Death by Audio - Soundwave Breakdown  [traced]

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Death by Audio - Soundwave Breakdown

Postby ranjam » 10 Feb 2016, 21:42

I took an old, original death by audio soundwave breakdown pedal in. Very early unit. Very sloppy, high school electronics lab attempt. This pedal just can't make but one good sound at one setting on the controls. And the controls aren't volume or gain. Noooooooooo. Putting B+ on the emiter of each darlington NPN transistor. Very spitty and gated.
I traced it out, I think. For a low parts count, there is a mess to poke through, but here is my best effort.
I have tried to reduce the gain, but it is still just that one setting giving you a bombastic, over-the-top sound; spitty, gated, etc. Any other setting chokes the output worse, and extreme settings have the pedal motorboating. :shock: This can't be normal.
Anyone have real experience with this pedal? Notthe current one you see with six transistors or three knobs. The transistors are in 'backwards', so normal biasing ideas don't work. This is one weird pedal. Thanks in advance, and any help is greatly appreciated.
'You can lead a horticulture, but you can't make her think.'
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Re: Original Soundwave Breakdown: WTF?  [traced]

Postby ranjam » 10 Feb 2016, 23:04

Oops! :oops:
Small error; should be more accurate now!

Image
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Bernardduur (11 Feb 2016, 07:29), Blitz Krieg (11 Feb 2016, 09:30), d312a (12 Feb 2016, 19:09), mirosol (12 Feb 2016, 16:58), modman (14 Feb 2016, 17:32), Zokk (13 Feb 2016, 23:12)
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Re: Original Soundwave Breakdown: WTF?

Postby ranjam » 12 Feb 2016, 00:39

No one has one? There are YouTube videos, and it does sound as spitty and gated as I thought. I did change a couple of resistors, and added one more, to try and tame it down. I think it is modestly tamer, but still crazy. In the PGS demo, it even has the same motorboating with both controls on '0'. :shock:
I have it tamer, as I say, but I doubt I can make it usable for old farts like myself. This is definitely a 'noise' pedal for the younger kids. :P
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Re: Original Soundwave Breakdown: WTF?

Postby Zokk » 12 Feb 2016, 14:02

Yup that's a nice "in your face" squarewave generator :lol:

In the PGS demo they've shown the two trimpots, one for the "input threshold" and the second for the "level" (I assume it's the output level).
Do you have the values for these trimmers please?

edit: or maybe the trimpots are on your schematic, but then the two pots are missing...

Cheers.
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Re: Original Soundwave Breakdown: WTF?

Postby ranjam » 13 Feb 2016, 20:09

No, the schematic I drew is what I have. No printed circuit board, no trim pots. Just a lot of hand wiring to a small perf board floating in mid-air, and 'serial number' of '4'. I thought a lot of the extra wire could make it act weird (capacitance, inductance, etc.), but no such luck. For so few parts, it sure makes a lot of weird noises.
I think I am done with it. With a Strat it is even worse. It seems to need a hot input. With a Les Paul and hot humbuckers it still gates at the end of a note (not much for sustain), and spits as the notes chokes out abruptly. But If sustain isn't a prerequisite for you, just low note riffing sounds like a snarly fuzz. That I could use, but no screaming bent notes on the high 'E' string. There's just not a lot of sustain. You'd never mistake this for a Muff. Maybe a horribly biased Fuzz Face.
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Re: Death by Audio - Soundwave Breakdown

Postby bc108 » 04 May 2017, 21:04

I'm dealing with this... 'thing'?

No succes at all.

Both transistors BCE (collectors to ground).
I used KSP13 (MPSA13), and MPSA29 (Hfe around 10.000).

Nothing happen: sounds really HORRIBLE
When Bias is fully closed (no k's at all), the Collector of Q2 eat a LOT!.
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Re: Death by Audio - Soundwave Breakdown

Postby toneman » 05 May 2017, 02:06

IIRC, NPN transistors have positive on collector.
(the "arrow" points AWAY from the base)
the schematic has this reversed.

Learning About Electronics:
http://www.learningaboutelectronics.com ... transistor

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Re: Death by Audio - Soundwave Breakdown

Postby jrfox92 » 05 May 2017, 06:31

What? [smilie=a_huh.gif]
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Re: Death by Audio - Soundwave Breakdown

Postby Nocentelli » 05 May 2017, 21:10

toneman wrote:IIRC, NPN transistors have positive on collector.
(the "arrow" points AWAY from the base)
the schematic has this reversed.

Learning About Electronics:
http://www.learningaboutelectronics.com ... transistor

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toneman, meet death by audio; death by audio, meet toneman.
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