model D. Is there room for 6 jacks and three pots on the face, or would those need to go on the sides? Would it be as simple as connecting pots (with the right value of course) to in and out jacks? Would a ground connection even need to be involved for something like this?

I'm thinking it would be nice to have, for instance, a small amount of pitch vibrato and a large amount of cutoff modulation happening at the same time. Or just sending a little of the envelope to the LFO rate, or a small amount of the Mix out to the cutoff. Or all of these things at once! I really enjoy subtle modulation and would love to be able to tone down some of the available options on the D.

Any thoughts on how practical this would be? Is it do-able?

Thanks for your time, and for helping out a noob
Hey, in principle that's all possible.

As bluegreengold already indicated, there is notr much space for implementing this kind of stuff on the panel directly, but on the sides or lower fronbt of the case no problem. The faceplate annd pcb are by no means as deep as the case.

if you want one mod source going to different destinations you're good with a couple of potis/passive attenuators. you can even easily mix different cvs with a couple of resistors (google/check on muffs for passive mixer). in cases where there might be voltage of several connections or some reverse polarity stuff, putting in diodes might be a good idea.
Old 31st October 2018
  #78
Here for the gear
 

Activating/Deactivating OSC sync without switch

Is it possible to modify the OSC Sync circuit to be possible to activate or deactivate it by 0/5V?
Maybe substituting of diode by transistor + some mods?

Frank
Old 1st November 2018
  #79
Quote:
Originally Posted by macsaif View Post
Is it possible to modify the OSC Sync circuit to be possible to activate or deactivate it by 0/5V?
Maybe substituting of diode by transistor + some mods?

Frank
Never tried something like that but with a logic/switch ic (fet switch maybe?) this should be no problem. supply current for that ic should be positive and +/- 10v max, which you could take from the rails. this would replace the manual switch. diode needs to stay in, I think.
Old 2nd November 2018
  #80
Lives for gear
 

Quote:
Originally Posted by Maffez View Post
hey, dunno if anybody with the tools and cpacity to do faceplates will jump on board, but using multiples in lieu, say manhattan analog 4x4, for instance, might be a workaround. i've slaughtered a doepfer multiple as a brakout for a couple of mod points.

as for cving reso, that's doable (see labelled modpoint pic), contour amount would need more work (an external vca in between the emph pot would do, I reckon) and so would decay length

will keep this in mind tho on account of other stuff this is an on/off thing for me. fiddling on individual note cv for the vcos and possibly filter pole mod atm

I share your frustration, hence my move to start modding. I think Behringer could easily make serious dosh by reissuing a v2 with a patchbay in the manner of the Neutron
Maffez,

Coming back to this thread, was wondering if you ever found a simple gate out? You don't mention it, seems like something that should be rather easy?
Old 2nd November 2018
  #81
Quote:
Originally Posted by Vertflyer View Post
Maffez,

Coming back to this thread, was wondering if you ever found a simple gate out? You don't mention it, seems like something that should be rather easy?
Hey, I haven't because the Mini works with s-trigger, not gate AFAK. Working on corresponding conversion has not been on my priority list, but I'm sure something can be found on moog forums.

Easiest solution is to use the two envelopes or, in lieu of gate proper, the amp adsr with attack & decay set to zero and sustain to full. That's +4.6V only, but workable.
Old 11th November 2018
  #82
Updated modding guide attached, including pitch cv per vco info.
Attached Files
Old 21st November 2018
  #83
Here for the gear
 

rebuild of Boog

I have decided that I will rebuild my Behringer D to analog synth with patch memory. At the moment I am designing the concept. The control and the digital EG+Mod matrix will be solved by Midibox NG and Midibox CV2. My plans are:
1. Add Sub Oscillator to VCO1
2. Add VCO2 and VCO3 SYNC to VCO1 - the switching can be done by reed relays controlled by Midibox NG (is the reed relay good enough to do this job or it should be better to design a circuit with FET?)
3. Waveshape switch will be replaced by relays(4 pieces) or by 4 channel Multiplexer (the relay is the easiest way, do you think is it better to design a multiplexer circuit?)
4. The square pulse width will be controlled continously by CV and also will be added PWM option which could be separately switchable for all 3 VCOs
5.The octave switches and fine tune pots will be processed by the Midibox CV2 and for all 3 oscillators I will have a separate CV out. This CV outs will be affected by the digital mod matrix too
6. I am planning to add a second Ladder filter with selectable poles from 6-24 and assymetrical overdrive.
7. The 2 Ladder filters could be used paralelly or serial
8. Mixer section volume control should be regulated by LM13700
9. I am planning to replace EG circuits by Midibox CV2
10. THe existing MOD circuit should be splitted for separate circuit where the VCO3 will be the source and routed to VCF and or VCO1 and 2 + Pitch correction CV (correcting of pitch shift caused by FM), the existing analog LFO will be controlled by more sources (Modwheel, AT, Mod button, Midi, etc) and should be routed to VCF, VCO1-3)
11. To the output I will connect my effect pedal Zoom MS70CDR
And many other small mods. I know that it is too much but I think it is not impossible
The first step will be to make the hardware (case, keyboard) than make the digital control circuits (Midibox NG, Midibox CV2) than finally I will design and test the PCB which will be placed above the existing analog board (existing switches and pots removed and rewired to the board above). Soon I will post my idea about the architecture.
At the moment my first question is wether is better to use reed relays to substitute the existing switches or is it better to design analog switch and multiplexer circuits? I think using of reed relays could make the work easier but for long time maybe the analog switches should be better solution!
I have attached the work version of the drawing of the chassis.
Frank
Attached Files
File Type: pdf Miniboog.pdf (45.9 KB, 158 views)
Old 21st November 2018
  #84
Quote:
Originally Posted by macsaif View Post
I have decided that I will rebuild my Behringer D to analog synth with patch memory. At the moment I am designing the concept. The control and the digital EG+Mod matrix will be solved by Midibox NG and Midibox CV2. My plans are:
1. Add Sub Oscillator to VCO1
2. Add VCO2 and VCO3 SYNC to VCO1 - the switching can be done by reed relays controlled by Midibox NG (is the reed relay good enough to do this job or it should be better to design a circuit with FET?)
3. Waveshape switch will be replaced by relays(4 pieces) or by 4 channel Multiplexer (the relay is the easiest way, do you think is it better to design a multiplexer circuit?)
4. The square pulse width will be controlled continously by CV and also will be added PWM option which could be separately switchable for all 3 VCOs
5.The octave switches and fine tune pots will be processed by the Midibox CV2 and for all 3 oscillators I will have a separate CV out. This CV outs will be affected by the digital mod matrix too
6. I am planning to add a second Ladder filter with selectable poles from 6-24 and assymetrical overdrive.
7. The 2 Ladder filters could be used paralelly or serial
8. Mixer section volume control should be regulated by LM13700
9. I am planning to replace EG circuits by Midibox CV2
10. THe existing MOD circuit should be splitted for separate circuit where the VCO3 will be the source and routed to VCF and or VCO1 and 2 + Pitch correction CV (correcting of pitch shift caused by FM), the existing analog LFO will be controlled by more sources (Modwheel, AT, Mod button, Midi, etc) and should be routed to VCF, VCO1-3)
11. To the output I will connect my effect pedal Zoom MS70CDR
And many other small mods. I know that it is too much but I think it is not impossible
The first step will be to make the hardware (case, keyboard) than make the digital control circuits (Midibox NG, Midibox CV2) than finally I will design and test the PCB which will be placed above the existing analog board (existing switches and pots removed and rewired to the board above). Soon I will post my idea about the architecture.
At the moment my first question is wether is better to use reed relays to substitute the existing switches or is it better to design analog switch and multiplexer circuits? I think using of reed relays could make the work easier but for long time maybe the analog switches should be better solution!
I have attached the work version of the drawing of the chassis.
Frank
Holy cheesecake, Frank, this is some ambitious and compelling plan! Cassis also looks awesome (need to go through it in more detail but at first glance that's A+)

Right, maybe others want to chime in as well/my electronics ken is limited, so I can give you only some off the cuff estimations, but as soon as time allows am willing to read up.

for 2.: reed should be good enough I think, but not sure about their lengevity; the only contact I had with them was in my dad in law's ancient organ and some of them had become brittle, but that was old Wersi stuff... how about using something like a 4066 - gives you 4 switches in one IC

for 3.: I'd go for multiplexer on account of having less parts (one IC rather than several reeds)

yet, as for both, if reed is easier and a bigger case provides you with more space, why not?

4 & 5 great! guinguin's MME offers PWM on all VCO's and that's just cool

10 cool but maybe no need to split the circuit. routing vco 3 separately could also be done by vco direct out and feeding this into existing cv ins (resp. additional vco 1/2 ins). this would mean patching rather than total recall, of course

This as some first thoughts. And again, wow, big plans & fingers crossed!
Old 26th November 2018
  #85
Here for the gear
 

I know it is too much but I think it is not impossible. As a control surface the Midibox should work, just finished my dual manual organ controller including 39 potentiometers + 48 buttons + Leds + 256 position pantch memory. The woodwork is partially finished, just I have to stick the frame together + paint. I have started to design the steel cabinet for electronics. Also I am working on the main architecture to see on paper which parts can I use from the original Behringer and which new parts has to be designed. I think, this year should be ready the chassis and the main architecture, then next year will start to design step by step the new parts. If I have any news, I will post it here.

Frank
Old 27th November 2018
  #86
Quote:
Originally Posted by macsaif View Post
If I have any news, I will post it here.

Frank
cool & do so, please! intriguing project
Old 20th December 2018
  #87
Here for the gear
 

Great thread; thanks mucho Maffez. I hope someone figures out how to implement pitch cv and reports back. It would be so cool to be able to send three-note chords to the Boog from Pressure Points.
Old 20th December 2018
  #88
Here for the gear
 

The actual status is, that the housing is ready for painting. Unfortunately I can continue only in January.
Frank
Attached Thumbnails
Behringer Model D - DIY Mods-img_20181220_205820.jpg  
Old 22nd December 2018
  #89
Quote:
Originally Posted by electricanada View Post
Great thread; thanks mucho Maffez. I hope someone figures out how to implement pitch cv and reports back. It would be so cool to be able to send three-note chords to the Boog from Pressure Points.
thx - pitch cv is just a matter of time...
Old 22nd December 2018
  #90
Quote:
Originally Posted by macsaif View Post
The actual status is, that the housing is ready for painting. Unfortunately I can continue only in January.
Frank
sweet!
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