Do I need an AOUT for my MB9090 or not?

[pcbatterij]

hey all,

I am trying to build a MB9090 (I still have a few hum problems but I am pushing through with the build).

I have finished the 9090 part and I am going to build a MB808-ish sequencer for it. But something puzzles me: how is it possible that the MB808 is working without a AOUT for the velocity of the voices?

I have noticed that microlarge uses an AOUT for the voices.

Did I miss something, or am I just stupid?

I thought I needed the following:

core STM32 or LPC17

a few DOUT's for LED's, BPM led's and a 2*16 LCD

a few DIN's for the buttons and only two or three encoders

AND an AOUT for the CV output.

Cheers

Jef

http://www.bloggen.be/mb9090/

[Altitude]

you shouldnt need it. Why not just run it over midi?

Edited August 29, 2011 by Altitude

[Nasrudin]

i just have taken a small view over the 9090 schematics - i couldnt see a single control voltage input.

since this project has a fully featured midi interface there is no need for such a relict ;-)

Sincerly,

Nasrudin

[nuke]

i thinks it´s all about the timing...while midi is serial, triggering analogstyle like the 808 is more timingprecise...

you should consider that the accent is different on those machines...while the 808 has a global-accent which is triggered by a little pulse (1ms) on the steps going from 5-15V, using the accent-pot to vari these value...5V is constant, the pulse on the steps triggers an "accentuator" to punch in.

microlarge used the aout to seperate the "global-accent" and drive the instrument-accent via midi then. if you look closer they are not all with it´s own velocity-aout.

the 909 has a different accent. they each (intruments) have their own accent-line when looking at the schematics.

but the accents aren´t driven by a single pulse-click, it´s more a constant value which stays until a new value is given.

if you try to drive this with the 808 accent on the mb808 you will get nasty clicks and not the accent-behaviour like you wish.

so you would need an own accent-track for each drumpart what means changing in code ( if it would be possible...dunno much about coding ;) )

but what will work in the mb808seq is clamping each 909 accent to +V to make them trigger (you can even leave the dedicated opamp out, since it´s tripling the 5+ to ca. max 15V ), but then you loose the accent completly...

i did this on my 909BD and 909LT which i put in my mb808 spare tracks, they work but without accent.

if i´m wrong , feel free to correct me... :rolleyes:

otherwise sm:)e , nik

[nuke]

...ooops doublepost

Edited August 29, 2011 by nuke

[nebula]

The TR-808 doesn't have dynamic voices. There is a global accent and that's it.

The TR-909 is different, in that its built-in sequencer offers two dynamic levels for most sounds, in addition to a global accent, plus it offers more dynamic control if controlled by MIDI.

I have been casually trying to figure out the best way to do this for the 9090 as well. My 9090 boards are about halfway finished, and once they're done I plan to investigate this a little further. I also would like to have a MIDIbox sequencer controlling the 9090. I'm going to bet that the best way would be to use the DAC on the 9090 board (created with a resistor array).

Unfortunately the MIDIbox 808 sequencer at this time AFAIK does not offer any way to program different dynamics for each note. So this will probably involve modifying the MIDIbox 808 firmware, or using MB SEQ (I don't want to do this).

As for those who suggest that MIDI control of the 9090 is better, I have to agree with nuke that a standalone drum machine ultimately should not be subject to the timing limitations of MIDI when played from its own sequencer. It's not a big deal when only playing an individual part, but if you have a place where, say, 5 sounds occur at the same time, you will necessarily have an audible flam as the notes must be serialized with a best-case 1 ms gap between notes.

[taximan]

Hiya,

I'm not going to pretend I know everything you guys talk about but I am interested in this post as I also have a 9090 about 80% finished.

It was my intention to build in the beat 707 (arduino and beat 707 shield) into the finished unit but on reflection I may as well run the beat 707

separately,this leaves the 9090 as it was intended and I get to keep my sequencer should I ever want to sell the 9090.

I don't understand the comments about the 1ms delay on multiple notes though,I use my yamaha dd55 with the sticks to drive my alesis sr16 sometimes via midi

and can't say I have ever noticed the notes 'stuttering?' as such.

Not trying to be a smart ass....just interested and a little puzzled.

cheers

Paul