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-5 to +5 octave and semitone switching board any interest ?
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roglok



Joined: Aug 28, 2010
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PostPosted: Tue Jul 31, 2012 1:41 am    Post subject: Reply with quote  Mark this post and the followings unread

btw., I can totally recommend the above mentioned NKK switches. Well worth the extra money...
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diablojoy



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PostPosted: Tue Jul 31, 2012 3:00 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
To be honest, I only want to use the positive 5V offset part and keep both coarse and fine controls. So basically I want to add an extra CV input without sacrificing any of the existing ones. Is there a maximum number of inputs one can add to the summing node?

An odd choice Confused for me as far as VCO's go the main point was to replace the coarse and fine pots with something that was more accurate to set and patches could be made far more repeatable. I cant see any advantage in what you are planning , perhaps i am missing something ?
as far as max number of inputs to the summing node goes
I dont know that there is a maximum number, adding one more would be fine i would think.
with only the positive octaves being required you would only need to stuff a quarter of the new board,.... maybe.
boards should work out small and cheap at least anyways
managed to get the board size down to 72 x 49 mm last night
think i can still shrink it some more though.
cheers

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roglok



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PostPosted: Wed Aug 01, 2012 3:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

I reconsidered this. And in fact you are right. The reason I planned on adding this simple octave switcher was that I have some space left on my 4046 panel. My idea was simply to add more performance controls to the VCO. On my Roland MC-202 I often use the range switch to change octaves on the fly while a sequence is playing.

But I realised that this would probably make it harder to tune or at least require careful matching of the CV summing resistors as well... Not really worth the hassle...

I know this is OT, but do you maybe have an idea what feature I could add instead? Very Happy


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diablojoy



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PostPosted: Wed Aug 01, 2012 4:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

For me personally i would go octave sw , semitone sw and a fine detune
pot across the top row
however you could also use that first position for an attenuverting
input for some extra modulation possibilities,edit : but that would require an extra jack just came to mind as i had just looked at foniks new single attenuvertor he is planning to do

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diablojoy



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PostPosted: Tue Aug 07, 2012 2:57 am    Post subject: Reply with quote  Mark this post and the followings unread

bit of a struggle with eagle but finally beat it into submission and am now happy with the new layout so off to the fab house for the files
hopefully get some prototype boards back in a couple of weeks Smile
they might even just work Surprised touch wood

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aladan



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PostPosted: Tue Aug 07, 2012 3:32 am    Post subject: Reply with quote  Mark this post and the followings unread

diablojoy wrote:
bit of a struggle with eagle but finally beat it into submission and am now happy with the new layout so off to the fab house for the files
hopefully get some prototype boards back in a couple of weeks Smile
they might even just work Surprised touch wood


Good news! I am about to do a bunch of panels and would like to incorporate some of the new boards.

Cheers,
A.
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diablojoy



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PostPosted: Wed Aug 08, 2012 12:43 am    Post subject: Reply with quote  Mark this post and the followings unread

pic of the new board layout
size is approx 72 x 46 mm


octave and semitone switch new design rev 4.pdf
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 Filename:  octave and semitone switch new design rev 4.pdf
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diablojoy



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PostPosted: Wed Aug 08, 2012 1:15 am    Post subject: Reply with quote  Mark this post and the followings unread

Next i think i will be doing a panel control board for this
2 x the smaller NKK type switches and a 9 or 16mm alpha vertical pcb mount pot so I can get down to 1 inch spacing and if i use a 30 pin 2.54 mm dual row pcb mount socket the octave and semitone board should just plug in to it only power and jacks would need wiring then

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Osal



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PostPosted: Wed Aug 08, 2012 1:57 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello diablojoy , Looking at schematics in page 1 and this last PCB layout I recommend:

1- Solder the voltage divider's resistors directly in the rotary switch. This simplify the PCB layout a lot but more important it simplifies the front panel wiring. You just need three cables from the PCB to the each rotary switch.

2-Ground the 0V in the voltage divider. This reduces the worst case error of the voltage divider. And it is only one extra cable for all the rotaries switches.

3-Put the 1K output resistor inside the feedback of the op-amp. Ideal CV has output impedance 0.

Ill upload today in my site the schematics of a stepwise control voltage idea I had time ago that I just revised.

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diablojoy



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PostPosted: Wed Aug 08, 2012 2:18 am    Post subject: Reply with quote  Mark this post and the followings unread

schematic
Hi Osal good input thankyou

1 . hopefully beyond CV jacks the front panel wiring will soon be eliminated
again by direct board to board connection with a panel control board
trying to acheive a 1" vertical and horizontal spacing between controls

2 . see new scheme attached

3 . have not seen that done before sounds interesting
not sure how i would implement that with the new scheme as i have added a summed output as well as the individuals any hints most welcome Smile
always makes my day to learn something new.


octave and semitone switch new design scheme rev 4.pdf
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Osal



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PostPosted: Wed Aug 08, 2012 2:52 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Diablojoy I will study your schematic later.
Here is mine:
http://electronic-sea.net/stepwise_control_voltage.html

Ah! however you finally design this module I'm interested in one PCB at least. Very useful module.

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Osal



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PostPosted: Thu Aug 09, 2012 8:45 am    Post subject: Reply with quote  Mark this post and the followings unread

diablojoy wrote:
schematic
Hi Osal good input thankyou

1 . hopefully beyond CV jacks the front panel wiring will soon be eliminated
again by direct board to board connection with a panel control board
trying to acheive a 1" vertical and horizontal spacing between controls


This is what i suggested which simplifies further the layout:
http://electronic-sea.net/pictures/modules/stepwise_control_voltage/rotary_switch_voltage_divider.png

Quote:
2 . see new scheme attached

Yes this is what i meant.

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diablojoy



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PostPosted: Thu Aug 09, 2012 3:12 pm    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
This is what i suggested which simplifies further the layout:
http://electronic-sea.net/pictures/modules/stepwise_control_voltage/rotary_switch_voltage_divider.png

yes i actually did it that way with the very first board i did which was single sided and self etched and electronically it does make sense however some people find such component mounting very fiddly and dislike the look from an aesthetic point of view
at worst with the new board it will mean a ribbon cable which can be made to look quite neat. At best it will just be a matter of plugging it directly into another PCB for the panel controls which i am about to start drawing up just waiting on some switches from Allied for those that like their controls on 1" spacings. now i could have still left off the resistors and put them on
the panel control board or on the switches themselves which would have been far easier for me but i preferred to go the way i have to make it easier for others to build.
I have 8 prototype boards being manufactured at the moment, this is mainly to prove the board layout but i will probably use these in a planned matrix sequencer build for myself that is if they work of course Laughing

I guess i should reiterate here i have no real interest in selling boards myself, i have too little time for it now, Originally 3 years ago was a far different time. So for the moment at least i simply plan to release the schematic and the gerber files so that others here can have boards made for themselves or do their own layout from the schematic if they wish to do so. If there were to be a massive surge of interest Shocked Laughing i might be tempted to change my mind on that but i honestly think that is highly unlikely.

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sonicwarrior



Joined: Dec 22, 2005
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PostPosted: Tue Dec 11, 2012 9:14 am    Post subject: Reply with quote  Mark this post and the followings unread

It looks like some people @Muffwiggler are interested in a compact octave switching PCB:
http://www.muffwiggler.com/forum/post-1011480.html#1011480
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diablojoy



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PostPosted: Tue Dec 11, 2012 6:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

ah yes , so i see thanks
I have been sidetracked of late away from working on this design
however it is progressing slowly but surely
the main board is finalised and working, just need to order a new prototype and retest as there was a kludge and the silk screen had issues, which i would like to correct still to do the panel board but time and finances have been a bit stretched for the last few months due to a dodgy employer [I am still owed money which i will now probably never see ]
should have something out in Feb maybe i hope.

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emdot_ambient



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PostPosted: Thu Dec 13, 2012 3:12 pm    Post subject: Reply with quote  Mark this post and the followings unread

I keep thinking about octave switching like this (and have the YuSynth standards module to build), but I don't particularly like the rotary switch method because it doesn't give you random access to the various transpositions...You can't go from -1 Oct to +3 Oct in one go, but have to swtich up 4 times to get there.

What I'd really like to see in my VCOs is just 2 switches:
1 Oct, 2 Oct (an On / Off / On so that 0V could be selected)
Transpose Up, Transpose Down (basically a non-inverted / inverted switch)

With a quick flip of the switches you could instantly select between -2V, -1V, 0V, +1V and +2V transpositions.

Semitone switching isn't too important to me, although I do like the idea of semitone switchs with a very fine tune pot (plus or minus something less than one semitone).

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diablojoy



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PostPosted: Thu Dec 13, 2012 5:58 pm    Post subject: Reply with quote  Mark this post and the followings unread

hmm yes i can see there may be times where that would be useful
and indeed that could be done easily enough with what i am drawing up
as the main and panel control boards are to be seperate
you could just select the required taps out and back in of the main board and use those
you would still need to fill out the components for the entire +/- octave section but wouldnt need to completely stuff the rest of the board if the semitones are not required and a panel control board in that case would not be needed at all obviously.

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isak



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PostPosted: Fri Dec 14, 2012 11:12 am    Post subject: Reply with quote  Mark this post and the followings unread

I personally think that fine pot is very important cause in my music I use a lot of ethnical "leads" so the tones in between are good to my music.
Like playing on Violin, no limits, no bounderis.

Cool project man Smile

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