Dallas Rangemaster NPN

Jiberjew

Jiberjew

Member
Hope everyone is good!! I'm trying to build a NPN version of the Dallas Rangemaster. I actually got some PCB's made based off of electrosmash's schematics (https://www.electrosmash.com/images...emaster-positive-negative-ground-circuits.png). I followed it to a tee. Soldered it up, no luck. Troubleshot it, all looks good. As I am still fairly new to this, the only issue I see is the switch wiring. I took a page out of PedalPCB's book for that. I can post the schematics I drew, if anyone would like to see that. I'm nearly positive I have a 3PDT switch wiring issue. I am following basic pedal switch wiring, if that helps. Also using BC108 transistors, if that helps. Anyhow, thats in advance for any feedback!
 
Jiberjew said:
Hope everyone is good!! I'm trying to build a NPN version of the Dallas Rangemaster. I actually got some PCB's made based off of electrosmash's schematics (https://www.electrosmash.com/images...emaster-positive-negative-ground-circuits.png). I followed it to a tee. Soldered it up, no luck. Troubleshot it, all looks good. As I am still fairly new to this, the only issue I see is the switch wiring. I took a page out of PedalPCB's book for that. I can post the schematics I drew, if anyone would like to see that. I'm nearly positive I have a 3PDT switch wiring issue. I am following basic pedal switch wiring, if that helps. Also using BC108 transistors, if that helps. Anyhow, thats in advance for any feedback!
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please post well-focused detailed pics of your build so that it can be assessed :)

(the troubleshooting sub-forum is the place for this type of thread)

Troubleshooting

forum.pedalpcb.com forum.pedalpcb.com
 
owlexifry said:
please post well-focused detailed pics of your build so that it can be assessed :)

(the troubleshooting sub-forum is the place for this type of thread)

Troubleshooting

forum.pedalpcb.com forum.pedalpcb.com
Click to expand...
Ohhh shot!! You're right, wrong sub-forum, thanks! It's been a frustrating day! I tried to move it to that sub forum, but I think is too late. I'll post a picture of the 3PDT switch tomorrow, my sons been chomping at the bit to jam with me, but I attached a pic of my schematic. The 3PDT wiring is the same as pedalPCB's. I posted a picture of that for reference as well, my PCB has the in/gnd/sw/out just as the pedalPCB pic I posted, and the 3PDT is wired the same as the pic. Hopefully this helps. I can post the actual build, if needed, tomorrow. Thanks again!
 

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Nostradoomus said:
difd you test + measure your transistor?
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I will tomorrow. Electrosmash suggest I have +2 volts to ground across the collector, +8 volts to ground across the base and +8.2 volts to ground across the emitter. I hope this sounds right. I've never biased my transistors before, so I'd have to research that a bit. I did run across a similar issue like this before, so you might be onto something.
 
Jiberjew said:
I will tomorrow. Electrosmash suggest I have +2 volts to ground across the collector, +8 volts to ground across the base and +8.2 volts to ground across the emitter. I hope this sounds right. I've never biased my transistors before, so I'd have to research that a bit. I did run across a similar issue like this before, so you might be onto something.
Click to expand...

It's really the only mildly complicated part of a rather simple circuit so it would add up :ROFLMAO:
 
Nostradoomus said:
It's really the only mildly complicated part of a rather simple circuit so it would add up :ROFLMAO:
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The other pedal I was working on was that had a similar issue was a zonk machine style fuzz. I was using PNP transistors and could never get it to work. Gave up, moved on and put it in the "to do later" pile. hahahaha. If I can figure out how to bias the transistors, I can probably get that zonk machine going. After my jam session with the boy, I'll look into how to do that. Audio circuits are still new to me, I got about 6 months under my belt. 4 builds I designed and quite a few from here. It's a lot of fun for sure, but I'm an electrical engineer for the power distribution industry and audio circuits are no where close to that, hahahaha! So I have a mild learning curve for sure!!
 
Jiberjew said:
The other pedal I was working on was that had a similar issue was a zonk machine style fuzz. I was using PNP transistors and could never get it to work. Gave up, moved on and put it in the "to do later" pile. hahahaha. If I can figure out how to bias the transistors, I can probably get that zonk machine going. After my jam session with the boy, I'll look into how to do that. Audio circuits are still new to me, I got about 6 months under my belt. 4 builds I designed and quite a few from here. It's a lot of fun for sure, but I'm an electrical engineer for the power distribution industry and audio circuits are no where close to that, hahahaha! So I have a mild learning curve for sure!!
Click to expand...

sounds like it adds up to what we're talking about. ge trannies are a fickle mistress lol
 
Nostradoomus said:
sounds like it adds up to what we're talking about. ge trannies are a fickle mistress lol
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Sounds like you are correct. I have 8.43vdc across the collector and ground. 9.14vdc across the base and ground and 8.42vdc across the emitter and ground. So, now I need to figure out how to correct that.
 
Well, thanks for all the help, I got the rangemaster up and running. AND I learned how to bias transistors haha. Which is going to help tremendously! I used a few different transistors, but went back to the gritty BC108. I put it in line with a tube screamer style pedal I designed and WOW! Defiantly not the tone I was looking for, but I found something better! I guess when I get sick of throwing that rangemaster in with a fuzz or overdrive, I’ll get back to the tone I’m really looking for (which I think I already found and off to building an amp now). Thanks a bunch! Everyone here is a huge help!
 
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