Dallas Rangemaster: voltage collector

[ricci]

With the 33nF cap between E and C I reduce the frying noise that is in the background

Strange way for inreasing Power Supply Rejection Rate ..

I don't know why this happens but it greatly reduces the background air blow noise by slightly modifying the tone of the guitar but which always remains bright.

[percyhornickel]

that tranny is silicon
of course it has less noise.

i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!

cheers, Iain

I really would like to hear the RM with this transistor, don´t you have any sound on the web or some site?. I just saw the BD139 hfe = 40, perfect for a RM.

[willienillie]

hfe = 40, perfect for a RM.

Maybe with a 25K pot.

[ricci]

hfe = 40, perfect for a RM.

Maybe with a 25K pot.

Is there a formula to determine which potentiometer to install according to the hfe?

[iainpunk]

that tranny is silicon
of course it has less noise.

i had my BD139 range master biased at 8.4V since it sounded the best there, it gave me a punk-rock sound when used in a clean amp and a really tight hard hitting grind when used into a dirty amp, but i biased it really close to gating, just at the brink. so its no problem to bias it anywhere else, just use your ears to where it sounds best!

cheers, Iain

I really would like to hear the RM with this transistor, don´t you have any sound on the web or some site?. I just saw the BD139 hfe = 40, perfect for a RM.

i'm sorry but i don't have that pedal anymore (the transistor is now part of my DIY class A amp), and i don't have sound recordings either. but it wasn't too different from most range masters, just a bit more broken when into a clean amp but in to a driven amp the difference is really small. i recommend replacing the 68k resistor with a 100k or 220k trim pot so you can change the bias to your liking. i believe i used a 47pF capacitor between the collector and base to simulate a germanium's miller capacitance, but that only makes a small difference.
a range master with such a trim pot, and the miller capacitor and transistor in sockets is easy to experiment with, you can just pull out the cap or transistor and change them for other values/types. and the bias trim pot makes it able to accept most transistors with low-ish gain. i strongly recommend making a flexible board with sockets, so you can mix, match and experiment your own perfect sound!

cheers, Iain

[iainpunk]

hfe = 40, perfect for a RM.

Maybe with a 25K pot.

why would that be necessary? especially with a bias trimmer, i don't see the need for a 25k pot, unless you really need that extra gain. the original oc44 transisor is about the same gain and really low leakage (for a germanium). the reason a BD139 is great is the low gain (comparable in range) and relatively high leakage (for a silicon).

cheers, Iain

[ricci]

After I solve one problem, another one occurs. Could you tell me why, with the RM activated, when I set the guitar pot to zero, I hear a noise similar to that of the air coming out of the tire when I press the valve ?

https://voca.ro/1cnflRU94gh5

[willienillie]

hfe = 40, perfect for a RM.

Maybe with a 25K pot.

why would that be necessary?

I don't know, I got the idea from RG's Austin Treble Blaster paper.

http://www.geofex.com/article_folders/rangemaster/atboost.pdf

Basically, a higher collector resistor.  It worked for me to get a 40ish transistor to bias up well, which wouldn't with a 10k pot.  Maybe the base-to-ground trimmer gets there too, but maybe at a fairly extreme setting.  But either way, I have had better results with hFE around 70, and a 10k pot.

[Big Monk]

Personally, I feel the Rangemaster has to be built with a Germanium transistor. Full stop. I've built plenty of Silicon ones myself and the mojo is in a properly tuned Germanium unit.

[iainpunk]

Personally, I feel the Rangemaster has to be built with a Germanium transistor. Full stop. I've built plenty of Silicon ones myself and the mojo is in a properly tuned Germanium unit.

i think it depends on what you want, if you like a riff-raff punk sound, a Si does the job well,
if you like smooth rock/pop sounds, definitely use Ge.
i think the black sabbath sound is to be discounted since Toni's range master was heavily modded, allegedly using a ''really large'' input cap, nicer resistors and another tranny.

cheers, Iain

[ricci]

I read on the web that the last noise I described has it in many users and some say that the cause is germanium but it also happens to me with silicon and with any guitar. Some experts at least to understand if I have to live with it ?

[Big Monk]

I read on the web that the last noise I described has it in many users and some say that the cause is germanium but it also happens to me with silicon and with any guitar. Some experts at least to understand if I have to live with it ?

can you describe be again the issues you are having?

[ricci]

can you describe be again the issues you are having?

I am referring to the volume pot of the guitar. As the volume decreases, when I get to position around 3, I start to hear a white noise that gradually increases as I reduce to position 2 and then to 1 to zero. Here the white noise reaches its maximum intensity

[Big Monk]

can you describe be again the issues you are having?

I am referring to the volume pot of the guitar. As the volume decreases, when I get to position around 3, I start to hear a white noise that gradually increases as I reduce to position 2 and then to 1 to zero. Here the white noise reaches its maximum intensity

Is this the same hiss you were initially assigning to the transistors in the boost circuit?

[ricci]

no, the hiss I said initially is the background white noise that is always present while this white noise, that is accentuated with the closing of the guitar volume potentiometer, I have discovered it only now. Given how the potentiometer works, in my opinion the ground is involved but I don't know  what to do, maybe some electrolytic capacitor placed in some strategic point but I can't be sure and I wouldn't want to do other random tests. Does the same thing happen to you ?

[Big Monk]

no, the hiss I said initially is the background white noise that is always present while this white noise, that is accentuated with the closing of the guitar volume potentiometer, I have discovered it only now. Given how the potentiometer works, in my opinion the ground is involved but I don't know  what to do, maybe some electrolytic capacitor placed in some strategic point but I can't be sure and I wouldn't want to do other random tests. Does the same thing happen to you ?

How confident are you that your guitar wiring and the controls within it are wired correctly?

[ricci]

How confident are you that your guitar wiring and the controls within it are wired correctly?

to 1000/100

[ricci]

As already mentioned, the problem happens with all my guitars but I begin to think that it is precisely the transistor so much so that in the drawer I found a BD137 that does not produce white noise in the background though at the output I always have the noise in the closing of the volume pot.

[ricci]

Finally, I found that the white noise and hum were caused partly by the power supply but mostly because there is also a digital pedal with which it shared mass. When I used two separate power supplies, the noise disappeared. I also tried an AC142K transistor with HFE equal to 138, which turned out to be quite noisy, and in the end I preferred the AC127 because the PNP was really noisy.

[zbt]

last time I tried, made a 470K resistor as a trimmer and feedback, by connecting it to the collector, like a bigmuff circuit which is not very sensitive to hfe.