Help with stripboard layout...

wizardsofzen · Joined: Jan 08, 2011 Posts: 14 Location: Zion

ah ha! there in lies the problem, i reside in the land of zen.

thanks for the new info, i've just wanted to board this for about 6 months now.

now i have an issue of where to find TL072P IC's or an equivalent replacement...

i do see some things that look close on mouser, but unsure, anyone have the culprit?

i do enjoy a good foray out of the land of zen once in a while, just not outside of eyesight of the doorway back in....

currently, this is my best guess - http://www.mouser.com/Search/ProductDetail.aspx?R=TL072ACPvirtualkey59500000virtualkey595-TL072ACP

Ben.H · Posted: Mon Jun 18, 2012 6:09 am Post subject:

Hi guys, I know this is an old thread but for future reference it should be noted I found the error that was causing the oscillator to not resonate correctly. The junction of R12, T2, R11 & C4 was being grounded, the track needs to be cut between C4 & R26 on the 13th line.

Hope this helps someone, took me freakin ages to find!
I've built the same circuit using the original eric archer layout and found they were sounding quite different previously
Stripboard is now working correctly!

-minus- · Joined: Oct 26, 2008 Posts: 718 Audio files: 13

Welcome and well done Ben.H! I'll have to look at this stripboard again. I managed to get reasonable sound out of it by triggering it from some other spot but it's still not quite right. I forget what I did... I probably posted about it Confused

.

I knew someone would solve this riddle before I died!

-minus- · Joined: Oct 26, 2008 Posts: 718 Audio files: 13

I'm making the other voices now on stripboard. Just linking...

http://electro-music.com/forum/post-368380.html#368380

gerbster · Posted: Tue Nov 13, 2012 10:34 am Post subject: A little help..

Hey All,

The last couple of weeks I've tried to get this strip board up and running but I'm afraid I'm stuck.. I was wondering if somebody who has finished this board successfully can give me some voltage values at some points on the board so I can track down the problem.

First, my setup:

- I've build a +/- 12V power supply and connected it to the stripboard with an extra +12V going into the accent
- the trigger is connected to a Highly Liquid MD24 board output (which gives +5V pulses, i've checked that)
- I've plugged in the output into my mixer

I've measured the voltages on the TL072, and they read + and -12 on pin 4 & 8, so that is getting power. However, I don't see anything coming out of T3. There is +12V on the collector but the base isn't getting anything from the trigger (I think.. Smile

)

Anyway, I was wondering, in this thread I've read something about supplying voltages to some points to manually trigger this circuit, but what points should that be?

Thanks in advance!

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RotomotioN · Joined: Mar 02, 2013 Posts: 9 Location: Netherlands

Hey Gerbster
You need a momentary switch between +V and the normal trigger input point

elmegil · Posted: Wed Mar 06, 2013 7:36 pm Post subject:

I don't know that I'd agree on a momentary...

There has to be positive voltage on both of the inputs for there to be a trigger. How much positive voltage can have a significant impact on how loud / hard a hit you get out of it.

Some people hook the accent (the "northern" input) to +V all the time. Others hook the two inputs together. In the original there wasn't any trigger conditioning (the diode and cap arrangement on the input) and you had the "common clock" (a combination of the clock and variable accent on steps when it was active, ranging from 4 to 14V) gated by the instrument step (5V).

I've found though, attempting to do it "the right way", something must be different about the modern components, because even with no instrument gate, I will get a trigger from a sufficiently high accent + clock. What I've done is tie those two together, and I'm generating the 1ms pulse from an Arduino so I don't have to worry about conditioning the input. If I were to make this a module, I'd use the conditioner though (I've got it on the stripboard, I just bypass it with the gate input).

elmegil · Posted: Wed Mar 06, 2013 7:39 pm Post subject:

BTW there's a lot more discussion of the 808 stripboard Bass Drum over on this thread, after the first page or two of talking about the high hats and cymbals.

http://electro-music.com/forum/topic-54826.html&postorder=asc

gerbster · Posted: Thu Mar 07, 2013 6:44 am Post subject: I'm an idiot

Well, it turned out i'm an idiot. After building a complete new 808 BD pcb from scratch that DID work i found that... I connected the output wire to the wrong pin of my output socket.

so now i have 2 fully working 808 BD's Wink

But thanks for your replies.