PNP Ge Rangemaster debugging :)

[Arangonix]

Hi guys,

need some advise with my recently built Randemaster clone. The pedal works fine in terms of sound and I must admit it sounds darn good with my tweed
I decided to add a DC jack as a addition to the standard 9V battery clip - two options better than one i thought: D
I still didn't test the DC jack, but I noticed that the battery can get petty warm just after few minutes of using it. Probably it shorts somewhere, but dunno where.
I wired it like that: black battery wire to DC jack pin (and I also have a wire to board from here), red one to connect and I used a DC jack sleeve as a battery on/off, connecting it to the input jack sleeve .
Input jack works properly, when the guitar is connected the effect works, when I unplug the input jack, it turns off. But the battery heating is worying me.

Did I messed up the battery/DC jack wiring?
I've used a "barrel" style DC jack, like this one:

https://www.pcboard.ca/dc-power-connector-2-1mm-metal-plastic-panel-mount.html

[willienillie]

I don't know how you've wired it, but you probably want a plastic-body DC jack to avoid shorting your battery out.

[Arangonix]

Ok, so how to do that, I mean what should I solder and where?

[Arangonix]

The electrosmash.com states about Rangemaster:

"PNP Positive Ground: it is the original circuit. It sounds fantastic but the problem with it is that if you want to use an external DC adapter (and not only batteries) it will create a short circuit (see how the input and output jacks are referenced to +9V and not ground). The original box never faced this issue because it only works on batteries. So please do not use a daisy chain power adaptor with a positive ground guitar pedal."

Kind of weird as tere are PNP Rangemaster's clones which have both DC jack and 9V battery clip. Any ideas?

[Govmnt_Lacky]

Kind of weird as tere are PNP Rangemaster's clones which have both DC jack and 9V battery clip. Any ideas?

Lately, people have designed PNP circuits with charge pumps in order to maintain the "positive ground" needed for the PNP transistors BUT... they can power them with a normal DC jack and battery.

Take a look at this from GGG:

http://www.generalguitargadgets.com/pdf/ggg_geb_cp_instruct.pdf

IT explains how they modded their Dallas Arbiter PNP circuit with a charge pump circuit so it can be powered like any other.

[Arangonix]

Still, there are Rangemasters without pumps working on batteries + DC jack. Not a charge pumps fan here
I did many FF style pedals using DC jack + battery clip wiring which worked properly. Thought this Rangemaster circuits won't be an exception.

[idy]

Those modern RM and FF clones w/o charge pumps are often made with NPN transistors so they can daisy chain.

[Arangonix]

Rangemaster with 9V battery clip and DC jack. No pump here.

[Marcos - Munky]

Since we don't know which transistor were used on this one, it could be a NPN one. So easy to add a dc jack without using a voltage inverter.

Btw, battery getting hot indicates you're shorting the battery pins. That happens because you're using a metallic jack. Guitar effects have the "negative" voltage on the center pin of the jack and on the enclosure, since both "negative" voltage and the enclosure are connected to ground. So, the "positive" voltage is in the outer lug of the jack. Since you jack is mettalic, the outer lug (positive) is touching the metallic part of the jack, with is touching the enclosure, which is connected to negative. So you're shorting your battery, and good chances it is dead (remember a battery don't need to go to 0V to be considered dead. a battery with around 8V is already dead for lots of stuff).

[Arangonix]

Hey Munky, OC71 was used here.
I also thouht it may shorts because of enclosure so I've unscrewed DC jack and isolated it with insulating tape. I made sure it won't touch any metal parts. Battery became warm once again.

I don't understand exactly why input and output jacks are referenced to +9V and not ground, as I can read on electrosmash.com. This is the first time I see sucha thing. I'm not super experieneced but I'm building different clones with mods for some time now nad never had circuit working like that.

[bluebunny]

I don't understand exactly why input and output jacks are referenced to +9V and not ground, as I can read on electrosmash.com.

The +9V rail is ground.  This is why it's called "positive ground".  The place you choose to call "ground" (or "0V") is entirely arbitrary.  Consider this: your 9V battery gives you two power rails.  One is 9V more positive than the other.  Or: one is 9V more negative than the other.  Either way you look at it, which rail you choose to call "ground" is up to you (and your circuit).  You might help yourself by labelling the battery not with "+9V" and "0V", but with "0V" and "-9V".

This is really only a conceptual problem for us folks who mess with guitar pedals powered by a single 9V battery.  Everywhere else in audio-land you have bipolar power supplies, for example +12V and -12V.  "Ground" is conveniently assigned to the mid-point between these rail which are 24V apart (more "conveniently" than you might imagine...).

[Arangonix]

I get it, but, let's say, the oldest Ge FF is also a "positive ground" circuit. In this case, I should have the same problem with it's clone. Still, wireing it exactly like the Rangemaster I've made, the FF works totally good. It has "real" ground (0V). What I'm trying to do here is to get those 0V in Rangemaster's ground rail instead of +9V.