Tuesday, 7 January 2014

Providence Stampede OD SOV-2


And this is the one I did the bipolar voltage converter for! :o)

This pedal uses a 9V supply which is then converted to +/-15V using a 5V regulator into an expensive NMA0515SC 5V to +/-15V converter, plus a couple of inductors which is another unusual component for us to use.  So I preferred the idea of using components I was more familiar with and which could be obtained at a lower cost and in any quantity.

So you're going to need the bipolar converter layout I did from yesterday.  This will take you a bit above the +/-15V used by the original which may give you a little more headroom, but if you want to drop it a bit further consider putting a polarity protection diode in series with the 9V supply to the charge pump.  That will drop the voltage around 0.7V before conversion to get things a bit lower.  I think if you do that and use 1N4001 instead of 1N5817 in the charge pump you'll be very close to the required number.  Or just have a bit of extra headroom, it's up to you.




You can either make it all on one board, or I reckon it would be easier to keep the converter on a separate daughter board which can be tucked away somewhere in the box.

The diodes are unknown, here is a pic posted by Olof who posted the schematic on Freestompboxes if anyone has any ideas:


It has been suggested that the red and blue one may be a 1S1588, which I think is one of the unobtainium diodes in the Analogman King of Tone.  And the other has been suggested to be a 1N4249.  If you can get them to try then all the better, if not then just use a 1N4148 and 1N4001 combination which I'm sure will get you 99% there if not all the way.  Or experiment and let us all know how it turns out! :o)

Manufacturers description:

A wide dynamic range of overdrive sounds.
The Providence SOV-2 Stampede OD pedal is designed to deliver natural overdrive without obscuring the inherent characteristics and tone of the guitar being used. It features a special bipolar power supply that powers the internal circuitry with boosted voltage, providing a wider dynamic range than possible with conventional 9-volt powered overdrives. For singing lead tones and solid, chunky rhythms, there's nothing like the SOV-2 Stampede OD.







46 comments:

  1. Nice! I was just asked if I was able to clone this like a week ago. I've got way too many projects on my hands to try and confirm this at the moment so I'll just wait it out.

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  2. Good call on this one. That is one tasty sounding circuit. I think my wife has figured out where all my free time is going. And she wants to have a word with both Mark and Misosol. oops.

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    1. Yeah, mine isn't too happy about it either :o)

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    2. Problem solved here, I'm divorcing

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    3. The trouble with DIY fetish and rock musicians in general is that divorce doesn't really change anything.

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  3. This pedal sounds AWESOME !!! Really nice raunch crunch !
    Is this a new design or some variation on a different pedal?

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    1. It isn't a direct copy of anything but you can see where it comes from. The TS808 is:

      Transistor buffer > gain stage with clipping diodes in feedback loop > tone stage > transistor buffer

      This is:

      Opamp buffer > gain stage with clipping diodes in feedback loop > tone stage > opamp recovery stage

      The main gain and tone stages are very similar to the TS808. But then there's only so many ways you can do it with opamps and most were probably first published in a datasheet by the Japan Radio Company first. I think it would be fair to say that you can see where the inspiration comes from though.

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  4. If you're ordering stuff from mouser, they have the LT1054 for less than $3 each

    Mouser Part #: 595-LT1054IP

    http://www.mouser.com/ProductDetail/Texas-Instruments/LT1054IP/?qs=sGAEpiMZZMtitjHzVIkrqfSWpcWTPe%252bSNc10CtLc4Cw%3d

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  5. Cool!

    I was just about to suggest that the grey round one is a Zener of some kind, Perhaps a 12v? I'm not sure, but I have a bunch of diodes in my basement that look just like that and are 12v Zeners. I agree with the blue-striped one being a 1588.

    May have to try this at some point...

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    1. I could be a zener I really don't know, but if you have some that look like that then I'd definitely try them! :o)
      Any zener voltage would work fine, it's the forward voltage that matters here rather than the breakdown voltage.

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  6. not part of the circuit but what is up with the clip around the footswitch on the pedal? Protection? or a fancy version of a 'belt buckle' for Hawse?

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  7. Is there away to power it direct 9v? Pls teach me

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    1. The only way you could do it would be to connect 9V to the +15V connection, ground to the -15V connection and instead of the shown ground connection, create a half supply reference voltage. That will only give you a voltage swing of 9V though instead of 30V and so it will be quite far removed from the original with nothing like as much headroom.

      Personally if I wanted to simplify it further, I'd go for +/-9V connections using the simple voltage inverter here:

      http://tagboardeffects.blogspot.co.uk/2012/05/negative-voltage-inverter.html

      It may still not be quite the same but it would be a lot closer with an 18V swing than just 9V and the required addon daughterboard is very small and simple.

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  8. Replies
    1. Built it, housed it, plugged it in. Smell of toasted components filled the air. Will breadboard at the the first opportunity to see what gives...

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    2. Thanks for the feedback. Will you measure the voltages you're getting from charge pump board, if that one isn't working the main effect board won't either, so may as well get that one out of the way first :o)

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  9. Alrighty. I'm waiting for the diodes at the moment. Gonna shoot for it.

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  10. I built the converter up. I'm gettin 9.38v from the PSU and 19,2 volts out from the board. That's gonna be too much, right? I can't find anything wrong with my build thoudh. Anyone else tried measuring it?

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    1. ..might be an explanation to the fried component smell here.

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    2. It's certainly a strong possibility. The JRC4558 is only rated for +/-18V so that may be high enough to cause it problems. What voltage are you getting at the -17V side?

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    3. I used a LED in series with the 9 Volts at the input. It works fine.

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  11. Getting -18,3 at the -17V side.

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    1. Probably not too bad then, it's less than a 36 volt swing but I'd still be tempted to put a 1N4001 in series with the supply to it so drop it a little more. Are all the electrolytics in the right way. Positive side to ground from the -15V connection?

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    2. Yes, they are. I actually corrected a few of them. I was tired and put some of them the wrong way around. That resulted in a pumping voltage that didn't seem very good. Now the positive side is still a little bit unstable. When I measure it - it starts from 19.52 and slowly drops to 19.20. And when I take the leads off and measure again, same thing. The slide was so small I didn't worry about it but now that I say it aloud, is that bad? Maybe trouble with the caps? I triple quadruple checked them though. Can't find anything wrong unless one of them has gone bad. I've got loads 1N4001's, might try that tomorrow when I've got more time.

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  12. 1N4001 in series certainly helped. 8,77V going into the charge pump after the diode. +18V coming out. Still a little bit uncomfortable with it but I think this will do for now. Gonna build the main board next week and take a shot.

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    1. Ah screw it, I put another before it. Now it's around 16,3V. That'll do the trick. I'll report how it goes.

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  13. Oh, well. I'm not all that good with waiting. I used some huge ass electrolytic leftovers to finish and test this mofo. It works with first shot but I gotta say that my first impression (with headphones though) is that I DO NOT like this thing. It's so gritty and gnarly and fuzzy - not used to stuff like this. The distortion is pretty spongy and all over the place but after checking the demos I'm fairly confident the layout is right. It sounds pretty much like them. Like an overbiased EL84 amp driven to it's limit is how I would describe it. Some people like that stuff - I'm not that much into it. The gain pot at minimum is below unity though, what might that be about? Not a big deal but in the demo it looks like zero is at unity and clean boost.

    It's definitely pretty unique in character. I gotta play this thing tomorrow without my headphones and see if I get used to it.

    However, I think you can tag this one. Or wait for tomorrow after I post what I've heard with decent volume and speakers. I think the charge pump needs some work though. Feeding exactly 9V into it provided too much voltage out. Putting a 1N4001 between the PSU and the charge pump input will save the day, I had to use two as I mentioned earlier. Would've worked with one I guess.

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    1. Awesome, top man! :o)

      I don't think it should be below unity at the far counter clockwise position though. The 10K resistor at the Drive 2 and 3 connection sets the minimum gain and so even fully counter clockwise you should still be getting a gain of 2x. I'll hold of tagging until tomorrow and then we can see how it performs at volume.

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    2. Oh and it's just occurred to me, thanks for verifying the bipolar converter too, just noticed that hadn't been verified :o)

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  14. Uh, ok. Forget everything I just said. It was the headphones. This is a very tasty sounding overdrive. Midrangey and growly. Maybe a little bit tube screamerish in the mids mids but it has more headroom and it doesn't comrpess as much. This could replace a TS as a roots/blues whatever pedal because of that. Will work VERY GOOD (tried with my blackstar) boosting a distorted Marshall with gain in the lower end of the taper and volume dimed. Also, I think I was wrong about the gain pot. With gain at minimum the volume still goes past unity in the lower end of the taper. The volume rise is just so in your face as you open the gain pot like 10% that it confused me. But it's not BELOW unity fully counter clockwise either.

    Tag the son of a bitch!

    And no problem, thank you for the layouts mate! ;)

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    1. Oh, and I used the 1N4148 / 1N4001 combo. I think there was pretty much straight up +15v goin into the pin 8 of the 4558's. Pin 4 was around -14v I think.

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    2. Excellent, glad it's working better for you now. It shall be tagged! :o)

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  15. hello.....

    I rode this "Bipolar Voltage Converter to get +15 / -15 more is much higher than 17v and I've checked everything.

    I am using LT1054 with my source at 9.43v project is giving +19.30+ / -18.45

    I put the two 1N4001 in series in the supply 9v in and now works slightly better +15.91 / -18.45

    how I can improve this?
    thanks

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    1. You could take out the 1N4001 in series to get the maximum voltage from it, and use a 78L15 and a 79L15 regulator to get exactly +/- 15V

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  16. Hello Iviark,
    where I can put the 3 connections of 78L15 regulator on the layout to have exactly +/-15V ?
    Thanks

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    1. For the 78L15
      ~+17V to input
      Ground
      +15V output to SOV

      For the 79L15
      ~ -17V to input
      Ground
      -15V output to SOV

      I'd put the regulators on a small daughterboard to simplify it

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    2. Thank you very much, Iviark !

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  17. i think value of resister both on output buffer is wrong.
    it's 1K, not 10K.
    becouse sound is not clear.
    it's a clear distinction between original and diy.

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  18. I have to tackle this one - is the best result here to set this up with 78L15 regulators on another daughterboard to get the correct voltage?

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  19. First let me say how much i love this blog and the great work you do
    That said, i can't get this to work :-P
    I can't see any layout error, the charge pump is working flawlessly and still i get a short circuit when i plug the power in
    Voltages are +17,3 - 16.4, wich, i guess, is good enough
    Ic's are good, diodes and caps are in the right directions in the main board (there are no diode besides the clipping ones, so this isn't really an issue... )
    Any ideas?
    Maybe the ground network needs some odd configuration?
    Having done many hundreds of builds, i really can't tell what is wrong whit this one.
    I'm pretty frustrated!

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  20. Hey there....
    May I run this on 18 v and put a 15 v regulator on a separate board? Thnx

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  21. Also, do those caps need be more than 16v?

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