TR-808 Snare Stripboard

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

I have drawn up this stripboard diagram of the 808 snare. Unfortunately I have yet to build it and it is thus still 'unconfirmed' at time of posting. I have gone over this quite a lot and I'm pretty confident this will work. I am going away for a week or so, so wont have a chance to try it until I get back. Sad

I generally don't like postings of circuits which are unverified... but here I am doing it myself!! Laughing

If anyone is interested I shall be able to confirm this in about two weeks time, so check back then. In the meantime, if there is any brave soul willing to give this a punt, then great!! Also if someone with some spare time would like to go over the schematic and compare it to this stripboard layout, it would be much appreciated.... I may have missed something... you never know.

The schematic I worked off was the one Eric Archer did from the original Roland 808 one. You can find it here:

http://ericarcher.net/wp-content/uploads/2009/07/tr808_snare_diy_project.pdf

You'll notice the component labeling on my list follows Eric's. I did it this way to make this stripboard compatible with his schematic diagram. One other thing.... The 2N3704 transistor may not be easily obtainable these days. I believe the PN100 is the replacement for this.

I'll update these illustrations and keep them current if any corrections occur. Hope you like the retro 808 artwork! Laughing

EDIT: Updated component list 19 January 2011

TR808 SNARE.jpg

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TR808 SNARE bottom view.jpg

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TR808 SNARE components.jpg

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LektroiD · Posted: Wed Nov 17, 2010 9:04 pm Post subject: Re: TR-808 Snare Stripboard

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

sorry about that! Laughing

The images came up huge so I resized them.... they should be there now! Embarassed

Uncle Krunkus · Posted: Thu Nov 18, 2010 1:28 am Post subject:

That's a nice looking layout minus.
Well done.

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

Thanks Krunkus! Very Happy

This stripboard obsession is all your fault! Laughing

It all started with your WSG.... You know, stripboarders are a dying breed. Everyone seems to prefer perfboard (or should i say, perfer Laughing

). If this circuit tests ok, I might work my way through the rest of the voices.

v-un-v · Posted: Thu Nov 18, 2010 2:32 am Post subject:

Yes! Gorgeous artwork!! Cool

A mistake I often made in the past, coming largely from a graphic perspective, is that I got the artwork spot on, but my engineering skills left a lot to be desired (ie, they are shit!! Laughing

)

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

LektroiD · Posted: Thu Nov 18, 2010 11:11 am Post subject:

Looking forward to piecing this baby together. Love the artwork.

v-un-v · Posted: Thu Nov 18, 2010 12:48 pm Post subject:

I could put that component layout on a t-shirt it's that gorgeous!! Cool

v-un-v · Posted: Thu Nov 18, 2010 12:50 pm Post subject:

How did you do that artwork? Illustrator? Shocked

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

yep it's Illustrator.... on a mac I might add! Laughing

I love Illustrator! I use it for just about everything now... to the point where I am forgetting how to use photoshop. The gradient mesh tool is great too! The level of photorealism obtainable with that is amazing!!! Shocked

And it's vector too. I'm an old fart really when it come to computers. I was trained some time ago with technical pens, airbrushes and Letraset! Shocked

But I'm gradually learning the 'new way'! I'm glad you like it! Once the components are drawn its really just a copy and paste job.

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

I'm gathering components for this still. I thought originally that I'd find the capacitor values in MKT's, hence the diagram has been drawn with MKT's in mind. I am going to have to use some greencaps for some of them, but I imagine they should still fit the crowded layout. I'll have this built this weekend and will hopefully confirm this circuit then....

v-un-v · Posted: Mon Nov 29, 2010 3:40 am Post subject:

Looking forward to what you find & hear! Smile

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

I've just got home tonight, and it may be 3:30AM here but the board will be finished by sunrise... hopefully... Already I see a couple of things missing in the above diagrams. Embarassed

To the millions of solderers stuck and wondering what value R15 and R17 are Laughing

....

R15= 330R

R17= 15K

I seem to have missed these in the component list! I'll update the list shortly and label that page as being revised. I'm still hopeful that in the next few hours I'll be posting sound clips and a dodgy low res 2 mega pixel phone photo of the board... Well, that's the plan anyway! Laughing

EDIT: C5 = 6.8nF Embarassed

JRock · Posted: Thu Dec 02, 2010 8:17 pm Post subject:

That's nice! Looking forward to watching how this turns out Cool

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

OK! With a few minor hiccups, I have the snare functioning. I'm still having some triggering issues here though. I'm not able to trigger at the designated trigger point, but I seem to be able to trigger this from R14 (stripboard track 21) or R13 (stripboard track 19). Also I think I'll test and perhaps add Eric Archer's diode-cap-resistor network to make triggering independent of pulse width. This may mean an extra tiny board to the one I have but I'll post another top view diagram with this included soon.

Also... I'm notorious for getting pots wired the wrong way around! Laughing

I need to fix these up on the diagram... sorry about that. It's like the old adage of the toast always falling butter side down! I always get this wrong...

I'll do some quick recordings of it now.... I'll post again soon...

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

I still have to rewire these pots and fiddle with this trigger point, but here's a quick clip of what it sounds like. I'm triggering with a very simple 4017 based sequencer. First the snare on its own with some knob twiddling, then the snare and 808 kick clone found elsewhere in The Layout Factory:

808 Snare Test.mp3

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-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

Still trying to work out this triggering problem....

I thought I might have got the 556 transistor (T6) the wrong way around. As far as I can work out, this transistor has the same CBE pin layout as the 546. If this is the case, the diagram above has this orientated incorrectly. Embarassed

I have soldered a replacement the correct way around, but this has not solved the trigger issue. I'm still triggering from R14 (track 20 on the stripboard).

I have just looked at Eric Archers site and read this about his perf version:

If you are planning on triggering the circuit from a logic signal, the easiest way is to tie ACCENT to +12V (+15V), and connect the logic signal to TRIGGER.
You'll have to make the trigger pulse short (like 5ms) or you'llhear a double-trigger on the negative edge of the pulse.
Or you can add my diode-cap-resistor network (described elsewhere) that makes triggering independent of pulse width.

When I tie ACCENT to +9V I get a constant loud HISSSSSSS. I have also tried the Krunkus suggestion with the ACCENT pot from the 808 kick drum stripboard thread. It seems that this doesn't work either. So I'm a bit at a loss at the moment what to do. The problem is in this triggering section of the board. It triggers ok from the R14 point, with the ACCENT point untied to the +9V rail. I'd just like to get this working in the manner it should.

Any suggestions anyone? scratch

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

Now I'm thinking the T6 BC556 is actually the right way around. I'm looking at the stripboard version of the kick drum, and judging by that, I think the above diagram is correct...

As to why this isn't working as it should, I really can't fathom this out! scratch

I'll keep looking at this and hope something obvious jumps out at me.... but I can't see what.

RF · Posted: Tue Dec 07, 2010 1:46 pm Post subject:

Just a random thought w/out looking at it today - but have you tried a + and - 12 volt supply...or have you made allowance for using 9 volts with some component changes?

That may not be it - but it's a variable from the original, isn't it?

Good luck

bruce

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

No, I have not tried a +/- 12V supply. I guess I am going off the fact that the kick drum module runs of the two 9V batteries, so I assumed this would work in a similar manner. Thing is, I can get this to trigger elsewhere on the board... just not from the designated trigger point. It's kind of ok as it is, it's just bugging me that I cant figure out why this won't work as intended.

I've jumped onto some other soldering jobs in the meantime. I'll have to come back to this one. I'm sure there is a simple explanation somewhere.

Team Toothpaste · Joined: May 06, 2010 Posts: 25 Location: London

hi, minus. firstly, great work and thanks for this. i saw eric's clones a while ago and knew i'd have to make them at some point. i'm pretty new to this stuff and i'm definitely more comfortable with stripboard so thanks.

when you said

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

Yes they are different. The BC546 is a NPN transistor, and the BC 556 is a PNP transistor. They both have the same designators (is that the correct term?). What I mean is, if you hold the flat side facing you, the legs are from left to right: Collector, Base, Emitter. They are different though. You can't just use one or the other wherever you want. Laughing

I was just noting that the legs are the same... in the same order. Anyway, that 556 was correct in the diagram.

I pretty much went off the data Eric posted on his site. I followed his schematics and drew this off what he had, as well as checking the roland originals for this particular voice.

As to solving the riddle, I have yet to work this out. Embarassed

I will get back to this! I have been able to trigger from further along the line from the specified point, but not from the point it should work from. It's getting a bit late in the year to have this solved, but I will be coming back to it in January... I haven't given up on it yet!

Team Toothpaste · Joined: May 06, 2010 Posts: 25 Location: London

ah i see what you mean. good luck with this. looking forward to building this one now, but as you say it's getting a bit near to that hectic christmas/newyears/my birthday kinda time so i probably wont start on this until january. once i get started i'll post my progress on this thread if that's alright.

seasons greetings and all that

6079smith · Posted: Thu Jan 13, 2011 10:18 am Post subject:

If anyone's interested, I can confirm this works just fine... a couple of minor things on the layout and BOM (f. ex. the pinout of the 2n3704 isn't quite right) but aside from that it's fine. I'd recommend a Ken Stone gate to trigger converter in front of it (and every other percussion module) - it'll trigger from almost anything. Nice work!