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Problem with pots for DR-110 mod
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neandrewthal



Joined: May 11, 2007
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PostPosted: Fri Jul 13, 2007 11:41 pm    Post subject: Problem with pots for DR-110 mod
Subject description: warning: may contain newbie questions
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Hi guys, I mostly lurk here as I'm a newb so I don't have much to add but I could use some help on this one.

I am currently trying these mods on my Boss Dr Rhythm 110:

http://www.theninhotline.net/dr110/110mods.html

They involve bridging certain resistors with 50k pots for control over the drums sounds. I had a 500k pot lying around and made some probes out of alligator clips and tried out those mods and even found some neat ones that aren't listed. With the 500k pot the factory drum sounds would not be changed for the first 90% or so of the turn of the pot, and during the last 10% of a turn the sounds would change drastically. Pleased with the results I bought a crap-load of 50k to try this out properly. Much to my dismay, as soon as I connect a 50k pot the sound is changed(ie. higher pitch or quicker decay) even when the pot is fully closed. These sounds are too high pitched and snappy to be usable as the basic settings so I wish I could still have to stock sounds when I want them, so now here come my questions:

Are pots supposed to act this way? Having a certain amount of resistance even when they are set to the 0 position? Any reason why a 500k pot has no noticable resistance in the 0 position while a 50k does? Could choosing a different value of pot solve this problem? I don't mind if there is a bit of a dead section for part of the turn, as long as it is not as bad as the 500k pot.

Thanks for reading. I appreciate any help I can get.

P.S. Does anyone know where to get a 26 pin, 3 row high density D-connector with solder cups besides mouser, jameco, digikey and FRYS? My problem with these is that they either aren't currently in stock or they charge 15-20$ to ship the little thing that weighs a couple ounces at most.

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Sebo



Joined: Apr 27, 2007
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PostPosted: Sat Jul 14, 2007 9:18 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi:
I own a DR-110, and I'm planing to do some mods too. But I think I will
take the PCB away and put it in a rack case.
I'm not shure if I understand exactly what you did, but I think you connected
the pot in parallel with the original resistor, and the mod implies replacing
the resistor with the pot. So you have to unsolder the resistor (or at least
one leg), and then solder wires to the pot.

Sebo

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ickystay



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PostPosted: Sat Jul 14, 2007 5:09 pm    Post subject: Re: Problem with pots for DR-110 mod
Subject description: warning: may contain newbie questions
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neandrewthal wrote:


P.S. Does anyone know where to get a 26 pin, 3 row high density D-connector with solder cups besides mouser, jameco, digikey and FRYS? My problem with these is that they either aren't currently in stock or they charge 15-20$ to ship the little thing that weighs a couple ounces at most.


If you don't mind used, look in the computer junk aisle of a thrift store. Those little switch boxes usually have a few chassis mounted to the back. Plus, you never know when a 25 pole 2, 3, or 4 throw rotary switch may come in handy.
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neandrewthal



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PostPosted: Sun Jul 15, 2007 9:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks guys I will have to try those and Sebo, I was sure that when it said "any resistance can be crossed" it meant to add the pot on top of the original resistor. Anyway, I will try removing a resistor and see what happens.
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goodrevdoc



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PostPosted: Sun Jul 15, 2007 11:13 pm    Post subject: Re: Problem with pots for DR-110 mod
Subject description: warning: may contain newbie questions
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neandrewthal wrote:
P.S. Does anyone know where to get a 26 pin, 3 row high density D-connector with solder cups besides mouser, jameco, digikey and FRYS? My problem with these is that they either aren't currently in stock or they charge 15-20$ to ship the little thing that weighs a couple ounces at most.


www.digikey.ca
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andrewF



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PostPosted: Tue Jul 17, 2007 3:10 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi
i did my dr110 early this year.
Most mods work fine but i regret not fitting volume pots for each sound or individual outs, would be worth investigating

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neandrewthal



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PostPosted: Tue Jul 17, 2007 7:47 am    Post subject: Reply with quote  Mark this post and the followings unread

Wow! That looks awesome. Did you remove all the original resistors? Also, what do all those jacks do?
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andrewF



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PostPosted: Tue Jul 17, 2007 8:31 am    Post subject: Reply with quote  Mark this post and the followings unread

If you haven't seen it this page has detailed instructions -
http://www.hoohahrecords.com/resfreq/mods/dr110/index.html

most of my mods are from here
the jacks are
clock in
CV inputs as per Res freq page
accent out
audio out (but I point out again try and work out volume pots for each sound or individual outs)
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neandrewthal



Joined: May 11, 2007
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PostPosted: Tue Jul 17, 2007 9:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Doh, I wish I had seen that sooner. It makes the mods I was trying to do look like amateur stuff. For the circuits like this:
http://www.hoohahrecords.com/resfreq/mods/dr110/snare.html
If I opted not to add a CV in would I still need the transitor, or do I just leave the pin that goes to the CV control pot disconnected?
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Sebo



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PostPosted: Tue Jul 17, 2007 9:27 am    Post subject: Reply with quote  Mark this post and the followings unread

If you don't need the CV in, you just have to replace the resistor by a pot.
Example: For the snappy level replace R81 for a 50K lin pot.

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bassmosphere



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PostPosted: Sat Oct 11, 2008 7:37 am    Post subject: Hoo Ha Records Site
Subject description: Anyone have a backup?
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This site is referenced a bunch of times and I'd like to check out the information, but it's long gone by now.

Anyone have this info kicking around?
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Sebo



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PostPosted: Sat Oct 11, 2008 8:38 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi:
Here is a zip with the Resonant Frequency mods, plus some mods from
another site.


Boss DR-110 Mods.zip
 Description:
DR-110 mods

Download
 Filename:  Boss DR-110 Mods.zip
 Filesize:  821.45 KB
 Downloaded:  1092 Time(s)


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bassmosphere



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PostPosted: Sat Oct 11, 2008 2:47 pm    Post subject:  Thanks Sebo Reply with quote  Mark this post and the followings unread

Thanks for this. The stuff from the Resonant Frequency is very well documented. I've already done the added "thump" mod of placing a cap onto R70 and I get some nice bottom now.

Would there be any way to blend in the effect of the cap by using a pot?
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Uncle Krunkus
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PostPosted: Sat Oct 11, 2008 5:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

neandrewthal wrote:
Thanks guys I will have to try those and Sebo, I was sure that when it said "any resistance can be crossed" it meant to add the pot on top of the original resistor. Anyway, I will try removing a resistor and see what happens.


By putting a pot across a resistor (in parallel) you will always be decreasing the value of the resistor, and therefore raising the pitch or shortening the decay. This will seem negligible at the far end of a pot which is alot bigger than the fixed resistor, because of the way parallel resistors are calculated.

Rt = 1/(1/R1 + 1/R2)

Say the fixed one was 2K and the pot was 200K. Then, with the pot all across the 2K you get

Rt = 1/(1/2 + 1/200)K
= 1.98K and you wouldn't hear the difference. But at the other end, (where the pot is only, say, 5K) you get

Rt = 1/(1/2 + 1/5)K
= 1.42K and this starts to change the overall value significantly

Note how small 5K is compared to the full travel of the pot?
Note also that you can't actually dial in the exact original value if the pot is in parallel, AND you can potentially dial in 0 ohms of resistance. This shouldn't cause problems in most circuits, but it could burn something out in others, and for that reason is not the way to do it.

The best way is to replace the original resistor with a fixed resistor of about half of it's value, in series with a linear pot of the original value. This way, you can't dial in 0 ohms, but you can go above and below the original, whose value can still be found roughly in the middle of the pot.

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Uncle Krunkus
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PostPosted: Sat Oct 11, 2008 5:12 pm    Post subject: Re: Thanks Sebo Reply with quote  Mark this post and the followings unread

bassmosphere wrote:
Thanks for this. The stuff from the Resonant Frequency is very well documented. I've already done the added "thump" mod of placing a cap onto R70 and I get some nice bottom now.

Would there be any way to blend in the effect of the cap by using a pot?


Replace the cap (across the original resistor) with the same cap plus a linear pot in series. You'll have to experiment with the value of the pot, but when the pot is 0R you'll get the full effect of the cap, and when the pot is a number of times the size of the original resistor, the effect of the cap will be muted.

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bassmosphere



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PostPosted: Sat Oct 11, 2008 6:06 pm    Post subject:   Reply with quote  Mark this post and the followings unread

Thanks for your reply. The stuff about the resistor values makes complete sense. What you said about the resistor values makes sense. Here is an example of the only two ways I can think to lay out the circuit. Is the second way what you mean by in series?

Also, the mod calls for the use of an electrolytic cap which I don't understand. Why not a ceramic?


DR-110 BD Circuit1.JPG
 Description:
Two ways, series and parallel I am assuming.
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DR-110 BD Circuit1.JPG


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neandrewthal



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PostPosted: Sat Oct 11, 2008 7:19 pm    Post subject: Reply with quote  Mark this post and the followings unread

Wow, I forgot this old thread was here Laughing I did end up removing the resistors and replacing them with pots. I also found a way to "blend in" the thump by replacing a resistor with a pot as well, but I can't remember which one. I'll have to pop it open and take a peek. I'm 90% sure I didn't use a capacitor.


DR110.jpg
 Description:
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 Viewed:  374 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

DR110.jpg



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Uncle Krunkus
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PostPosted: Sun Oct 12, 2008 3:48 am    Post subject: Reply with quote  Mark this post and the followings unread

bassmosphere wrote:
Thanks for your reply. The stuff about the resistor values makes complete sense. What you said about the resistor values makes sense. Here is an example of the only two ways I can think to lay out the circuit. Is the second way what you mean by in series?

Also, the mod calls for the use of an electrolytic cap which I don't understand. Why not a ceramic?


Yes, the second way is right.
Ceramic caps don't go very high in value. Max of about 100nF. You probably need a value more around 1uF. Make sure you use an NP or BP cap (ie; non-polarised) unless you know which side of the circuit is more +ve.

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blue hell
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PostPosted: Sun Oct 12, 2008 4:48 am    Post subject: Reply with quote  Mark this post and the followings unread

Uncle Krunkus wrote:
Ceramic caps don't go very high in value. Max of about 100nF.


The world is changing, for instance see : http://www.novacap.com/product_page.php?pk=PR30

Quote:
High Capacitance Value MLC capacitors in values up 100 Microfarads.

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also .. could someone please turn down the thermostat a bit.
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Uncle Krunkus
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PostPosted: Sun Oct 12, 2008 5:06 am    Post subject: Reply with quote  Mark this post and the followings unread

Yeah, I know, but,.... in the real world,....
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blue hell
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PostPosted: Sun Oct 12, 2008 5:47 am    Post subject: Reply with quote  Mark this post and the followings unread

Uncle Krunkus wrote:
but,.... in the real world,....


We're using them Wink

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Jan
also .. could someone please turn down the thermostat a bit.
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bassmosphere



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PostPosted: Mon Oct 13, 2008 6:19 pm    Post subject: Sebo or anyone else Reply with quote  Mark this post and the followings unread

Sebo wrote:
Hi:
Here is a zip with the Resonant Frequency mods, plus some mods from
another site.


Thanks again for upload those files. There was some other information on that site:

110sync_components.pdf
110sync_cuts.pdf
110sync_overview.pdf
110sync_ribbon.pdf
110sync_schemo.pdf
110sync_solder.pdf

Sebo, or anyone else happen to have these online?
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Sebo



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PostPosted: Tue Oct 14, 2008 11:56 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi:
Here are those files, I didn't post them before becasu only shows how to
add sync to the DR-110, but a very basic 12 ppq input, that's not very
usefull. There are various more interesting sync mods over the net (24
ppq, or even MIDI sync).

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bassmosphere



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PostPosted: Thu Oct 30, 2008 4:49 am    Post subject:  Adding Drum Triggers
Subject description: There is information on adding triggers, but I just want to be sure it's done correctly.
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Thanks again Sebo! I was hoping that info explained something about building a trigger-in interface.

George Lazenbleep posted something on his blog on how to do this, and now I am at least heading in the right direction. What I want to do, ultimately is use the DR-110 as a drum module and just trigger the drums via MIDI. If I understand the instructions correctly, what I need to do is apply voltage to the correct part of the switch matrix. Here is what threw me through a loop though:

"There may be other permutations that cause the kick to sound but beware! D1B to D8B is the only connection that is isolated from the other buttons by the diodes."

Looking at the schematic, it makes sense but the the PCB confuses me. I am able to trigger all the sounds, but want to be sure I've done it correctly. Is there a way to check my work using a multimeter?

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machine.cuisine



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PostPosted: Thu Oct 30, 2008 3:07 pm    Post subject: Re: Adding Drum Triggers
Subject description: There is information on adding triggers, but I just want to be sure it's done correctly.
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bassmosphere wrote:
Thanks again Sebo! I was hoping that info explained something about building a trigger-in interface.


Looking at the schematic, it makes sense but the the PCB confuses me. I am able to trigger all the sounds, but want to be sure I've done it correctly. Is there a way to check my work using a multimeter?

[/img][/img]


Here is my (Magnuson helped me with this a few years ago) way to add trigger ins to dr-110:

Take the dr-110 lid off. Go to where the individual voice buttons (BD, SD, etc) touch the top of the top-pcb (the digital pcb, you'll see copper 'X's.)

Get a wire and short these connections (use common sense, here) where the button would normally short the connection (therefore firing the voice). You have tricked the dr-110 that you have pressed a button - but you've actually just replicated what the button does.

Note the 2 connections which will fire a certain voice and write them down. From what I remember, there are actually 2 common points and the rest are individualized by voice, but you can use a pair-per-voice if you like.

Now, there is a way to do this "shorting" electrically - via an external trigger.

The trigger must be conditioned so that it doesn't hurt anything inside the dr-110. So use a diode clamp (one diode to +5V and one to ground) which will conduct any voltages higher than +5V or lower than ground (+/- 0.7V).

This conditioned trigger can then be sent (maybe after a current-limiting resistor) to the base of a common NPN transistor. The collector and emitter of the NPN should be connecting across the "2 points" (which you found earlier) that fire a voice. Repeat for all the voices you want to trigger.
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