Rangemaster - Modern germanium transitor equivalents?

[tubeswell]

I love the sound of Clapton's 'Hideaway' guitar, and seeing as how I have a 'JTM45 equivalent' in the cupboard, I decided I'm GASin' for the promise of sounds I could get with the Rangemaster.

I see from RG's article, that the OC44 equivalents could be NKT275, 2N527, 2N508, 2N404, 2SB75, and that ECG158 works well 'if you can get the right one'. So in today's market (for one like myself who doesn't understand much about SS), what is the 'right one', and/or what off-the shelf equivalents should I keep an eye out for. TIA

[kleuck]

Hello.
First, i must say that i do not thing that EC ever used a TB, i cannot hear one in any of his tracks (it's not always obvious though)
I am building modern treble boosters -with NO germanium transistor- and recently i tried to build a modernized Rangemaster, still a work in progress but i already sold a few ones.
Just to expose who i am.
I don't expect to sell a lot of my pedals to US considering the euro/dollar ratio and the shipping costs, so I'm not in a marketing, hum "path" ? (sorry i'm french) but actually i had to compare my work on the "modernized germanium booster" to a good RM son or grand son, and used an Analogman Beano as a reference (because one of my first customer had one and was willing to be my first tester, not too far away from me so we can meet etc, casual stuff....) so i can say : if you want a good (indeed great) germanium treble booster, buy a Beano.
Sound is awesome, construction is realy good, the man added a lot of dc filtering, a really really good pedal.

[kleuck]

I'm not sure to have understood the question so, if the point is "how to build a good one by myself ?" i will say that the exact transistor reference is not so important, as long as you can get a good one (not too leaky and at least 40 of hfe) and make your circuit tunable ie : you can adjust the idle current to your taste.

[dai h.]

if you happen to find some and they are old Japanese ones, I would be careful not to overlook them. They can be quite good IMO. There was a guy on another forum (who was in NZ) who found a huge stash of 2SB172(?) and I advised him to just buy the whole lot (if cheap enough or cheap) and he ended up selling selected pairs (for Fuzz Face use) to DIYers (for a reasonable fee) and kept some for himself.

re: the supposed Clapton connection, I also am not quite convinced and think this could be more of an internet myth. Having said that though, the thing is just so simple I think you should build one for the heck of it and have fun with it regardless of whether he used it or not. I'd also suggest trying cheap ceramics for one or both of the small caps (that's what some units had--to be specific, old style red "dogbone" shape ones). Might give a bit more "colour" and make it a bit more interesting (or maybe go the other direction using something like a polystyrene or polypropylene for a "purer" less coloured tone).

[tubeswell]

Okay so if I can't find germanium transistors here (in NZ), what sort of PNP transistor would I put in place of the OC44 in that booster circuit? (I can't find any of the other transistors that R.G. had in his article either). I understand very little about transistors and their classisfications. (R.G.'s article is attached BTW)

[kleuck]

A germanium is mandatory in this circuit, and it must have at least a gain (hfe) of 40.
I use OC75, AC128, SFT323 and less known japanese transistors (2SAxxx).
You can also build a modern Treble Booster like the Omega : Omega

[dai h.]

I would try whatever you can get ahold of cheaply or reasonably. I would guess the maker just used cheap gen. purpose ones (though way back then, transistors might not have been super cheap as you can find today). IIRC some came with OC71, so (I'm guessing here, but) maybe OC44 was due to availability or perhaps they were lower noise. re: the gains, FWIW in my limited experience (measuring a couple hundred I had gathered over a few years here and there) finding a Ge with a gain of around 40 should be far easier than getting one for the (2nd?) one in a Fuzz Face (120 or so with low enough leakage) as far as (the apparent) relative ease of sourcing an appropriate transistor (meaning that I personally found many more in the lower gain range than the higher).

[Steve Conner]

Why is a germanium mandatory? Treble boosting is treble boosting, you can do it with tubes, op-amps, whatever. A silicon transistor may not sound right in the Rangemaster circuit, but you don't have to use the Rangemaster circuit.

I'd be tempted to try the MPSA92, it's a high voltage silicon transistor, and being high voltage it has low gain. Or MPSA42 if you want a NPN booster that runs off the same supply as your other pedals.

I got a batch of germanium transistors from a friend, intending to make a Fuzz Face, but they were mostly too leaky to be usable. There was an OC44 in there, but it had too much gain and was noisy. Nevertheless the best FF tone I got was with that in the first position and the least leaky AC128 in the second. I probably should try the OC44 in a Rangemaster circuit.

[dai h.]

(Electro-Harmonix) Screaming Tree is a silicon transistor one (treble booster). Then there's that one Brian May supposedly used (also Si transistor) the schematic of which should be floating around on the interwebs somewhere. I suppose you could use an EQ as well. Oh, and the way Ed Van Halen used the Phase 90 is treble booster-ish as well.

[kleuck]

Why is a germanium mandatory? Treble boosting is treble boosting, you can do it with tubes, op-amps, whatever. A silicon transistor may not sound right in the Rangemaster circuit, but you don't have to use the Rangemaster circuit.

Because, no, a treble booster with a germanium transistor is NOT a treble boosting device, but a mids & hi-mids booster.
If you try a silicon one in the RM circuit, apart from the biasing wich would not be right, you'll end with an ear-piercing device.
That's why the Brian May circuit for example has a low pass filtering, cutting the highests frequencies, where a RM doesn't need cause it has a poor response in highs actually.
Apart from that, a RM is producing hi levels of even order harmonics and has great sounding and chewy distortion on his own, where a Si one....

[Steve Conner]

So you're saying that the germanium transistor itself has such a bad frequency response that it limits the treble boost? I've heard that they have a very low ft, but didn't realise it was as low as that.

Any cheap silicon transistor will amplify to several MHz, so that would be a problem. Maybe you could whack a large capacitor from collector to base, to slug it.

If a Rangemaster doesn't actually boost treble, maybe that explains why it isn't so obvious on the Beano album. I heard that Clapton turned the tone knob on his guitar down and used the neck pickup, then used the treble boost to put some of the highs back. That's why the Beano tone sounds so fat and creamy, but still has some detail in it.

[kleuck]

Not only the transistor by itself actually, but also the low impedance of a germanium treble booster.
The low gain of the transistor implies a low base impedance, wich comes in // with the bias bridge, so the real input impedance of a RM is ver very low (around 12 Kohms) and cuts out all the higs just like a 50 ft long crappy cable.
In my modern TB i had to put an lowpass filtering too, and it's the same ith the Omega.

If a Rangemaster doesn't actually boost treble, maybe that explains why it isn't so obvious on the Beano album. I heard that Clapton turned the tone knob on his guitar down and used the neck pickup, then used the treble boost to put some of the highs back. That's why the Beano tone sounds so fat and creamy, but still has some detail in it.

Yes but usually you can her the "grit" of the transistor, wich is very very unique, remaining the dirt you can get from a pentode.
Anyway, a TB wathever technology it's build from, is a really usefull cirucit with tubes amps, and indeed, the Beano (wich is mostly a RM clone) is fat fat fat (i try to nail this fatness with my own modernized Ge TB, but it's really not easy.
Here a sample trough a Badger 30, the guitar is an ash Telecaster, first the amp only, then the Beano, then my own pedal : btb_1.mp3 - File Shared from Box.net - Free Online File Storage

[J M Fahey]

Why is a germanium mandatory? Treble boosting is treble boosting, you can do it with tubes, op-amps, whatever. A silicon transistor may not sound right in the Rangemaster circuit, but you don't have to use the Rangemaster circuit.

I'd be tempted to try the MPSA92, it's a high voltage silicon transistor, and being high voltage it has low gain. Or MPSA42 if you want a NPN booster that runs off the same supply as your other pedals.

At last the (or "a") voice of Reason.
I didn't want to get into Faith based discussions, but now that I see I'm not alone, let me state that we do not only not need Germanium, we do not need it to be PNP; even more, we do not even need it to be a Transistor.
For me, *parts* are not important; *what it does* is.
It can be reasonably cloned using that wonderful building block: the Op Amp.
What does it *do*, in essence?:
1) Amplify? ... check
2) have a low and reactive input impedance, such as .005uF in series with 12K ? ... check
3) Have unity gain at 80 Hz? ... check
4) Have a 6dB/octave rising response? ... check.
5) Have a 6dB octave rolloff from 5KHz up, so the gain is not 60x but 30x (because of 6dB loss at that frequency?) ... check.
6) Have the same (constant) gain (around 30X) from that frequency up, because input rising 6dB/oct gets compensated by 6dB/oct rolloff, leaving net change around 0dB? ... check.
7) There are claims of second harmonics and nonlinearities .
Can't calculate them out of the top of my head as in points 1 to 6, but the practical approach would be to build an original clone, germanium transistor and all, hit it with various frequencies at different levels, and duplicate that adding an approppriate non-linear network in the feedback loop, one specialty of Op Amps.
8) Noise/unavailability/lack of repeatability/unbearable crackle/major Pop ? ... we can leave them out of the equation, can't we?.
9) Let's not forget that the Rangemaster does not sound by itself (nobody sends it right to the recording console) but is an equalizer and pre-processor for a classic overdriven tube amp, which does 95% of the work.
10) Where's the Mojo? ... good question.

[dai h.]

but you won't be able to charge as much for it since, "it's not exactly what Clapton used"(supposedly). Getting the same result using a different way is outside the realm of mojo thinking. (and beyond my skill level also, lol)

[kleuck]

At last the (or "a") voice of Reason.
I didn't want to get into Faith based discussions, but now that I see I'm not alone, let me state that we do not only not need Germanium, we do not need it to be PNP; even more, we do not even need it to be a Transistor.
For me, *parts* are not important; *what it does* is.
It can be reasonably cloned using that wonderful building block: the Op Amp.
What does it *do*, in essence?:
1) Amplify? ... check
2) have a low and reactive input impedance, such as .005uF in series with 12K ? ... check
3) Have unity gain at 80 Hz? ... check
4) Have a 6dB/octave rising response? ... check.
5) Have a 6dB octave rolloff from 5KHz up, so the gain is not 60x but 30x (because of 6dB loss at that frequency?) ... check.
6) Have the same (constant) gain (around 30X) from that frequency up, because input rising 6dB/oct gets compensated by 6dB/oct rolloff, leaving net change around 0dB? ... check.
7) There are claims of second harmonics and nonlinearities .
Can't calculate them out of the top of my head as in points 1 to 6, but the practical approach would be to build an original clone, germanium transistor and all, hit it with various frequencies at different levels, and duplicate that adding an approppriate non-linear network in the feedback loop, one specialty of Op Amps.
8) Noise/unavailability/lack of repeatability/unbearable crackle/major Pop ? ... we can leave them out of the equation, can't we?.
9) Let's not forget that the Rangemaster does not sound by itself (nobody sends it right to the recording console) but is an equalizer and pre-processor for a classic overdriven tube amp, which does 95% of the work.
10) Where's the Mojo? ... good question.

Many people tried, as far as i know, nobody suceeded.
With my Ballast (non ge modern version), i nail the RM sound, but it's not exactly the same grit.
YouTube - Ballast "Trouble Booster" demo 2 - Treble Booster pedal by Le Gecko Electrique
Even with tubes it's not easy to emulate the EF86 sound.
Yes, of course a TB is meant to be used in front of a Tube amp, just as a guitar is meant to be plugged in a guitar amp, not an HiFi one, what's the point ?
A good clone of RM does not crackle or pop...but it can be a good radio tuner, and can hiss
Anyway i was not saying that you must use a Ge transistor to make a TB, just that the RM circuit can't give a good sound with a Si one.