Rangemaster part values?

[jkokura]

Hey guys,

I'm building a Rangemaster clone using Madbean's layout: http://www.madbeanpedals.com/projects/Rangemaster/RangeMaster_ver1.pdf

The 7003 I got from Smallbear came with two resistors and a note about how it was tested with these values. I wanted to build it with some mojo parts and got the recommended Rangemaster Germ Transistor from Smallbear, and some Ohmite Carbon Comps and Axial Film and Electrolytic Caps.

I should have looked harder for the right values, or waited until my transistor was here I guess, cause I have a few parts that aren't quite right. The note from smallbear says to use 51k and 3.6k resistors, but I have 68k and 3.9k like the project suggests. As for caps, I have a 4.7n instead of a 5n (I thought this would be fine), and I have some 50uF instead of 47uF (again I imagine this is fine) but I just want to double check that my pedal will turn out right. I don't want to solder these in and find that it doesn't sound good, so let me know what you guys think/know about rangemaster part values.

Jacob

[Brymus]

The caps will be fine.
Using carbon comps at less than 300 volts wont add any mojo,just extra noise.
RG has a good read about that at his site.
I would check the resistors by trying them on your breadboard the 68K might be too far from 51K to get the bias where it needs to be.
The smaller resistor should work.
Again the breadboard is your friend here.

I have a Rangemaster on my breadboard right now,using a Russian Ge tranny.
So I have experimented with pots for the resistors,and using the Ge diode to stabilize the bias.
You should try that too if the pedal will be used live.
Look at the Rangeblaster schematic at fuzz central,I would post it but rules are rules.

[R.G.]

The note from smallbear says to use 51k and 3.6k resistors, but I have 68k and 3.9k like the project suggests. As for caps, I have a 4.7n instead of a 5n (I thought this would be fine), and I have some 50uF instead of 47uF (again I imagine this is fine) but I just want to double check that my pedal will turn out right.

The parallel combination of resistors R1 and R2 is Rparallel = R1*R2/(R1+R2) . For an A in algebra, if Rparallel is 51K and R1 is 68K, what is R2?
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Yes, correct! R2 = Rparallel*R1 / (R1-Rp)

So if you have R1 = 68K and you want Rparallel to be 51K, then R2 (that is, what you parallel with the 68K) is R2 = (51K*68K)/(68K-51K) = 204K. So you can parallel the 68K you have with 204K (or two 100K in series) and have a 51K.

The cap substitutions are fine.

[bean]

Or, I can send you a 51k....but it's carbon film

But, yeah...R.G. is right on...memorize (or use Excel) those formulas. I use them all the time.

Actually, I have a spreadsheet with 3 or 4 formulas loaded in. Let's see, parallel resistance, freq. roll-ff, maybe something else. I'd be happy to share.

[jkokura]

I have Carbon Film and Metal Film for the values, I was hoping for Carbon Comps on this one, hence the ordering of the 68 and 3.9k Carbon Comps. Perhaps the best option is to find someone who has 68k and 3.9k carbon comps and trade some other parts for them.

Jacob