Friday, 11 April 2014

Death By Audio Sound Saw

I would advise caution before you proceed :o)

This has been put together after a request, but it's based on a schematic of unknown origin so I don't know whether the scheme even works never mind the layout.

A couple of things do make me think it could be a good trace though.  The volume pots are wired in an unusual way which I have seen from DBA before, although for this layout I have changed them to the more usual volume pot configuration that we are used to, purely to remove unnecessary daisy chaining and so make connections simpler - their functionality in the circuit remains identical.  It also looks like a mish mash rats nest of a circuit, which again points to authentic Death By Audio :o) (just joking guys).

As this is a gamble at this stage, it may be one to do with pots in a breadboard first rather than soldering them, but as long as you know the score from the outset, if it's something you want then please let us know so we can verify the scheme and layout or bin the post entirely.

Update 12th April: Now corrected and verified so no longer a gamble :o)

Here is the schematic it is based on for those who may want to follow it




The pot numbering shown in the schematic is the reverse of the convention and so I have swapped lugs 1 and 3 where necessary.  As noted above the volume pot connections have been altered to our usual:

Volume 1 ground
Volume 2 output
Volume 3 input

Only the second stomp switch connections are shown in the layout.  The main bypass stomp switch is wired as per usual, and with a separate LED to show when bypassed.  Then the LED mentioned in the layout (assuming using bi-colour) displays the selected channel.

One of the LED resistors was shown as 100K which seems huge to me even for a ultra bright LED, so I've just included a single 3K3 resistor for current limiting, which can be used for a common anode bi-colour LEDs with stomp 2 switching the ground connections.

Anyway, enough waffle, here's the info about the original:

trash the system. make your fuzz pedal kill, kill, kill. everyone will scream in terror. here is the SOUND SAW. 2 unique channels of huge thick quasi-eq filters to intensify your wall of sound. blast your way out of the mix and sound enormous. the one channel of the SOUND SAW cuts a selectable frequency and boosts the hell out of the frequencies around it while the other is an active bass to treble blaster. LED of selected engaged filter dims when bypassed to let you know which channel is active. the SOUND SAW is capable of nice creamy tones or huge amounts of boosting, feedback insanity, cutting, sub woofing, room shaking, glass breaking frequencies to make you have the most intense sound possible.

Sound Samples:






33 comments:

  1. Sounds great, I'll give one a go when I get the time.
    Cheers
    Dave

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  2. If you build this I'd recommend socketing the 22n cap at the Stomp 2-6 connection. Checking the values I've read that wrong but am not sure if it's 220pf or 220nf. It looks like pf to me but I would expect that to cut a lot of low end and so I think socketing that position and trying all the values may be a good idea.

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    1. In the meantime I've swapped it to 220p which I do think looks like the noted value, but I'd still socket.

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  3. built it today but it's not working. so far, it has an extremely low output (it's barely audible) and the filter controls are doing nothing.

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    1. Is the fuzz section workin in it's own, if you connect the input to the stomp 2-5 connection to bypass the filters?

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    2. there actually is no fuzz section, it's just two filters. I got the filters kinda working but the output is still extremely low. i'm going to put it on my scope and trace the signal to see what's actually going on.

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    3. The filters go into the fuzz section. The parts at the bottom should be providing the fuzz

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    4. nope. there definitely isn't any fuzz in this circuit. jushe fuzz that you hear in the demo clips are the fuzzes that they're running in front of it. I got it working perfectly now. all I had to do was rotate the transistors (2N5088's) 180 degress from your layout. and the 'mystery cap' is indeed a 220P so no need to socket it (although I did socket it in mine for testing purposes).

      rotate the transistor symbols and pinouts 180 degrees and then verify it! all I can figure is that the guy that drew up the schematic must've got the pinouts wrong on the 2N5088 transistors. DBA seems to be running the collectors to ground instead of the emitters like in most pedals (which is kinda typical for him). it works perfect that way.

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    5. Awesome nice one mate. I'm in the pub at the moment but i'll correct it tomorrow when I sober up :o)

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    6. Layout and schematic corrected and tagged. Thanks John :o)

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  4. Hi there, probably a dumb question, but I'm a bit confused by the led-wiring..

    For what I understand, the led for the bypass is wired as usual and isn't mentioned in the vero at all?

    So for the channel switching (which I guess is what switch 2 does) I see 2 anodes and 2 cathodes. Does this mean that the channel switching stomp has 2 leds, which makes the total leds for this pedal 3?

    Or.. Do I use a 'normal' led for stomp 1 and a bi-color led for stomp 2/channel switching? In that case: I can explain the 2 anodes from the bi-color leds coming from the vero, but i'm a bit lost with the cathode. On a bi-color led I thought there were 3 leads, 1 of them a cathode. Should I split this lead in 2 wires, 1 going to stomp 2-7 and 1 to 2-9? Or am I totally misunderstanding this?

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  5. I tried using a bi color led myself but it didn't work so I just hooked up one led to 2-9 so i could differentiate which channel is on.

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    1. Thanks! I'll probably go that route as well...

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  6. Been ripping my hair out over this guy all night. I can't seem to get any signal to pass hardly when the effect is engaged. I flipped the transistors with no avail. They are currently seated as they are in the vero layout, and I can JUST barely hear the signal going through when my amp is cranked and the filter knobs are at zero with the volume knobs dimed. I've gone over my wiring and the board about 5 times now and I don't see any faults. Any ideas?

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    1. Is it one or both channels you are having this problem? Could be a bad component somewhere.
      Cheers
      Dave

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    2. Both channels, unfortunately. I can at least get a TINY bit of signal with the transistors the right way, but that's about it. I'll have to look into it some more

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    3. This comment has been removed by the author.

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    4. So I rebuilt the vero layout, and I'm still not getting any sound with the effect on. I've checked my vero layout 4x over, as well as my off board wiring and I'm baffled. I did the 2-5 to input and got some fuzzy sounds, but when I put 2-5 back onto the lug of the second footswitch I get no sound.

      Would anyone care to take a shot of theirs or draw up a wiring diagram?

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    5. it's not supposed to get fuzzy sounds at all so something's not right. the circuit two different tone controls ("huge thick quasi-eq filters").

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    6. maybe this will help you:

      http://johnkvintageguitars.homestead.com/Effects/others/DBASoundSaw/DBASoundSawWiring.png

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    7. John- your layout differs from the posted layout in terms of the vero- going to mirror my board to yours and see if I can coax it to life. All of my wiring checks out with yours otherwise!

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    8. Just adjusted my layout to mirror yours and still nothing. I'm really stumped here, it seems like a pretty simple build.

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    9. i'm not sure what you're taslking about regarding mirroring IvIark's layout. I think that they're the same. if you're still having problems after wiring it like my diagram then you have an error in your build somewhere.

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    10. In the image you posted of your wiring diagram, I also tried adjusting my vero layout to match yours, there are subtle differences between your vero layout in the wiring image and IvLark's layout. I've tried both IvLark's layout (x2) and yours (sans 4.7uf cap, moving the .47uf cap down and 10k resistor on Q2 down a row) both to no avail.

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    11. i've since updated it to match IvIark's. there were a few errors in mine .i previously built it exactly like it's shown now and it works perfectly.

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  7. Thinking I would like the Bi-color led. Plus would like to understand it. Can someone explain the wiring of leds in this schematic? I just can't seem to get my head around it..

    Channel led + and bypass led+.. Is this the same led? Cause in the description is mentioned that for the bypass switch it is wired as usual, with a separate led.

    So.. for the second led I see 2 times +, coming from the vero.
    And from the same led I have 2 times - going to the switch...

    That is four in total. I know that can't be right. It's probably the language barrier, but I just can't understand..

    Sorry to keep bothering you, i tried searching, but Everywhere I go, I see a led with 2x+ and 1x-...

    What do I do wrong?

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    1. Those LEDs are separate. One is an indication for the main on/off of the effect, and the other is an indication for what "channel" is selected the the second stomp.

      You will link the Bypass LED+ wire to the anode of the bypass LED. The cathode then goes to the switch and is grounded through the switch when the effect is turned on, which in turn illuminates the LED (as per the offboard layout diagram).

      The Channel LED+ goes to the anode of a bi-colour LED. One cathode goes to lug 7 of the stomp, the other cathode goes to lug 9, and lug 8 is grounded. Then one stomp will turn one colour of the LED on, the next stomp will turn on the second colour, and it will cycle like that. You need to make sure the Bi LED you buy has a common anode for this to work as described.

      If you'd prefer to just have the bi-colour LED and use it for both channel and on/off indication, then just ignore the bypass LED on the main on/off stomp, omit the ground link wires between lugs 2 & 3 and 3 & 6, and instead take the Channel LED+ wire to lug 1 of the main bypass stomp, with lug 2 then going to the common anode of the bi-colour LED (then the cathodes of the bi-colour going to the second stomp as described above). Then the second "Channel" stomp will still change the colour of the LED, but it will only be illuminated (in either colour) when the effect is on.

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    2. Looking at a picture of the original pedal would have helped you visualise what is happening in the layout:
      http://medias.audiofanzine.com/images/normal/death-by-audio-sound-saw-146436.jpg

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    3. Thanks for your comment, I think I understand correctly now.
      I have seen the pedal, but the connections I probably misread.

      Because of the comment that stated that the switch and led for bypass were wired normally, I thought that the Bypass LED+ was something different. Now I understand that the LED is wired to the switch and the vero, instead of the powersupply.

      That and the - and plus of the LED threw me off. In my (too) simple mind, Cathode was - and Anode was +.
      I bought a LED which says the outer 2 are red and blue, and the middle 'lug' is -. Therefore I thought: A bi-color LED has 2x "+" and 1x"-".

      I will wire it the way you explained. I'll let you know the outcome.


      Again, thanks so much!

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    4. If the middle lug is marked "-" then it is a common cathode, not common anode. You can still use it but you need to connect lug 8 of the stomp to 9V instead of ground, and the Channel LED resistor needs to connect to ground instead of 9V (just take the bottom lead of the 3K3 one row lower). Then you take the other side of the LED resistor to the centre common cathode.

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  8. Wow, awesome. I'm starting to get it, thanks! I the webshop I order, common cathode or anode isn't even an option. I thought there wasn't a difference.
    Thanks a lot, things seem to get into my thick skull eventually ;-)

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  9. if you have problems getting sound from this (levels are very low), change the 10k resistors from the emitters to 9v. i put trimmers there and set them around 4,7k. could be less and it'll work fine.

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  10. I just finished building mine and I'm getting a pretty loud pop from the "channel" switch. I've tried pull down resistors and replacing the switch. I also tried removing the LEDs from the "channel" switch and that made no difference. Any Ideas?

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