Rangemaster build - fuzzy and octaver type of sound

[bancika]

Yesterday I built a dallas rangemaster that I intend to use together with a small Ge amp I salvaged from an old radio (similar to Deacy). The amp is relatively clean on it's own and a tad warm sounding, so I wanted to push it slightly harder and shape the sound. I don't have the recommended OC44, but with all transistors I tried (tried AC125, AC151, AC153, ACY51, GT308V, MP39B, all with gains between 20 and 110), the sound is very fuzzy and has octave/ring type of "quality"...I expected it to push the sound less dramatically that that

I checked the wiring and resistor values and so far everything checks out. Obviously, I have to do more debugging, but I wanted to ask - is it possible for the circuit to work with a wrong pinout? I tried around 10 transistors, but it's possible that I messed up pinout every time I was wondering if it would be possible to get this kind of sound?

I'll try splitting the amp from the booster and testing them individually to see where the fuzz comes from. I suspect it's the rangemaster, as I've tried the amp with an overdrive pedal before and it was fine.

Cheers

[Elijah-Baley]

Check the pinouts with a schematic and the datasheets of the transistors.

Maybe you could consider to build another booster. I never tried the Rangemaster, but I built a Brian May Treble Booster and seems to me "cleaner" than the Rangemaster.

[bancika]

thanks for the reply. I went with the rangemaster because it's PNP and most germanium transistors I have are PNP. Also, it will be packed in the same box with the amp which is PNP, so it's convenient to power them with the same source. Looking at the schematic, it shouldn't be *that* different. I wouldn't expect any single transistor booster to fuzz

[anotherjim]

I would think if you managed to measure believable Hfe, then you had the pin-out right. You can get audio bleed thru a circuit with the polarity (power or Tr) wrong, but my first suspicion is to look for a bias issue - it the extra input stage AC coupled to the amp? Is the coupling cap good?

[bancika]

thanks!

I measured gain and leakage around 3 years ago, labeled everything and had them stashed away until now. There's a 10nF capacitor at the end of the rangemaster, but there's also a 10nF capacitor at the input of the amplifier (they effectively halve the total capacitance), but there shouldn't be any DC coupling. I'll measure DC just in case.

I measured bias around -7V with most transistors, but now that I think of it, I got that value on the pin that is supposed to be base, not collector. The other two pins were around -1V

[bancika]

yeah, probably bad pinout. I looked at it again with fresh eyes and tried few transistors, it sounds much better. I'll post a build report once it's all done, amp and booster.
Cheers

[Caferacernoc]

Adjusting the bias closer to like 5 volts from 7 will also clean up and fatten the sound.