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All Yocto Mods

PostPosted: Dec 22nd, '13, 12:26
by e-licktronic

Re: All Yocto Mods

PostPosted: Mar 4th, '14, 12:25
by misa

Re: All Yocto Mods

PostPosted: Apr 28th, '14, 12:58
by pistrix
Its surprisingly quiet here in the mods section. Has anyone else been experimenting?

Here are the ones I've done (& recommend fully!), most from http://xlargex.xl.funpic.de/ (which seems to be offline/gone at the moment..):

BassDrum Endless/Extended Decay -- replaced R170 (470k) with 370k resistor in series with a 100k potentiometer. then i set the potentiometer to the 'sweet spot', where the extra decay sounded best to me, and measured the resistance of the 370k resistor plus the resistance of the potentiometer setting. on my Yocto, 445k was the nicest value for self-oscillating/extreme decay ;). then i removed the 370k resistor and potentiometer from R170, and finally replaced R170 with an SPDT switch that selects between a 470k resistor (the original value/normal setting) and 445k (the 'sweet spot' for extra decay i measured, using a few resistors to achieve the 445k value).

BassDrum Tuning -- replaced R165 (47k) with SPDT switch that selects between original value (47k) and a 100k potentiometer (audio/log preferably)

BassDrum Tuning Envelope -- replaced R166 (6.8k) with SPDT switch that selects between original value (6.8k) and a 5k potentiometer in series with a 2k resistor. (in combination with the tuning mod, this mod enables some nice extra-punchy bass drums!)

Clap Noise Offset -- replaced the 10k trimpot in the clap section with 10k potentiometer..

Closed Hihat filter -- replaced R147* (2.7k) with an SPDT switch that selects between original value (2.7k) and a 10k potentiometer in series with a 1k resistor

Open Hihat filter -- replaced R153* (2.7k) with an SPDT switch that selects between original value (2.7k) and a 10k potentiometer in series with a 1k resistor

Re: All Yocto Mods

PostPosted: Apr 28th, '14, 13:01
by pistrix
these attempts to translate & implement some of the mods found on other sites were unsuccessful, I wonder if anybody has some insight? i suspect the clap mods don't work because they were designed for BA662 not BA6110..

Snare Low Tune -- based on the instructions from multiple sites, it seems like replacing the 820k resistor in the snare section (R197) with a 1M potentiometer + 220k resistor in series should do the trick, but alas, it has no effect on my Yocto..

Rimshot/Clave tuning -- attempted translation from the MB-808 mods, i replaced R312 (1k) with a 10k potentiometer in series with a 200 ohm resistor. it seems to work, but it just doesn't sound very good/usable, the adjustment area is much too wide. maybe something like a 1k pot in series with 9k resistor would work better..

Clap Reverb Decay -- attempted translation from the MB-808 mods. replaced C138 (47nf) with an SPDT switch that selects between original value (47nf) or 100nf (extra long decay). it seems like it almost works, but not quite..

Clap Bandpass -- attempted translation from the MB-808 mods. replaced R333 (10k) with an SPDT switch that selects between original value (10k) or 50k potentiometer with 1k resistor in series. almost works, but not quite..

Re: All Yocto Mods

PostPosted: Apr 28th, '14, 13:26
by pistrix
PS -- it took some digging to find documentation for the MB-808 project, especially the crucial 'part names' files...a lot of searching internet archives like Wayback Machine.

i uploaded the useful files i found to: http://www.sendspace.com/file/qndn3k

hopefully someone else finds them useful too

Re: All Yocto Mods

PostPosted: May 27th, '14, 02:33
by zmb
Thanks for the info! For the moment I'm just building it straight but I'm hoping to incorporate some of these same modifications into my final build. Especially the bass drum modifications. I've built the individual instruments on breadboard in the past and found some very nice mods for the BD but I'm not sure how to translate them, especially since it seems like the PCB design doesn't leave much room for extra front-panel knobs or buttons.

Re: All Yocto Mods

PostPosted: Jun 8th, '14, 14:06
by krisbo
I've also don't the bass tune/envelope mod and the hat filter mods. Works great. I've installed switches and potentiometers on the back panel to control them and give me the option to switch back to the original value.

I've also upped my toms noise resistors from 15K to 56K to reduce the amount of noise. I've mentioned it on another thread but I'll mention it here too:

Hi tom noise level = R273
Middle tom noise level = R245
Low Tom noise level = R216

Re: All Yocto Mods

PostPosted: Dec 14th, '14, 23:40
by metel909
i found one web-site for the TR-808 Mod :o :o :o

http://meta-design.biz/808.html

does anyone know which turn on/off switch value and pot ?

Re: All Yocto Mods

PostPosted: Feb 13th, '15, 15:19
by arnarmarol
Is it possible to change a resistor value to simply lower the fixed pitch of the BD?

Re: All Yocto Mods

PostPosted: Feb 14th, '15, 01:44
by zmb
arnarmarol wrote:Is it possible to change a resistor value to simply lower the fixed pitch of the BD?


Yeah I haven't pulled up the schematics but basing it on the post higher up

"BassDrum Tuning -- replaced R165 (47k) with SPDT switch that selects between original value (47k) and a 100k potentiometer (audio/log preferably)"

If you replace that resistor R165 with a different resistor (instead of a switch+pot as suggested) you should get a different fixed pitch.