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Monday, 6 January 2014

Bipolar Voltage Converter

This will be a useful little circuit for anyone wanting voltage doubling and negative voltage from a single charge pump.  I've done this with a particular layout in mind, but I think it may come in handy for a few effects that require +/- supplies, which can now be accommodated with a small daughterboard.

I don't know if this will work with our more commonly used ICL7660S although the pinout does appear to be the same.  The schematic called for LT1054 which are more expensive, but I only paid about £5 for 5 on eBay a while ago and so they can still be had for a reasonable price without being fleeced too much.  If you do want to try the ICL7660S then it may be worth omitting the cut between pins 1 and 8 to enable the frequency boost so you don't get noise.  The LT1054's oscillator typically runs at 25kHz.

Using the 1N5817 diodes shown should give you around +/-17V, but if an effect calls for +/-15V then you could always opt for using 1N4001 diodes instead.  The extra voltage drop will get you closer to 15V.


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49 comments:

  1. Unknown6 January 2014 at 21:22

    Could I run a 12v into this and get +/-24v out?

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    1. IvIark6 January 2014 at 21:29

      You can have up to a 15V input with the LT1054. If you put 12V in you'll get about +/-23V out ish.

      If you try the ICL7660S it has a maximum input voltage of 12V so I wouldn't risk that one.

      Delete
  2. Unknown6 January 2014 at 22:11

    Would the higher voltage work well with a tonebender mkII?

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    1. Unknown6 January 2014 at 22:13

      I am building a tonebender as I type this.

      Delete
    2. IvIark6 January 2014 at 22:18

      I can't see too much benefit from running a Tonebender at a higher voltage. The last thing I'd want from one is more headroom and less fuzz.

      Delete
    3. Unknown7 January 2014 at 04:29

      Thanks. I am still fairly new at building and am not when a pedal would benefit from higher voltage or when it would take away from it like in this case. I really appreciate all the information that you and many others post on here. I am learning so much. What started as simple mod to my old Daddy-O pedal, has turned into a full-blown addictive hobby.

      Delete
    4. IvIark7 January 2014 at 11:54

      IC based pedals can benefit from the wider voltage swing because it can give them much more head room and so it will stay cleaner for longer. Something which isn't going to be a desired response for pedals that are designed to be dirty like a fuzz.

      People who like and use low gain overdrive pedals can find this very attractive because the effects tend to be more dynamic and can give more of a boost before the dirt kicks in, but personally I play Iron Maiden and Metallica and so am never too bothered about it :o)

      Delete
  3. Ross6 January 2014 at 23:50

    ICL7660 and TC1044SCPA are pin-compatible with the LT1054, just leave out the cut between pins 1 and 8.
    Thanks for doing this, I have plenty of boards that could use +/-17V.

    ReplyDelete
  4. Unknown8 January 2014 at 08:19

    Mark,
    I built the BK Butler Blue Tube Driver but Harold Sabro's Version as per this Link.

    http://www.sabrotone.com/?p=3055

    There is in "Request Forum - BK Butler" a Post by John Kallas and what he did to quiet this AC Powered pedal.

    I would Like to use your Bipolar Voltage Convertor on Harald Sabro's Build, but I dont know where to put ~-17V(negative) connection on the Board. ??? Any Idea??? I don't normally Build Pedals that Use AC Power Supplies and don't like the noise/hum I am getting with the normal AC Power Supply. Thanks.

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    1. IvIark8 March 2014 at 22:51

      Sorry Jon I missed this post, did you get sorted out?

      Delete
  5. Jimijam24 January 2014 at 14:11

    Does the ICL7660SCPAZ work as well? I see those pretty cheap on the ebay

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    1. IvIark24 January 2014 at 14:24

      Yes, the ICL7660S is the important bit. The suffix just denote things like package type (DIP8 or SOIC) and the temperature range. So as long is it's DIP8 I wouldn't worry about anything else.

      Delete
  6. Jimijam24 January 2014 at 17:47

    ones I see are ICL7760CPAZ - mouser has output voltage at 1.5 V to - 12 V, 1.5 V to 18.6 V

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    1. IvIark25 January 2014 at 13:30

      No you need the ICL7660S****. If you get the one without the S it has a lower frequency oscillator in the audio range and your pedal will very likely squeal.

      Delete
    2. Jimijam27 January 2014 at 16:01

      Yeah that it does :( off to get the ICL7660S****...

      Delete
  7. Murch24 March 2014 at 02:42

    So I'm planning to build a fuzz face (with voltage sag down to zero) using this, and was wondering how the grounding works. Does it just share the original ground, or use the positive out as the new ground?

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    1. Dave24 March 2014 at 08:37

      Why are you using this for a fuzzface? A normal fuzz face will run off 9v so you dont need bipolar power supply.
      Cheers
      Dave

      Delete
    2. IvIark24 March 2014 at 10:44

      I agree, you wouldn't need this, just the Negative Voltage Inverter to get the -9V. And yes ground is the same throughout the pedal, check out this layout:

      http://tagboardeffects.blogspot.com/2010/11/fuzz-face-pnp-negative-ground-with.html

      Delete
    3. Murch25 March 2014 at 02:52

      I wanted to try extra voltage in addition to the lower ones, essentially giving me a range of 18 to 0. Using this would be a lot easier than adding a second charge pump.

      Delete
  8. hangingmonkey16 September 2014 at 10:25

    Im thinking about using this to power a PLL, any diode suggestions to get +/-12v or should I just use a trimmer?

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    1. Jacob13 May 2015 at 18:38

      I have the same issue, would love to see a layout for +/-15v and +/-12v from one negative ground 9v source using a LT1054.

      Pretty please? :)

      Delete
    2. Unknown23 July 2015 at 21:08

      I dig this! A question though. I'm using this to power a mic preamp to run vocals to a guitar pedal. What happens is that when I use the same 9v to power the preamp and pedals the preamp shuts down. When I use different 9 v power supplies they both work. Is there a mod to make it so one 9 v can power the bipolar and single power supplies? Thanks

      Delete
  9. Unknown12 February 2016 at 15:39

    Weird... I built this one with 1N4001s, but still get -17 and +17v readings. Any idea's you to trim it down to 15?

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    1. brotherleech15 March 2016 at 06:49

      If you didnt manage to sort this, there is a solution on the layout of the Rusty Box on this site. I had the same problem yesterday

      Delete
    2. Unknown29 May 2017 at 22:16

      What was the solution brotherleech? Is it to just use the power supply from the Rusty Box or were there components that needed swapping etc?

      Delete
    3. Unknown24 August 2021 at 10:44

      use a 7815 and 7915 chip

      Delete
  10. Unknown17 April 2016 at 16:26

    How can I do to reach 30v? Can I add the -15v to +15v or what?

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    1. mirosol18 April 2016 at 08:04

      Just curious, where you plan to use the 30V supply?

      Common method is to use -17V on dual opamp pin 4 and +18V on pin 8. This way the IC sees 34 volts as its supply voltage.
      +m

      Delete
  11. Unknown24 June 2016 at 08:20

    I'm interested in building the Sunn Beta circuit that's on here and I see it requires 15v power. If I understand correctly, this should definitely be my solution to powering it from a standard 9v power supply, but how much power do you think this specific circuit will draw? I plan on making this a stomp box and adding it to my board which currently has a Voodoo Lab ISO 5 power supply. Can I power this with one of my 100mA outputs, or would I need to use my 400mA? Or am I going to have to get my hands on another power supply? I'm kinda lost here.

    Thanks!

    ReplyDelete
  12. Blue Brown5 August 2016 at 04:25

    Can this be modified to output +17 and -9v? The reason I ask is that I have an old Roland SH101 synth, which used (a now unobtainable) DC coil converter to produce +18v and -9v from a single 9v plug pack. A circuit like this would be ideal to replicate desired voltages!

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    1. IvIark6 August 2016 at 12:26

      Pin 5 of the IC gives you the supply voltage inverted and so should be at -9V. You can omit D1, D2, D3 and the bottom left 100u cap as well along with the 10u a few rows above it.

      Removing those components means you should be able to shave a few rows off the layout as well if you want to save a bit of space. Just move the lower ground connection one row up to the now unused row, and omit the bottom 2 rows completely.

      Delete
    2. IvIark6 August 2016 at 12:29

      One thing to bear in mind is you're limited to a 100mA output current, so you will want to check the requirement of the SH101. Put more circuits in parallel if more current is required.

      Delete
    3. Blue Brown7 August 2016 at 01:30

      Thanks for that. I guessed that would be possible once I had a look at the datasheet. Still trying to find out current draw for those parts of the SH-101 circuit but I'm pretty sure it's well under 100mA.

      Delete
  13. Bruno24 February 2017 at 12:43

    doesn't it have a "virtual ground" ?(or have i just to use the original ground?)

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  14. Grinding Teeth Distro2 September 2017 at 22:53

    Hi, was looking at building this for the Sunn Beta Preamp. Is there any benefit of using 7815 and 7915 to regulate the +/-17V at 15V? Also the 7815 etc datasheets nominate input voltage at 23V, anyway of tweaking circuit to that, if regulators are required. Cheers, Chris.

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    1. RankoT3 December 2017 at 09:58

      78xx series regulators dropout voltage is 2V, so technically you could, but you can achieve that with simple diode choice.

      Delete
  15. Nick James4 December 2017 at 14:01

    Hi. I'm going to build a Boss CE-1 and I need +/-14v. You said by using 1N4001 we could get 15v. Would it be wise to try other diodes to see if I can get the 14v?

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  16. ISPITNAPALM6 November 2018 at 17:27

    I was building the sunn beta but my 1054 gets very hot.. about 60 degrees Celsius. Who else can say that about his charge pump in combination with the sunn beta ? Does the ICL7660 provide more current?

    ReplyDelete
  17. Unknown20 November 2018 at 18:56

    Hi,
    Can I use this to daisy chain the ESR Graphic Fuzz ( https://www.diystompboxes.com/smfforum/index.php?topic=83300.20 )
    with the +/-9v and ground ?

    ReplyDelete
  18. tep17 May 2019 at 17:21

    I'm not getting it : how to measure the voltage ? I just built it and I et : 8.3V from [ground] to [+17v], and nothing from [ground] to [-17v]... Am i missing something ?

    ReplyDelete
  19. volfied16 March 2020 at 14:13

    I'm having the same problem. Basically, even though everything is wired up correctly, the output is exactly the same as if the IC wasn't even there. I get 8.7V output from 9V input.

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    1. volfied17 March 2020 at 12:42

      Well, I found a couple places where the solder had overflowed the strip and fixed them. Oddly now, even though I used 4001's, I'm getting 17V. Was hoping for 18V.

      Delete
    2. volfied17 March 2020 at 12:43

      Sorry. Was hoping for *15V*.

      Delete
    3. IvIark19 March 2020 at 00:09

      Use a 15V voltage regulator at the 17V output. The regulators just have 3 pins, input (17V), output (15V) and ground so you could just add a little 3 row vero daughterboard which would be tiny.

      Delete
  20. volfied20 March 2020 at 16:43

    Thanks, lvlark! Actually, Stack Exchange got me the answer, which is that I was testing on a multimeter, rather than in a real-world context. Hooked up, it provides about 16V, which is correct in this context.

    ReplyDelete
  21. strangeloop30 October 2022 at 20:15

    *Knock Knock*… if anyone is still out there, I have a little issue that could use some expert brainpower:
    So, I just finished building this guy using the 1054 bipolar voltage converter and overall the circuit sounds incredible, BUT I have a constant 7K-ish whine that just won't go away.
    I discerned, by accident, that running a jumper between lugs 1 and 4, and another between lugs 3 and 6 of the "drive" pot greatly reduces the volume of said noise. Now, if I hold the Drive pot in my hand while putting a fair amount of pressure on lugs 1,3,4,6, the noise disappears completely (This makes it difficult to play anything meaningful, unfortunately) and the circuit sounds great.
    Increasing the Drive pot certainly increases the noise, as does using the Treble pot. The pedal is definitely playable, but it would be great if I could get that noise to go away… is it the LT1054? Is it the board itself?

    Lastly, I use a Strat w/ EMG active pickups, so is it possible that this is a more or less normal amount of noise that my guitar is blowing out of proportion… or should I maybe go into my interface at Line level when using the Sunn Beta? So many questions!!

    I am not yet smart enough to figure it out on my own and I could really use YOUR help! ;)

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    1. Tom31 October 2022 at 00:50

      I actually received a bad 1054 from Musikding a while back. I ordered another from a different place (probably Smallbear), and the noise all but disappeared. The 1054 is supposed to be the most stable and silent of the bunch but it isn't perfect, that's for sure. You could try a 1044 in its place and create a temporary jump between pins 1 and 8 to troubleshoot.

      Delete
    2. strangeloop31 October 2022 at 01:48

      Thanks, Tom! I will give the 1044 a shot.

      This post was actually meant to go onto the "Sunn Beta Preamp' layout page, but I forgot to click over to the correct tab, so off to repost there…

      Thanks again!

      Delete
  22. jackzaps10 November 2022 at 23:02

    Can you publish the schematic? it's tedious to try and reverse engineer this layout for uses other than stripboard. thanks.

    ReplyDelete