Stupid Power Question (Positive Ground)

Frequently asked questions regarding powering your pedal.

Stupid Power Question (Positive Ground)

Postby joinpobob » 06 Oct 2011, 18:13

I built a FF clone and an Octavia clone and housed them in one box. The circuits themselves require a positive ground. I had been using a MAX1044 to invert the power from my power source that is also connected to negative grounded pedals.

But, I have now blown two MAX1044's. (Nothing noticeably blown, but the circuits don't work. But when I replace the chip with a new MAX1044 it works again.) Q1: Any tips on correctly wiring a MAX1044? Is there anything specific I need to do to prevent static discharge or something?

In any event, I am considering building a Dallas Rangemaster clone and a PNP Big Muff, both with Positive Grounds. So, I have been contemplating the use of a stand-alone poer supply for all my positively ground pedals. (I would plan to use a 1Spot power adapter.) Q2: If I use a 1Spot and only daisy-chain it to Positive Ground pedals (FF, Octavio, D Rangemaster, and Big Muff), can I just hook reverse all of the power jacks to supply a positive ground? Would that work?

I think it makes sense, that the 1Spot gets its power off of a transformer, so the power is reversible and there is no other common ground connection to the other pedals (being supplied by a different power source). But before I hooked this up and blew all my pedals, I figured I would ask.

From what I can gather, the only real drawback would be that using two power supplies with multiple daisy-chains could get confusing and I could accidentally plug the wrong supply into a pedal. I plan on marking all of the positive ground daisy chain connections with red electrical tape to avoid confusion.

Thanks.
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Re: Stupid Power Question (Positive Ground)

Postby Barcode » 06 Oct 2011, 20:10

joinpobob wrote:I built a FF clone and an Octavia clone and housed them in one box. The circuits themselves require a positive ground. I had been using a MAX1044 to invert the power from my power source that is also connected to negative grounded pedals.

But, I have now blown two MAX1044's. (Nothing noticeably blown, but the circuits don't work. But when I replace the chip with a new MAX1044 it works again.) Q1: Any tips on correctly wiring a MAX1044? Is there anything specific I need to do to prevent static discharge or something?


I don't recall how much current the Octavia pulls, but it could be that you are exceeding the current limitations of the chip. MAX1044 chips really are better suited to power a single unit or a couple of circuits that have MINISCULE current draw. The LT1054 is a suitable replacement that has a higher current rating.

In any event, I am considering building a Dallas Rangemaster clone and a PNP Big Muff, both with Positive Grounds. So, I have been contemplating the use of a stand-alone poer supply for all my positively ground pedals. (I would plan to use a 1Spot power adapter.) Q2: If I use a 1Spot and only daisy-chain it to Positive Ground pedals (FF, Octavio, D Rangemaster, and Big Muff), can I just hook reverse all of the power jacks to supply a positive ground? Would that work?

I think it makes sense, that the 1Spot gets its power off of a transformer, so the power is reversible and there is no other common ground connection to the other pedals (being supplied by a different power source). But before I hooked this up and blew all my pedals, I figured I would ask.

From what I can gather, the only real drawback would be that using two power supplies with multiple daisy-chains could get confusing and I could accidentally plug the wrong supply into a pedal. I plan on marking all of the positive ground daisy chain connections with red electrical tape to avoid confusion.

Thanks.


Yes, this is true. I would definitely recommend against it though. I once built a power distributor using multiple 1044 chips (before I discovered the LT1054) as a breakout box for all my positive ground effects. That way, I could just daisy chain with one power supply (the One Spot will have no current problems for about a couple dozen average pedals) to all the negative ground effects and my "converter box," then run a tap from each 1044 in the converter box to a separate positive ground pedal. Worked great.
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Re: Stupid Power Question (Positive Ground)

Postby joinpobob » 07 Oct 2011, 22:09

Thanks for the info!

I have a few LT1054 (I think). I will give them a try.

Why do you recommend against daisy-chaining all the positive ground pedals to a dedicated one spot? I thought yours worked great? Is it just that it has a big potential risk associated with it?

Thanks!
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Re: Stupid Power Question (Positive Ground)

Postby Barcode » 07 Oct 2011, 22:20

joinpobob wrote:Thanks for the info!

I have a few LT1054 (I think). I will give them a try.

Why do you recommend against daisy-chaining all the positive ground pedals to a dedicated one spot? I thought yours worked great? Is it just that it has a big potential risk associated with it?

Thanks!


not so much that. It's the idea of maintaining two separate supplies, for the reasons you just mentioned (potential to accidentally hook a pedal up on the wrong one). It's not a big risk, just personal preference. I didn't use a dedicated onespot for the positive grounds, I built a breakout box that converted power to positive ground through 4 separate 1044 circuits that went to 4 jacks on the front of the breakout box. I ran positive ground pedals from there, and daisy chained the rest off the main line. Making a breakout power conversion box like i did eliminates the need for another power supply.
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