e-licktronic Forum

I know I'm late, anyways...

I have two questions regarding the phasing between snare and handclap as mentioned (and solved) in this thread:
viewtopic.php?f=26&t=837&hilit=phasing+snare+clap

1. Was this present in the original TR909? Studying the schematic I would guess yess but since Nava uses BA6110 instead of BA662 maybe not?

However there are reports that phase inverting clap separate out helps so maybe...?

2. According to the Nava schematic, IC28B is unused and therefore free to use. Could this be used as an inverter or something like that to solve the problem? But I guess the phase difference is not exactly 180° so maybe not?

OK, sorry. I missed this thread earlier, the "problem" was present in the original 909-design:
https://www.gearslutz.com/board/electro ... blems.html

It would be interesting to know if there where any revs where this might have been solved though...

Oortone wrote:It would be interesting to know if there where any revs where this might have been solved though...

Some people have addressed this design flaw/choice (depending on how you look at Rolands original implementation) by adding an additional noise circuit to the Nava.

See viewtopic.php?f=26&t=837 for further info.

m4d wrote:

Oortone wrote:It would be interesting to know if there where any revs where this might have been solved though...

Some people have addressed this design flaw/choice (depending on how you look at Rolands original implementation) by adding an additional noise circuit to the Nava.

See viewtopic.php?f=26&t=837 for further info.

Yes, thanks for the info.

I tested separate out SD/HC in my daw and phase reversing one removes phasing. So this indicates 180° phase shift. If the free half of the IC suggested can be used to invert the signal, then that would fix it and no secondary noise source would be needed.

However, since this is present in the real 909 and it can be fixed easliy in a DAW I will not mod this.

Hey, nice idea !

I think this was me you read saying that inverting phase pretty much remove phasing..? In theory this shouldn't really remove it, because there is still something in common between the two signals. This was only a sort of experimental things to show a quick solution if there's nothing else under the hand... but maybe this is enough good ! This is a long time since I tried it so I'm not sure how much this sounds OK.

gihaume wrote:Hey, nice idea !

I think this was me you read saying that inverting phase pretty much remove phasing..? In theory this shouldn't really remove it, because there is still something in common between the two signals. This was only a sort of experimental things to show a quick solution if there's nothing else under the hand... but maybe this is enough good ! This is a long time since I tried it so I'm not sure how much this sounds OK.

I actually tried to see in the waveforms how much the signal is shifted but that as impossible to see. To big difference in other aspects.

If one signal is aprox 180° shifted then that's the most likely reason for the phasing and then reversing one is the best solution. In the 808 there are also parallell noise but no phasing so it's possible to get clean sound using this tecnique.

However it might be that it's not exactly shifted 180° but reversing gets a cleaner sound anyway. Hard to tell.

(I quess it's incorrect to say 180° shift when talking about noise, reverse polarity might be a better expression?)