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Circuitbenders Forum => Drum machines => Circuitbending discussion => circuitbenders.co.uk CB55 - DIY Boss DR55. => Topic started by: Barcode on July 30, 2014, 12:07:01 AM

Title: CB55 Mods *Updated*
Post by: Barcode on July 30, 2014, 12:07:01 AM
This is my first post on the forums. Thanks for having me.

Here is a list of mods that I found for the CB55. The how-to's for the Bass Drum Pitch and Decay mods can easily be found on the web but the others are listed but how-to's are no where to be found. Here is what I've come up with so far. I do not have the CB55 PCB yet so none of these have been tested yet and pot values have yet to be determined...

Individual Voice Level - Rather than jumpers use pots between J3, J4, J5, and J6. Also, I personally plan on using switching jacks for the individual voice outs. When nothing is plugged into the individual out the drum voice will be part of the main mix out. Use a 10KA pot for each.

Bass Drum Decay - Replace R33 with a 1KB Pot and 500R trimmer

Bass Drum Pitch - Replace R31 with a 1MB Pot and 2M trimmer

Snare Drum Pitch - Replace R50 with a 1MB Pot and 2M trimmer

Snare Drum Noise Level - Replace R57 with a 10KB Pot (This mod will only slightly change the noise level going to the snare drum. I will continue to experiment and report back)

Rimshot Pitch - Replace R43 with a 1MB Pot and 2M trimmer

I will keep this list updated as I find changes or if other folks make posts.
Title: Re: CB55 Mods
Post by: Circuitbenders on August 01, 2014, 07:19:22 PM
Check out the outputs thread, as the snare and hats outputs aren't as easy as just wiring outputs to where J3 and J4 should be. You have to account for the annoying snare and hat submix that goes straight to the main mix out via R61, R72 and J7 etc. Otherwise the sounds aren't removed from the main mix when you plug in a jack, and they bleed onto each others individual outputs.

http://www.circuitbenders.co.uk/forum/index.php/topic,2419.0.html (http://www.circuitbenders.co.uk/forum/index.php/topic,2419.0.html)
Title: Re: CB55 Mods *Updated*
Post by: Barcode on October 01, 2014, 10:10:27 PM
I'm finally getting around to posting the mods. After doing some testing I limited the amount down to mods I found to be really useful. The first post has been updated.
Title: Re: CB55 Mods *Updated*
Post by: aerror on October 06, 2014, 01:37:34 AM
thanks a lot @barcode
Title: Re: CB55 Mods *Updated*
Post by: gert on March 03, 2015, 08:14:19 AM
hey @all, i am the new one here.

i just finished my dr-55 clone board and had lots of fun with it, so now i would also be interested in adding some mods. i found some informations on the interwebs which seem to be missing here, could we possibly merge this all into one huge information source for the mods? i will try them out the following days to confirm what really works. anyone possibly have an idea which resistor defines hihat pitch? thats the only one i miss for now, i did not look into the circuit too much yet. thanks for helping!
Title: Re: CB55 Mods *Updated*
Post by: gert on March 26, 2015, 08:15:31 AM
finally came around to finalize and integrate my mods.

lots of wires... luckily they do not affect eachother noticeably, midi to trig is done with a cheap "deek robot" board and some simple code (had someone help me with that, maybe i can post the code if someone is interested):
(http://oi62.tinypic.com/2n7lc3t.jpg)

closed case, i went with a polycarbonate hammond but coated the inside with copper tape for better shielding, it fits the board, trigger converter, pots and connectors quite well, not much space left though:
(http://oi59.tinypic.com/8y6l8o.jpg)

and the mod point and pot value details, i used only little information for the usual points and tried to find some of my own. when two wires are attached the pot replaces the resistor, for snappy decay you need two wires, other values just put the pot against ground, so you can run one ground wire to the pots and minimize wiring effort:
(http://oi59.tinypic.com/14m7vvs.jpg)

(http://oi61.tinypic.com/f398ip.jpg)

(http://oi62.tinypic.com/8ytfer.jpg)


i also came up with a closed/open hihat circuit idea which sounds quite good to me, i may post a sound demo soon.

one problem i noticed, and i think it is not because of my mods - the snare sounds a little different sometimes, the "snappy" is varied a bit and sometimes the body pitch changes slightly. it is more than the usual "analog variation" you have in drums, anybody experienced this behaviour yet?
Title: Re: CB55 Mods *Updated*
Post by: Circuitbenders on March 26, 2015, 05:47:28 PM
Somebody give that man some kind of prize!  ;D

Any chance of a some audio?
Title: Re: CB55 Mods *Updated*
Post by: gert on March 28, 2015, 02:35:10 PM
thank you. i tried the kit in my larger setup yesterday and it sounds really great, i hope to record it maybe today. also the snare problem is not noticeable in the mix, its maybe a phenomenon you hear when you listen to two hours of plain snare hits while trying to modify the board ;)
Title: Re: CB55 Mods *Updated*
Post by: gert on April 10, 2015, 09:10:04 PM
so, i finally found time to record things: https://soundcloud.com/zerozillion/circuitbenderscouk-boss-dr-55-clone-modified


it was quite hard to find the right recording volume to get all the louder sounds, watch the volume knob!
Title: Re: CB55 Mods *Updated*
Post by: rempesm on April 12, 2015, 12:04:40 PM
Hi Gert,

Thanks for sharing all these goodies.  That's some awesome flexibility you've managed to pull out of the board.

I'm just finishing up the standard build but I think I'll definitely need to add in those mods.

A few points of curiosity:

Did you happen to find any other mods for Rimshot outside of Volume in your travels?

I was originally planning on using a modded TR505 with trig outs for this but I would be curious to see the code you used to do midi to trig as I'm not certain if I'm going to be able to get the closed hi-hat mod working otherwise.  As far as I can tell the TR505 has trigger durations all over the place which necessitates using the trigger conditioning circuitry.  Unfortunately I'd have no idea how to setup a similar conditioning circuit that's already on the board which would spit out 5ms trig instead of 10ms trig.

Lastly, I can't really tell from the photo but do you have anything hooked up to those momentary buttons or do you have any plans for them?
Title: Re: CB55 Mods *Updated*
Post by: gert on April 12, 2015, 02:21:38 PM
you're welcome!

i found the rimshot so nice on it's own, as it cuts the mix perfectly in my usage, that i did not want to mod it in any way. but it is basically easy, just poke around on the resistors, put a smaller resistor in parallel and listen to what happens. if you found a "good spot", desolder the resistor and put a pot there (it's good to have several values to try). if you find a better spot later, solder back the resistor and put the pot to the other place. sometimes a pot in parallel to a cap can change timing or timbre aswell, i only understood a few core principles when i did the mods and basically just poked around until i got it right for my needs, and this was over a course of two weeks in my free time. so no instant results, it takes a while to get it done properly.

i just emailed the guy that helped me with the code, if i may post it here. for my needs i set it up on midi channel 10, and it responds to typical general midi note numbers, 12 triggers all in all.

yes right, the closed hi-hat would need a proper short impulse but there is no conditioning circuitry left, for me it was easy to do with the trigger board. i also heard that the TR505 triggers are really not much "normed".

possibly you can use a 555 and a fairly small capacitor to condition the trigger? http://www.learnabout-electronics.org/Oscillators/osc45.php (http://www.learnabout-electronics.org/Oscillators/osc45.php)  i saw some simple solutions once in a Facebook discussion, but cannot find any now on google.

the 4 momentary buttons were meant to trigger the sounds in standalone mode, but until now i was too lazy to integrate diodes in the arduino trigger lines to run these together to the cb-55 trigger inputs. mostly when you use it you will hook it up to midi anyways, so you hear instant results.
Title: Re: CB55 Mods *Updated*
Post by: gert on April 16, 2015, 12:09:57 AM
An update: Possibly for the BD and SD reso potentiometers a logarithmic (A) one would work better, as the tweaking range until 3 o'clock is doing only subtle changes and after 3 the reso hits in quite fast, the distance to set it properly is just a few millimeters. Iirc i would have taken log right from the start, but in my stock are only chinese log pots with a 24 step raster...

For the trigger board, as mentioned in the CF thread: I did only test this with a dedicated Note on/off sequencer, i will once fire midi clock, MMC/MTC at it to see how it performs in these situations.
Title: Re: CB55 Mods *Updated*
Post by: 01012k7 on June 03, 2015, 06:34:52 PM
I am atb the moment building another 4 boards so will add the mods when they are working  :)
(https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xfa1/v/t1.0-9/10458162_881517768581159_7005823916476558172_n.jpg?oh=437498e355730b94e23a4832c416a942&oe=55F41C99)
Title: Re: CB55 Mods *Updated*
Post by: Leonard Charles on June 16, 2015, 10:26:07 AM
I had a go at dropping the kick down in pitch, I found replacing c10 with a higher value Cap made a good drop in pitch, more sub for your buck. I replaced the 68nf for a 100nf. 

I also added a switch and code (104) cap to C23 on the snare circuit. This means that when you flick the switch the snare note drops an octave(ish), sounds awesome. If you have done the other snare mods then they wont work on the lower octave but will still work on the higher octave.
Title: Re: CB55 Mods *Updated*
Post by: 01012k7 on June 17, 2015, 12:17:36 AM
I had a go at dropping the kick down in pitch, I found replacing c10 with a higher value Cap made a good drop in pitch, more sub for your buck. I replaced the 68nf for a 100nf. 

I also added a switch and code (104) cap to C23 on the snare circuit. This means that when you flick the switch the snare note drops an octave(ish), sounds awesome. If you have done the other snare mods then they wont work on the lower octave but will still work on the higher octave.
sounds cool
Title: Re: CB55 Mods *Updated*
Post by: grilojoe on August 05, 2015, 08:23:55 AM
if i want to use individual level control for each drum sound, would I still need the mix level? Seems like it'd be redundant, meaning I could jumper pads 2 & 3 where that pot goes.

Also, I thought I'd try using a dual gang pot for the snare and hats so noise that goes straight to the mix out for each would be controlled at the same time as the individual drum sounds.

Have I missed anything?
Title: Re: CB55 Mods *Updated*
Post by: Gunnar333 on July 14, 2016, 08:32:26 PM
if i want to use individual level control for each drum sound, would I still need the mix level? Seems like it'd be redundant, meaning I could jumper pads 2 & 3 where that pot goes.

Also, I thought I'd try using a dual gang pot for the snare and hats so noise that goes straight to the mix out for each would be controlled at the same time as the individual drum sounds.

Have I missed anything?

Did you tried it? Does it work as expected?
Title: Re: CB55 Mods *Updated*
Post by: cgodzillai on October 23, 2016, 03:26:37 PM
Hi,

i received this bord last year and never started it.
i want to go fo for the basic version with seperate outputs.
but of course the gert mod looks nice although my knowledge on electronic is so limited i'm afraid to read the drawings wrong and do something bad.

But let's be ambitious i have a question you guys might be able to answer.
i do soundtrack more then EDM. I love to use some small attack time on analog drums (!) it removes some punch and can transform the sound to something almost noisy. that is perfect for underscor pulsation rather than rythmic drums

is there any chance to mod something where we could get an attack time knob on the sounds ?(even a few milliseconds)
Title: Re: CB55 Mods *Updated*
Post by: timequake on February 05, 2018, 12:51:45 PM
After hearing the recording at Soundcloud... Does BD Resonance from Gert's mods act as BD Decay?

I just got the PCB and I am trying to organize different mods I see in this thread? Has anyone tried the mods Barcode posted?
Title: Re: CB55 Mods *Updated*
Post by: tigerstyleee on August 18, 2018, 06:57:37 PM
Anyone willing to sell their build or to make a new one for money? Thanks!
Title: Re: CB55 Mods *Updated*
Post by: kragg on February 21, 2019, 02:15:03 PM
Hello
I am new here, and just bought a CB55 pcb.
I would like to add a couple parameters to tweak for each drum sound, and i am wondering if there are any mods for the hihats ?
Is there any way to change the decay and the tuning of the hihats (or any other parameter) as easily as for the other drumsounds ?
Thank you
Title: Re: CB55 Mods *Updated*
Post by: kragg on February 22, 2019, 02:24:34 PM
Hello,

- About the BASS DECAY mod (replaceing R33 -820R- by a 1K pot+ trimmer) : will increasing the resistance increase the decay, or actually reduce the decay ? I am wondering this, because the suggested mod value is « only » twice the original resistance value, and the standard bassdrum of the DR55 doesn’t feature a very long decay. So, will increasing the R33 resistance to a 1K pot+500R trimmer will only allow for twice longer bass drums, or should i try with a 2,5K pot if i am aiming for very long bassdrum sounds ?


- About the RIMSHOT tune, I have found two suggested ways to make the modification, and i would like to have a confirmation that i didn’t make any mistake and/or that the modification is verified :  On the circuitbenders forum, i read that in order to allow for changing the rimshot tune, i have to replace R43 (2,2M) with a 1M pot + 2M trimmer.
But on « bestsoldering » website (which also make a PCB), they suggest to change R44 from the original schematic (which is a 22K resistor) with a 50K pot.
Could anyone confirm that changing CB55’s R43 (2,2M) with a 1M pot + 2M trimmer is the right way to do (or, at least, verified) ?

- I didn’t see any mods related to the HI-HATS on the  circuitbenders forum. But, on some websites, i have read that some mods could be done for the hihat decay and hihat tune :
1- putting several capacitors on a switch instead of CB55’s C35 (6,8nF) might change the hihat tune : could you confirm that ?
2- And it seems that the hihat decay could be set by replacing R55 (1M) from the original schematic with a 2M pot. On the  circuitbenders CB55, is « R55 » replaced by « R66 » or « R70 » (both are 1M) ? So which one is the one to change ? And do you know if the mod would work ?

- At last, I am willing to make one or two mods to the snare drum, but i don’t want to mess the nice sonic balance of the original sound and lose its overall character. Do you have any advice ? Which mod(s) would be the best for you ? Decay noise (R58 replaced by a 1M pot)?Pitch Element decay (R52 replaced by a pot) ? Pitch Element tune (R50 replaced by a pot) ? Or any other mod ?

Thank you in advance !
 ;)
Title: Re: CB55 Mods *Updated*
Post by: zorius on February 26, 2019, 07:45:48 AM
I have a working build, although a bit noisy. And with the tone/volume section there is even hum. So I cannot use that part. But it's not a problem, because I realized, that I would like to finish it with individual outs wired into a small 4 channel mixer board, and put it also in the box with 4 vol pots.
And I will use another own designed layout, based on the EHX LPB1 booster and the 2 band James Tone Stack. It also will go into the enclosure.
The midi is working too, as I mentioned in the other topic.
But with the mods, I was not lucky. The only usable ones are: bass decay, bass pitch and noise amount.
I do not want to box it, until the mods are not cleared. It would be very great, for once and for all to have the working mods listed, maybe with sound demos. Anyone? It would be great to clarify it already! Please, thanks!
Title: Re: CB55 Mods *Updated*
Post by: kragg on February 26, 2019, 01:09:31 PM
Thank you for your feedback.

Quote
The only usable ones are: bass decay, bass pitch
Do you think that with the suggested values (1Kpot+500r trimmer), the bass decay range is good ?

Which mods did you try and ended up finding not usable ?
Did you try the suggested mods for the rimshot (tune and decay) ? Didn't you like it ?
Did you try some mods for the snare and the hihats ?
Title: Re: CB55 Mods *Updated*
Post by: kragg on March 02, 2019, 01:38:56 PM
Hi,
How hard (easy?) would it be to add leds when each voices are triggered ?
Title: CB55 mods
Post by: bodster on April 16, 2019, 06:20:31 PM
Hi people,

First post on here, so apologies in advance for any duplication or repetition on my part.

Has anyone got a definitive list of all the mods for this groovy little machine? I've built a really nice fully-working model, with switched separate outputs and no hum or crackle or anything like that. I also now have a rather smart looking Eurorack front panel for it when finished. I'm currently controlling it very nicely from my Beatstep Pro.

I'm sure I wouldn't be the only person who would really benefit from a good, solid list of mods. If I can get them all to work I might even produce a basic updated version of the 'build manual' schematic for them...

I also have a rather shambolic list of possible mods for it, none of which I am 100% sure about yet... I am relatively new to DIY building so I still have some huge gaps in my basic knowledge, so what may seem simple to you guys might be completely new to me.

Here is the list I've compiled with my basic queries afterwards:

Bass drum decay:
Replace R33 with a 1kb pot and a 500R trimmer

Bass drum pitch:
Replace R31 with a 1mb pot and a 2m trimmer

Snare drum pitch:
Replace R50 with a 1mb pot and 2m trimmer

Rimshot pitch:
Replace R43 with a 1mb pot and 2m trimmer

To all of the above mods I have the same basic question - replace the resistors how? In what order/sequence? Using which pins to which ends of where the resistors where exactly?

I've also seen that some people have made mods for snare drum decay and colour, as well as the possibility of an 'open' hihat trigger...

Has anyone successfully performed these other mods?

Also, one final question. I have got separate outputs working fine, but I am such a newbie to this that I am not really sure even how to go about adding a level control for each sound. I understand that this must be by adding a pot for each sound, but what value should I use?

Sorry for all these questions and please feel free to tel me to f**k off, but the only way I know to learn is by asking others with more knowledge than me!


Cheers,


Bod








Title: Re: CB55 Mods *Updated*
Post by: kragg on April 16, 2019, 09:04:06 PM
Congratulations for your working build.
I built mine a couple weeks ago, and i'm still working on mods.
My advice would be to take time to tweak and experiment.
Bassdrum Decay is easy.
Rimshot mods are very interactive : changing one value can impact other rimshots mods, so again experiment (i ended up not keeping the decay mod, as along with tuning, it could go into self-oscillation too easily).
Snare decay is easy, too, and quite effective.
I also put several capacitors on a rotary switch, so i can have several hi-hat tune/filter setings, which i like.
I didn't manage to find a nice hi-hat decay mod.