Death by Audio - Apocalypse  [traced]

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Re: Death by Audio - Apocalypse

Postby Wiseblood » 15 Feb 2017, 00:50

It YATS
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Re: Death by Audio - Apocalypse  [traced]

Postby Cannibal » 16 Feb 2017, 15:17

My bad!!

There was a mistake and the pedal seemed to work properly due to the ultra-heavy amount of gain.
I corrected a couple issues and now it works. Treat the SCOOP transistor (NPN MPSA06) like a PNP - that means collector to GND.
Squarewave section TL072 has pin 3 and 5 connected to Vref.

Check the correct files below.

Also try different configurations on the pins of B100K (equalization) - depending on how you wire 1 and 3 it could act as a frequency cutter or the original EQ.
Maybe try A100K for a better control.
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Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

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Re: Death by Audio - Apocalypse

Postby johnk » 20 Feb 2017, 20:12

i drew up my own PCB layout for it using the posted schematic and built & tested it, but i think that it has some errors. the tone control doesn't work like the sample videos and two of the positions on the rotary have VERY LOW output so, IMO, this one isn't quite solved yet.
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Re: Death by Audio - Apocalypse

Postby johnk » 23 Feb 2017, 02:49

so no one has any corrections/suggestions?
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Re: Death by Audio - Apocalypse

Postby Cannibal » 24 Feb 2017, 10:35

Johnk, I didn't experience any of the low output issues.

Are you sure you did the very same of the schem? The only way you can have low output is by forgetting one of the input capacitors on the circuits (the 100 nf for example where the signal enters in the squarewave section of the circuitry) or on the same part of circuitry not connecting Vref to both pin 3 and 5 of the TL072. Don't look at the older post.
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Re: Death by Audio - Apocalypse

Postby johnk » 24 Feb 2017, 18:10

yes, i used the second schematic that you posted, but i used an MPSA05 for the PNP transistor (like the original). i did try an MPSA06 but got the same results (very low output)

by the way, your schematic and layout are different for the tone control. i tried it both ways and it still doesn't work like it does in the video demos.

the schematic is this:

eq cannibal schematic.jpg


and your layout is this:
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Re: Death by Audio - Apocalypse

Postby johnk » 25 Feb 2017, 23:43

BTW, the second schematic of the tone control (like your layout) works better.
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Re: Death by Audio - Apocalypse

Postby Cannibal » 26 Feb 2017, 16:08

Hey Johnk, thanks for your feedbacks!!

Mine has the tone control like made in the layout (the 2nd one you're referring about). As I told in a previous post, one can try different pin wirings on the tone control depending on what is needed. In the last layout acts mostly like it's supposed to do, but you can wire it the opposite way to make it working like a low/high-pass filter.

The original one I reversed has a MPSA06 so it's weird the thing about using another one. Also I don't have some 05 at hand to test how and if it works, maybe check its pinout.
But I don't think the low output is caused by this. Plus, I don't really have low output with my build, which is 100% like the last one you made reference to (the one with the better tone control and Vref on pins 3 and 5 of the TL072).
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Re: Death by Audio - Apocalypse

Postby johnk » 26 Feb 2017, 19:07

i'm running an MPSA06 now and the scooped setting still has VERY low output. i did solve the square wave setting's low output by changing a couple resistor values from what is shown in this layout. i put the xformer on a seperate daughter board so i could try both types and make for easier placement/fitment in the enclosure.
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Re: Death by Audio - Apocalypse

Postby johnk » 26 Feb 2017, 20:31

BTW, here's my PCB layout.

0001-Apocalypse cannibal Layout.png


and here's my main PCB's etch:

000001-Apocalypse PCB.jpg
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Re: Death by Audio - Apocalypse

Postby johnk » 02 Mar 2017, 06:12

well, i've checked everything and tried a zillion different transistors for the MPSA06 'scoop' circuit (i socketed that transistor) and it still has about a 10% or less of the volume than the other 4 settings. if i could just get it to be the same as the others, i'd probably be happy with it.
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Re: Death by Audio - Apocalypse

Postby Cannibal » 02 Mar 2017, 17:53

johnk wrote:well, i've checked everything and tried a zillion different transistors for the MPSA06 'scoop' circuit (i socketed that transistor) and it still has about a 10% or less of the volume than the other 4 settings. if i could just get it to be the same as the others, i'd probably be happy with it.


Weird :( wish I could mail or post a clip showing the volume I get, which is basically the same on every setting. Some extra punch on the Octave Clang section but it's ok.
Did you tried reversing the MPSA06 using the opposite pinout?
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Re: Death by Audio - Apocalypse

Postby Mich P » 03 Mar 2017, 08:34

Hi John K,
thanks for the circuit.
I have a question about the leading space of the diodes in your layout
that i notice it is 5 mm.
Is there a reason for that and why not using a bit more like 8mm
that way you could install the diodes horizontally.
Thanks,
Mich P.
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Re: Death by Audio - Apocalypse

Postby johnk » 05 Mar 2017, 21:04

Mich P wrote:Hi John K,
thanks for the circuit.
I have a question about the leading space of the diodes in your layout
that i notice it is 5 mm.
Is there a reason for that and why not using a bit more like 8mm
that way you could install the diodes horizontally.
Thanks,
Mich P.

Hi Mitch, they fit just fine at 5mm so i just did it that way. i do that with 1N4148's too.
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Re: Death by Audio - Apocalypse

Postby turdadactyl » 08 Mar 2017, 17:56

Maybe a dumb question, but why does this schematic use a 2x6 rotary and not a 2x5?
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Re: Death by Audio - Apocalypse

Postby Cannibal » 10 Mar 2017, 22:46

turdadactyl wrote:Maybe a dumb question, but why does this schematic use a 2x6 rotary and not a 2x5?

Hey there!
My supplier sells 2x6 only.
But on rotaries like these there is a metal ring with a tip. By adjusting the tip in the correct hole, you simply stops the rotations.
So the standard has 6 positions, but you can reduce them to 3, 4, 5 depending on where you place the metal ring.
Hope it's clear :) cheers!
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Re: Death by Audio - Apocalypse

Postby Lubdar » 12 Mar 2017, 00:32

The scoop stage will by default have lower volume than the others, same thing with the original pedal.
You can stack an extra reverse beta stage after it to get more volume.

You're getting tone loss with that stage because the signal is going through two passive filters and then followed by a low gain recovery stage...
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Re: Death by Audio - Apocalypse

Postby johnk » 13 Mar 2017, 05:11

yeah, but not that much volume loss. mine's volume loss is about 1% of the volume of the the other 4 settings.
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