Circuit works without power but not with power

[wenzelli]

I built a basic range master circuit on breadboard  from the original schematic which works when plugged into my amp but when I put the battery in the battery clip the guitar signal won't make it to the amp. Anybody got ideas? I figure it's a simple fix but this is my first pedal build. Could post pictures later if needed

[Phoenix]

Welcome.

Congrats on accidentally discovering free energy!

Better hide it before "they" come to destroy the evidence...

[willienillie]

I can see how signal could get through an unpowered rangemaster, but it should be significantly weakened, not boosted.

Did you use a PNP transistor?  Do you have your power polarity correct?

Could post pictures later if needed

Yes, please.

Better hide it before "they" come to destroy the evidence...

Shhh!!!

[wenzelli]

I can see how signal could get through an unpowered rangemaster, but it should be significantly weakened, not boosted.

Did you use a PNP transistor?  Do you have your power polarity correct?

My wording is probably wrong. The signal gets through and I can definitely hear clipping from the transistor but I don't think the level is being boosted at all although it is just about the same as when running straight into the amp. I did use a PNP and I assume power polarity is correct, the circuit is positive ground so I plugged the red wire into the negative rail and black into positive.

[willienillie]

the circuit is positive ground so I plugged the red wire into the negative rail and black into positive.

Yes, but if you're going to use the "negative rail" as ground, you need to connect ALL ground connections to it.  You have your jack sleeves and 68k connected to the other rail, maybe others I can't see.

What kind of transistor is that?  I'm not getting much searching 9270.

edit:  It might be the case that you just need to flip your battery wires, and it will fire up.  Saying that without seeing the whole picture, and not knowing anything about the transistor.  But mostly anyway, you've wired it so in such a way that you didn't need to reverse your battery leads.  Hopefully the electrolytic cap hasn't been damaged (wrong value anyway).

[wenzelli]

the circuit is positive ground so I plugged the red wire into the negative rail and black into positive.

Yes, but if you're going to use the "negative rail" as ground, you need to connect ALL ground connections to it.  You have your jack sleeves and 68k connected to the other rail, maybe others I can't see.

What kind of transistor is that?  I'm not getting much searching 9270.

edit:  It might be the case that you just need to flip your battery wires, and it will fire up.  Saying that without seeing the whole picture, and not knowing anything about the transistor.  But mostly anyway, you've wired it so in such a way that you didn't need to reverse your battery leads.  Hopefully the electrolytic cap hasn't been damaged (wrong value anyway).

I'm not sure which transistor it is. on small bear it is labeled as PNP US. I have tried to flip the wires to no avail. I'll try swapping the cap out for a 47 and see if that works. Thank you for the replies! If you want any other info let me know

[Phoenix]

Ok, more seriously, there's a few things that require clarifications.

Have you added a bypass, or built it stock, no bypass?

If you did add a bypass, under which conditions does it pass signal? Unpowered bypassed? Unpowered engaged? Powered bypassed? Powered engaged?

Have you tried the debugging guide yet?

You say you connected a red wire to the negative rail, and a black wire to the positive rail. Was that a battery snap?
If so, I'm afraid you got it backwards. Red will ALWAYS go to the positive rail (since it is positive), and black will ALWAYS go to the negative rail (since it is negative). Only exception to this is if you have two batteries for bipolar power rails in which case one battery will connect red and the other black to ground - 0V. The confusion here is that the positive rail is ground, and we've been conditioned into thinking of ground as "negative", when it's not at all - it's just a reference point, it can be any polarity or magnitude we want. If we call the negative terminal of a battery ground, then the other terminal will be positive relative to ground, and this is what we're accustomed to seeing. But we can equally call the positive terminal ground, and the the other terminal will be negative with relation to ground.

But, unfortunately, if you did hook up a battery or power supply as described, and you didn't add a protection diode to your build, then you have destroyed your transistor. If you have a multimeter with diode function you can test it, but it is very likely to be short circuit now.

[wenzelli]

no bypass. The circuit passes signal to amp only when there is no battery. What I used was a battery snap.

If so, I'm afraid you got it backwards. Red will ALWAYS go to the positive rail (since it is positive), and black will ALWAYS go to the negative rail (since it is negative).

Thanks for clearing that up for me.
The confusion here is that the positive rail is ground, and we've been conditioned into thinking of ground as "negative", when it's not at all - it's just a reference point, it can be any polarity or magnitude we want. If we call the negative terminal of a battery ground, then the other terminal will be positive relative to ground, and this is what we're accustomed to seeing. But we can equally call the positive terminal ground, and the the other terminal will be negative with relation to ground.

And this.

But, unfortunately, if you did hook up a battery or power supply as described, and you didn't add a protection diode to your build, then you have destroyed your transistor. If you have a multimeter with diode function you can test it

It is strange that I can hear clipping from the transistor added to the signal when running without a battery. I don't think I broke it since it is very pleasant sounding but maybe I am wrong. I'll look into testing transistors I don't know how to do it yet. If you know of one please link a resource for testing them and for adding a protection diode

[Kipper4]

This happened to me a few times.
Usually its because i have the connections reversed, meaning i plugged the guitar into the output and the amp to the input of the pedal. Doh
Worth checking.....................

[GibsonGM]

To test a transistor, you place your DMM on the 'diode' setting.   For a PNP, you'd put the black probe on the base, and measure from base to emitter, then base to collector.    You should see a diode-level voltage drop displayed on your DMM, such as " .517", showing that the internal 'diode' is functioning. 

For an NPN, you reverse the probes.  If you use the opposite polarity and try to test (say, red probe on PNP base), you should get no response.   

https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07


A bit on protection diodes and other circuits.

http://www.geofex.com/article_folders/cheapgoodprot.htm