808 kick drum

MIDIfication
1

hi, i have a TR808 and when listening to the kick drum it seems to change volume and decay for every beat, is this normal or do i have aq faulty machine? after running the internal sequencer for 45 minutes the kick drum settles down, however when i trie the Groove Electronics midi retro fit im finding the kick drum jumps around in volume from +7db to -4db whilst triiging the kick drum via midi

2

is the velocity and aftertouch at a constant level in your software?if not it will do the same effect

3

velocity is set to maximum.

4

i wonder if it is possible that the retrokit is taking away voltage from the drum channel?

5

Have you ruled out a bad pot, or an intermittent solder joint? 

6

you mean a bad solder on the retro fit?

7

here is a sample of the 808 kick drum triggered via midi - http://www.pissbass.com/808midikick.wav

8

Why do you need to run the internal sequencer for 45 minutes for the kick to settle down?  What do you mean by “settle down?”  After it settles down, what makes it start acting up again?  If you start the sequencer again, does it take another 45 minutes before it’s usable?

For many people, the groove electronics retrofits are the stuff of myths.  They’re rare, and there is no documentation to be found anywhere.  Does the retrofit kit support dynamics via velocity somehow?  Does this problem only affect your bass drum?

Maybe you’d do well to take some measurements and see what’s happening when the kick settles down.

If the problem only affects the bass drum, you could try switching the lead from the mod board that triggers the bass drum with one you use less often, like one of the toms or something.  See if the problem then goes to the other drum.  If it goes to the other drum, the problem is with the Groove board.  Otherwise, it’s a problem with your 808 kick.

If the problem affects more than your kick, maybe you should be looking at something bigger, like the power supply, or the accent channel (?)

9

hi, could you post an audio file of your kick drum?

10

here is a sample of the 808 kick drum triggered via midi - http://www.pissbass.com/808midikick.wav

Sounds extra funky.  It’s not a bug - it’s a feature!

11

is it?..i got the same behavior on my real 808 and on my clone…this happens when the decay is long.

i posted this some time ago… http://eight-oh-eight.org/phpbb2/viewtopic.php?t=341

but never got any solutions yet.

12

Isn’t this inherent with the 808’s kick design?

It’s like if you had a pendulum standing still.. you tap it, and it’ll rock for a while.. Thats your kick.

Tap it while it’s rocking at any time and it might swing further, or it might swing less.. depending at what point the pendulum is at… so the kick might get louder, or get damped (Quiet / shorter)

Regards

Mike

13

its called self oscillation

14

mmm…yeah i know…the self oscillation thing…but my questions was (on the eight-o-eight-forum) if it would ever be possible to mod the circuit so that it quits it´s “old” oscillation when a new trigger comes in…to avoid such behavior…like the 909 does “resetting” the oscillator (i know this 909 circuit is based on an oscillator which differs compared to the 808 filterswing) …

15

Hi:

I built a TR-9090 (an clone of the TR-909) and played several analog drum machines, and all behaves the same. That’s the cool thing about

analog, if you want a steady repetitive sound go for samples.

16

if you want a steady repetitive sound go for samples.

nahh…dis was nodd de question! :wink: