electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time

poster

Please visit the chat
 Forum index » DIY Hardware and Software » The layout factory
808 Bass Drum Clone Eagle PCB & CNC Gcode
Post new topic   Reply to topic
Page 2 of 3 [55 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2, 3 Next
Author Message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Sun May 08, 2016 1:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

That sounds good for accents. What about triggers? Also, do you have any experience with multi-channel sample & hold ICs? eg. SMP08FPZ
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 2100
Location: Chicago
Audio files: 16

PostPosted: Sun May 08, 2016 6:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

I apologize, I suck at keeping context on threads that spread out over time.

Hm.....

The real 808 has a master clock that actually has the variable high trigger signal combined with it. Any given voice is enabled by its individual gate, but the trigger (going into the "Accent" part of the circuit as they are often labelled when made separate) is what made it actually sound. The microprocessor on the 808 runs on 5V, so that gate has to be a 5V gate, and could be driven directly by whatever MCU you plan to use.

This doesn't let you have separate accent per voice, but I'm sure part of why they did it this way is related to the same problem you're running up against.

May not help with your MIDI part of the project, but just some thoughts....
Back to top
View user's profile Send private message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Sun May 08, 2016 6:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

I think you are saying that the signal through 22K to the first NPN's base on each voice is a 5V gate. In that case, I just keep that line at 5V and operate the voice with the "accent" 4-14V pulse, correct?
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 2100
Location: Chicago
Audio files: 16

PostPosted: Sun May 08, 2016 7:39 pm    Post subject: Reply with quote  Mark this post and the followings unread

If you leave it always on, then you're still going to have to solve the problem of triggering voices individually. Whereas if you do like the original does, and only gate the voices you want to sound on a given step, that can be handled by the MCU directly or with minimal buffering, and leave you to only need one set of circuitry to generate the 4 - 14V pulse.

If I'm not making any sense, I would recommend reading through the 808 service manual, it's actually pretty well described there.
Back to top
View user's profile Send private message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Sun May 08, 2016 8:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

In this MIDI version, there is no concept of steps and I am always triggering voices individually. Our 12 channel DAC or set of sample and hold circuits solve the problem of individual triggers, correct? So I could keep all gates at 5V and just send 12 separate scaled pulses for the instruments that should play.
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 2100
Location: Chicago
Audio files: 16

PostPosted: Sun May 08, 2016 10:06 pm    Post subject: Reply with quote  Mark this post and the followings unread

It's worth trying Smile
Back to top
View user's profile Send private message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Mon May 09, 2016 7:37 am    Post subject: Reply with quote  Mark this post and the followings unread

I guess the only signal that matters for separated voices is what happens at the collector of the PNP. I wish I thought of that before I built every single voice board with the gate circuit. Oh well head banging monitor
Back to top
View user's profile Send private message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Tue May 10, 2016 11:27 am    Post subject: Reply with quote  Mark this post and the followings unread

It does seem that keeping the gate at 5V allows the instruments to be triggered with a single scaled accent pulse. I want to make sure the always-open gate is not allowing signal bleed, but I'm probably going this way for the 12ch interface... separate power+trigger distribution board that sends these accent pulses via 12 euro-power connectors.

UPDATE: Layout and DAC code verified. I still need to build the power distro boards.


midi_to_cv.png
 Description:
 Filesize:  39.78 KB
 Viewed:  208 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

midi_to_cv.png


Back to top
View user's profile Send private message
jbeuckm



Joined: Nov 30, 2008
Posts: 165
Location: Stockholm
Audio files: 9

PostPosted: Tue May 24, 2016 6:35 am    Post subject: Reply with quote  Mark this post and the followings unread




image.jpeg
 Description:
 Filesize:  1.46 MB
 Viewed:  233 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

image.jpeg


Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Thu Jan 10, 2019 5:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi, this is an amazing project, and the fact that you have made your hard work available to the public is just pure class!
I’m new to all of the synth building but I do love it and I’m learning every day.
Can I just ask a simple question? So the 6 pads x 2 that are on the midi - cv board, do they connect to the power distribution board to supply each module with cv and gate?
Sorry but I need to ask the silly questions to move forward 😊 many thanks Ryan
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Mon Mar 11, 2019 11:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi

Wow this is nice looking project! Downloaded your all 808 files and midi cv drums, does this need something else to be build?

Regards

Jake
Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Tue Mar 12, 2019 12:04 am    Post subject: Reply with quote  Mark this post and the followings unread

You will need a +/15v power supply. And a computer with midi
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Tue Mar 12, 2019 2:42 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

Could be done only with 808 modules without midimodule if add 3.5mm connector to trigger and add potentiometer to acc? So that I could trigger these from sequencer without midi.


Regards

Jake

Last edited by kropo on Wed Mar 13, 2019 6:01 am; edited 1 time in total
Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Tue Mar 12, 2019 3:25 am    Post subject: Reply with quote  Mark this post and the followings unread

Definitely, probably just a quick modification in eagle
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Wed Mar 13, 2019 12:31 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

On a series of stupid questions, but what are these U$1,U$2, U$3 etc?

On BD U$2 is power connector, U$1 seems to be between +12V rail and U$3 between -12V rail, so are these output pins to somewhere or jumperwires?


Regards

Jake

Last edited by kropo on Wed Mar 13, 2019 6:01 am; edited 1 time in total
Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Wed Mar 13, 2019 5:28 am    Post subject: Reply with quote  Mark this post and the followings unread

I don’t have the layout infront of me but at a guess I would say they are the trigger and accent outs, I will take a look when I’m home
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Wed Mar 13, 2019 6:01 am    Post subject: Reply with quote  Mark this post and the followings unread

RyBowk wrote:
I don’t have the layout infront of me but at a guess I would say they are the trigger and accent outs, I will take a look when I’m home


Hi

Thanks for helping.

I think trigger and accent are their own since these are straight "cuts" from power connectors -12v and 12v. So something must be there so that the rest of the board get power..

Edit, added screenshot

Regards

Jake


Screenshot 2019-03-13 at 15.05.01.png
 Description:
 Filesize:  48.31 KB
 Viewed:  23 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Screenshot 2019-03-13 at 15.05.01.png


Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Wed Mar 13, 2019 8:23 am    Post subject: Reply with quote  Mark this post and the followings unread

I’m pretty sure us2 is a generic name for the power connector
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Wed Mar 13, 2019 9:41 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

Could be, but yet I don’t seem to understand where or what should be connected there. Power connector is giving -12v and 12v and after that these will break the connection.

Regards

Jake
Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Wed Mar 13, 2019 10:34 am    Post subject: Reply with quote  Mark this post and the followings unread

Directly from +/-12v goes into a 100nanofarad capacitor that has a red line around it. Is that what you are referring to?
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Wed Mar 13, 2019 11:20 am    Post subject: Reply with quote  Mark this post and the followings unread

RyBowk wrote:
Directly from +/-12v goes into a 100nanofarad capacitor that has a red line around it. Is that what you are referring to?


Hi

No, that’s C4 atleast in +12v side and its from ground.

Regards

Jake

Edit. Picrure added. in the picture C4 is removed so it's much clearer image. So the U$1 here, I don't get it or what it should be.

Name: U$1
FootPrint: PB
Value: FB


Edit2, added picture from schematics.


Screenshot 2019-03-13 at 20.30.34.png
 Description:
 Filesize:  175.6 KB
 Viewed:  22 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Screenshot 2019-03-13 at 20.30.34.png



Screenshot 2019-03-13 at 20.37.57.png
 Description:
 Filesize:  183.9 KB
 Viewed:  21 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Screenshot 2019-03-13 at 20.37.57.png


Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Wed Mar 13, 2019 11:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

Ahh I see what you mean, those are ferrite beads
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Thu Mar 14, 2019 12:03 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

Thanks. Any idea what value or anything since the FB is not saying anything to me..


Regards

Jake
Back to top
View user's profile Send private message
RyBowk



Joined: Nov 25, 2018
Posts: 17
Location: England

PostPosted: Thu Mar 14, 2019 12:18 am    Post subject: Reply with quote  Mark this post and the followings unread

I’m at work at the moment but I’ll let you know what I used when I’m home
Back to top
View user's profile Send private message
kropo



Joined: Jan 29, 2019
Posts: 15
Location: Finland

PostPosted: Thu Mar 14, 2019 12:28 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

Thanks so much!

Regards

Jake
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic
Page 2 of 3 [55 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3 Next
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » The layout factory
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use