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 
 Forum index » DIY Hardware and Software
808 Kick Drum [PCB]
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 2 [26 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: 1, 2 Next
Author Message
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Wed Mar 07, 2012 3:24 pm    Post subject: 808 Kick Drum [PCB] Reply with quote  Mark this post and the followings unread

I posted this on Muff as well - so apologies for any cross forum redundancies, but..

I have a bunch of PCBs of final rev of my 808 kickdrum layout. It's basically the Roland circuit, with some minor changes to the trigger input (based on Eric Archer's website), and with the common mods incorporated. (A frequency pot, and the optional decay mod via a resistor value change)

I don't have the BOM online yet - but I'll throw it on my website soon. It's an easy/quick build, nice small pcb.

This is the first PCB I've offered, but it's been tested by a bunch of folks with lots of happy kickin finished projects out there. It's a double sided, very high quality lead-free board - fabbed in the US.

I'm selling them for $25USD - free standard international shipping. (I'll ship a replacement if something is lost or damaged)

You can see from my pics that I have a solid test bed for comparisons. It sounds legit and awesome.

PICS and redundant info: http://www.anestheticaudio.com/?page_id=153

Bipolar power - works great with 2 9volt batteries, or a +/-12 or 15 supply.
I have a Mouser Project/BOM I can share if anyone wants it. (The parts I buy for it come to around $15USD.

PM me if you're interested! (Also more drum modules to come - either the 909BD, or the Simmons SDS3 will be next - both are in some sort of middling stage of development.)
Back to top
View user's profile Send private message
Dougster



Joined: Sep 20, 2005
Posts: 272
Location: Tucson, AZ, USA

PostPosted: Wed Mar 07, 2012 4:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hope you don't mind me asking a few questions... Wink

What is the format of your board? (In other words, what is overall size and the mounting hole geometry?) Have you been able to compare the sound of the BC transistors with the original 2SC versions? And what is the 1n914 for? I'm not familiar with that one...

FWIW, my vote for the next pcb would be the SDS3...

Regards,
Doug

_________________
Once you start down the modular path, forever will it dominate your destiny!

Every DIY person should own a copy of Electronotes: http://electronotes.netfirms.com

Blue LEDs are evil.
Back to top
View user's profile Send private message
jumunius



Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13

PostPosted: Wed Mar 07, 2012 5:21 pm    Post subject: Reply with quote  Mark this post and the followings unread

Dougster wrote:
Have you been able to compare the sound of the BC transistors with the original 2SC versions?


Oooh I'm curious about that too. They have NOS ones cheap at Vintage Planet and as I recently ordered some old Roland transistors there, I'm kicking myself for leaving these off my order. I have already ordered one of Jesse's boards after all.

Quote:
And what is the 1n914 for? I'm not familiar with that one...


4148 type diode I believe.

_________________
-Jim
Back to top
View user's profile Send private message
Dougster



Joined: Sep 20, 2005
Posts: 272
Location: Tucson, AZ, USA

PostPosted: Wed Mar 07, 2012 6:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

jumunius wrote:
Quote:
And what is the 1n914 for? I'm not familiar with that one...

4148 type diode I believe.

There are normally two 1n4148 diodes in the 808 kick. I'm curious about the third diode that he has included...

Regards,
Doug

_________________
Once you start down the modular path, forever will it dominate your destiny!

Every DIY person should own a copy of Electronotes: http://electronotes.netfirms.com

Blue LEDs are evil.
Back to top
View user's profile Send private message
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Wed Mar 07, 2012 6:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

Dougster wrote:
Hope you don't mind me asking a few questions... Wink


I don't mind at all!

Dougster wrote:
What is the format of your board? (In other words, what is overall size and the mounting hole geometry?)


I don't eagle in front of me - so I'll need to get back to you on the size and geometry - but it's no specific format. I just made the board as compact as reasonably possible, and put holes in the corners for mounting to... something.

Dougster wrote:
Have you been able to compare the sound of the BC transistors with the original 2SC versions?


I haven't built one up with original transistors- I'm very curious about that myself. My version with BC transistors sounds very close to my real TR-808 - but I haven't done a careful A/B at all.

Another forum member on Muff is planning on building a version with original and one with subbed transistors - I look forward to hearing the results.

Dougster wrote:
And what is the 1n914 for? I'm not familiar with that one...


From memory I believe the 1n914 is to make the trigger a little more compatible with a wider range of inputs. A mod I picked up from Eric Archer's website..

Dougster wrote:
FWIW, my vote for the next pcb would be the SDS3...


Yeah - that's what I'm most excited about too! I'm trying to revive the docs from the project in the (likely dead) threads on this forum. I'll keep you posted!
Back to top
View user's profile Send private message
Dougster



Joined: Sep 20, 2005
Posts: 272
Location: Tucson, AZ, USA

PostPosted: Wed Mar 07, 2012 7:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

jmejia wrote:
I haven't built one up with original transistors- I'm very curious about that myself. My version with BC transistors sounds very close to my real TR-808 - but I haven't done a careful A/B at all.

OK, cool. I still have an extra MB-808 prototype PCB, so I'll order some of those newer parts and build it to see how it compares...

Quote:
From memory I believe the 1n914 is to make the trigger a little more compatible with a wider range of inputs. A mod I picked up from Eric Archer's website..

Ah, I found that on Eric's site, thanks!

Regards,
Doug

_________________
Once you start down the modular path, forever will it dominate your destiny!

Every DIY person should own a copy of Electronotes: http://electronotes.netfirms.com

Blue LEDs are evil.
Back to top
View user's profile Send private message
LektroiD



Joined: Aug 23, 2008
Posts: 1005
Location: Scottish Borders
Audio files: 2
G2 patch files: 2

PostPosted: Thu Mar 08, 2012 4:25 am    Post subject: Reply with quote  Mark this post and the followings unread

One question, does it have a scalable pitch CV input?
Back to top
View user's profile Send private message Visit poster's website
sneakthief



Joined: Jul 24, 2006
Posts: 569
Location: Berlin

PostPosted: Thu Mar 08, 2012 4:27 am    Post subject: Reply with quote  Mark this post and the followings unread

When I was building my MB-808, I had a little "accident" and broke my maracas, claves & rimshot.

While troubleshooting, I tried swapping the transistors with BC's. As far as I could tell, there wasn't much sonic difference - and certainly not the difference that you find between real TR-808's.

However, I did notice that when placed in the trigger circuit, the BC's are slightly quieter.

I'm really lucky because the local electronic store, segor.de has a whole bunch of Japanese 2SC's and 2SA's. I'm not sure if Segor ships internationally though.

_________________
Sneak-Thief - raw electrofunk
Back to top
View user's profile Send private message Visit poster's website
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Thu Mar 08, 2012 11:26 am    Post subject: Reply with quote  Mark this post and the followings unread

LektroiD wrote:
One question, does it have a scalable pitch CV input?


It doesn't have a CV input for pitch - the only CV in is accent - it'd be easy to hack in a vactrol if you like, though making it scalable is gonna take a little more work I imagine. Smile
Back to top
View user's profile Send private message
xpmtl



Joined: Aug 10, 2007
Posts: 162
Location: Brussels, Belgium

PostPosted: Fri Mar 09, 2012 1:23 am    Post subject: Reply with quote  Mark this post and the followings unread

sneakthief wrote:
I'm not sure if Segor ships internationally though.


Apparently they do. 10€ to EU and you got to request a quote for shipment outside EU.

I'll order some of these Japanese trannies as they are hard to get usually.

Thanks for the tip.

Edit : That's if I find them on their site, their search engine doesn't work and german is like chinese to me Smile

_________________
http://sdiy.xpmtl.net
Back to top
View user's profile Send private message
richardc64



Joined: Jun 01, 2006
Posts: 665
Location: NYC
Audio files: 26

PostPosted: Fri Mar 09, 2012 5:18 am    Post subject: Reply with quote  Mark this post and the followings unread

This is silly.

Why is there so much concern over transistors that aren't doing anything special? Most are simple inverters. One is a voltage-variable resistance. The only one that might be critical -- if you're some sort of audio snob -- is the output xistor, Q44.

Get a grip.

_________________
"I am endeavoring, ma'am, to create a mnemonic memory circuit... using stone
knives and bearskins." -- Spock to Edith Keeler
Back to top
View user's profile Send private message Visit poster's website
sneakthief



Joined: Jul 24, 2006
Posts: 569
Location: Berlin

PostPosted: Fri Mar 09, 2012 5:24 am    Post subject: Reply with quote  Mark this post and the followings unread

richardc64 - as I said, everything sounded pretty similar but BC substitutes created a lower trigger (and also accent) signal. That's pretty significant in my books.

If you're pinging a Bridged T-network with a trigger and the ping level is lower, then the tonality of the kick will certainly be affected. This isn't simply a matter of volume: http://www.soundonsound.com/sos/Feb02/articles/synthsecrets0202.asp

In any case, this was my experience and the results may vary depending on the rest of the components and their respective tolerances.

_________________
Sneak-Thief - raw electrofunk
Back to top
View user's profile Send private message Visit poster's website
jumunius



Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13

PostPosted: Fri Mar 09, 2012 12:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

xpmtl wrote:
10€ to EU and you got to request a quote for shipment outside EU.


Vintage Planet sells these for a dollar for a handful of each of these types. IIRC $15 minimum order gets you free shipping anywhere. It's really easy to find $15 of worthwhile electronics here, so if you're curious whether any of these transistors make a difference, you could decide for yourself for out for about $2.

_________________
-Jim
Back to top
View user's profile Send private message
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Fri Mar 09, 2012 3:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

Very nice looking board! Crayola should take note of this new phenomenon and bring out a "LAEN VIOLET" crayon.

I vote for SDS-3 next.

So ... I'll order up one of these boards from you, probably on Thursday (my payday). In the meantime I think you should consider posting your mouser BOM to this thread.
Back to top
View user's profile Send private message Visit poster's website
strategy



Joined: Jan 03, 2009
Posts: 85
Location: portland, oregon

PostPosted: Mon Mar 12, 2012 8:52 am    Post subject: Reply with quote  Mark this post and the followings unread

I just built jmejia's project, great fun and CHEAP way to an 808 kick drum! Just waiting for some of the enclosure elements so I can finish that part of it.

Strategy

infindebula wrote:
Very nice looking board! Crayola should take note of this new phenomenon and bring out a "LAEN VIOLET" crayon.

I vote for SDS-3 next.

So ... I'll order up one of these boards from you, probably on Thursday (my payday). In the meantime I think you should consider posting your mouser BOM to this thread.

_________________
--------
community-library.net/strategyhome.htm
Back to top
View user's profile Send private message Visit poster's website
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Tue Mar 13, 2012 12:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

infindebula wrote:
Very nice looking board! Crayola should take note of this new phenomenon and bring out a "LAEN VIOLET" crayon.


Awesome! sounds like you might be here in PDX? (time for me to pass this forum link on to Laen!)

Here is my mouser bom for those who want it:

http://www.mouser.com:80/ProjectManager/ProjectDetail.aspx?AccessID=95 0b04d9fc

And the original thread at muff if anyone cares to follow:
http://www.muffwiggler.com/forum/topic-54149-0.html&postdays=0&postorder=asc&highlight=
Back to top
View user's profile Send private message
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Fri Mar 16, 2012 4:28 pm    Post subject: Reply with quote  Mark this post and the followings unread

hehehe no... not a member of PDX, but I've had a few boards made by Laen. Such a nice and helpful guy who makes small runs of great quality boards for dirt cheap. They're turning up all over the synth DIY community.

I designed this oddball circular MIDIbox 808-based sequencer last year and had Laen make the boards. The firmware will send MIDI notes and/or analog triggers. All I need now are some cool analog drum voices!

http://www.youtube.com/watch?v=QHNgT8ISTMI

Anyway, yes, I'll take a board if you've still got 'em ... email to follow shortly.


>>EDIT: Thanks for the Mouser BOM, but the link doesn't work. For those who have trouble, here is the access ID:

950b04d9fc

Last edited by infindebula on Fri Mar 16, 2012 6:41 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
ian-s



Joined: Apr 01, 2004
Posts: 2647
Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 625

PostPosted: Fri Mar 16, 2012 4:36 pm    Post subject: Reply with quote  Mark this post and the followings unread

infindebula wrote:

I designed this oddball circular MIDIbox 808-based sequencer


That's real nice. Love the pattern rotate.
Back to top
View user's profile Send private message
LektroiD



Joined: Aug 23, 2008
Posts: 1005
Location: Scottish Borders
Audio files: 2
G2 patch files: 2

PostPosted: Fri Mar 16, 2012 6:42 pm    Post subject: Reply with quote  Mark this post and the followings unread

jmejia wrote:
Here is my mouser bom for those who want it:

http://www.mouser.com:80/ProjectManager/ProjectDetail.aspx?AccessID=95 0b04d9fc


dead link... well, not quite dead, takes me here:
http://uk.mouser.com/tools/Tools.aspx?Error=true

Any chance you could post the BOM directly into the forum, rather than linking a dead website. I don't even use Mouser in the UK, they are WAAAY to expensive with their shipping costs.
Back to top
View user's profile Send private message Visit poster's website
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Fri Mar 16, 2012 7:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

[quote="LektroiD"]
jmejia wrote:
dead link... well, not quite dead, takes me here:
http://uk.mouser.com/tools/Tools.aspx?Error=true


Scroll down the page, there's a field to enter the Access ID, paste in 950b04d9fc
Back to top
View user's profile Send private message Visit poster's website
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Fri Mar 16, 2012 11:19 pm    Post subject: Reply with quote  Mark this post and the followings unread

Woops sorry about the link typo guys. Somehow a space snuck in there! This should work for you:
http://www.mouser.com:80/ProjectManager/ProjectDetail.aspx?AccessID=950b04d9fc

And I can certainly post a more generic bom if you like.. though the mouser bom is maybe more useful since you can look up pin spacings, etc if you like!
Back to top
View user's profile Send private message
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Sat Mar 17, 2012 1:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

I decided to make an easily-readable BOM for my own reference, so I could quickly compare it to my own stock. I made a quick Macro to convert the Mouser table into a reasonably tidy spreadsheet. On the positive, I don't think I need to order anything!

I'm sharing it here for anyone who would like to look at it. Here it is as a CSV.

CSV can be imported into Excel / Google Docs / OpenOffice as a spreadsheet, or you can look at it as a text file. The prices are from the Mouser site in Canadian dollars. Note that one of the caps as specified is no longer available (marked "NLA") but is an easy sub (it's a 0.1 uF ceramic).


808bdbom.csv
 Description:

Download
 Filename:  808bdbom.csv
 Filesize:  3.74 KB
 Downloaded:  366 Time(s)

Back to top
View user's profile Send private message Visit poster's website
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Tue Apr 10, 2012 3:12 pm    Post subject: Reply with quote  Mark this post and the followings unread

Got my board! Good job, Mr. Mejia, this thing is smaller than the pictures would suggest.
Back to top
View user's profile Send private message Visit poster's website
infindebula



Joined: Sep 29, 2011
Posts: 28
Location: Canada

PostPosted: Sat May 05, 2012 7:06 am    Post subject: Reply with quote  Mark this post and the followings unread

OK, I've been populating this board as I find spare time. I decided (because of this thread) to use some 2SA733 and 2SC945 transistors instead of the BC transistors on the BOM.

(For those doing this, don't forget that the BC transistors are pinned C-B-E, while the Japanese 2SA/2SC transistors are E-C-B)

Now I'm just wondering:

The device calls for a pair of 5.9K resistors, which I don't have any of. No problem, I could get some - but I don't see 5.9K resistors on the original TR-808 bass drum schematic! Any explanation?

Also: Do I understand correctly that the only bass drum decay mod that's present here is the 42.2 K resistor? Is there anything else that is part of this circuit making up the decay mod? I was contemplating switching here between 42.2K and 47K (the original) - should I bother?

Thanks
Back to top
View user's profile Send private message Visit poster's website
jmejia



Joined: Mar 12, 2009
Posts: 114
Location: portland

PostPosted: Sun May 06, 2012 9:23 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for putting that spreadsheet together! I'll point others to it as needed!

a 47k resistor instead of 42.2k will give your circuit the factory decay. 42.2k extends the decay - to a point which should be more in line with the common decay mods that were/are done to a tr-808. I based this mod off of Robin Whittle's info here: http://machines.hyperreal.org/manufacturers/Roland/TR-808/mods/808.kick.decay.and.tuning.txt

Instead of putting a resistor in parallel I just change the value of the one.

I can't remember why I used a 5.9k resistor.. the original schematic calls for a 6.8k resistor in the same location. I imagine either would work fine... maybe any value in between? I don't know what the function of that resistor is.. it's R173 on the factory schematic.. maybe someone more knowledgeable can enlighten us?
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 2 [26 Posts]
View unread posts
View new posts in the last week
Goto page: 1, 2 Next
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software
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