Home › Forums › Help/Technical Questions › Germanium chips
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October 21, 2014 at 11:24 am #83681Muff DiverMember
Are the germanium transistors EHX are using in their new pedals NOS? Are they as unreliable as the old germanium chips were when it comes to the environment they are used in? The reason I’m asking is because I have the Germanium 4 Big Muff and the Germanium OD pedal and they don’t seem to be affected by the changes in environment that much, at least as far as I can tell. I remember some pedals in the early 70’s using germanium transistors being highly unreliable if it was cold or raining. I admit I haven’t tested them out in really extreme environments, but they do seem pretty stable so far. Any insights from the staff here as to what kind of transistors these may be?
October 23, 2014 at 1:07 pm #120323Mark HammerMemberFirst off, let’s tidy up the terminology: there ARE no “germanium chips”.
Second, consider that, if anyone could or would do it, Mike Matthews and EHX would arrange for production of a limited run of germanium transistors, or at the very least buy up the world’s NOS supply (or close to it) of a given germanium transistor, the way he did with the Matsushita MN3005 for the Memory Man in the 90’s.
That said, there is a LOT of unit to unit variation in germanium trannies, so you’d need to have a large supply of them in order to pick out the usable ones and have a dependable product. Small boutique houses can afford to use varying components, but a major manufacturer risks damage to their brand if they can’t turn out a consistent product that sounds exactly the same at every Guitar Center. Admittedly, this is but one pedal in a VERY large stable of excellent products, but even so, unit-to-unit variation within a pedal can breed some hard feelings and, in tandem with forums, can release a tidal wave of “bad press”.
All of which leads me to ponder that a) there isn’t a whole lot about the pedal that *depends* on germanium, and b) there is no grand plan to have as many of these in the world as there are Big Muff Pi’s. The one confirmed gutshot I’ve been able to find shows that it is mostly a surface-mount board, with what appear to be two pairs of germanium transistors mounted to the board, and a dual op-amp I each channel.
October 24, 2014 at 12:00 pm #120327Muff DiverMemberThanks for the reply, and I do know there aren’t any germanium “chips”. I found this on a site dealing with the fuzz and distortion development timeline:
2010 EHX GERMANIUM 4 BIG MUFF Pi v13
This is a completely brand new circuit design, not based on the common four stage Big Muff circuit at all. The design incorporates two independant circuits based on Bob Myer’s original designs. Each includes two Germanium transistors. The four NOS NKT275 transistors in the G4BM are evaluated in the standard listening QC check that is done with every EHX pedal to determine if the pedals is suitable to go out the door. How long these NOS transistors will be available is unknown.
“The G4BM definitely has its own sound. But with the adjustability of the circuit, you can get a wide variety of tones, including more vintage fuzz tones, OD tones, as well as raunchy distortion. It doesn’t have that great saturation as the Big Muff though, as we were aiming for more of a Distortion/Over Drive type of thing…What we came up with was a pedal that captures the warmth of the germanium sound and is capable of going from completely clean, to warm and smooth, to insane and over the top.” – EXH designer Daniel Shin
So now I’m assuming they both use NOS transistors.
October 24, 2014 at 1:09 pm #120329Mark HammerMemberThanks for that. It’s sort of what I thought I saw in the one picture I could find, but I didn’t want to leap to conclusions. Turns out, the conclusions were right. Chalk up another victory for intuition.
The NKT275 units are preferred germanium units for Fuzz Faces these days. I have no idea what sort of supply is remaining out there, but I’m pretty confident no company as big as EHX would launch a product based on it unless there was some sort of supplier big enough to justify the launch.
The distinguishing feature of the traditional transistor-based Big Muff is that it uses double-clipping. That is, it boosts and clips, then it boosts and clips all over again. The degree of boost used in each stage, and the manner which bandwidth is trimmed or enabled here and there, as well as the width of the scoop in the tone circuit, plays a role in the tonal quality found from issue to issue, not to mention within issues (according to Magic Mike himself in a business mag interview). That is not to say that other designs can’t sound fuzzier, but the sustaining quality of the traditional silicon BMP stems from the design telling the signal “Hold on a sec, I’m not done with you yet”.
The G4BM, in its use of NKT275s, and non-reliance (at least from the gutshot) on diodes for clipping, would appear to be another Fuzz Face derivative. It is nigh impossible to estimate the number of designs derived from the basic Fuzz Face structure utilizing feedback from Q2 to Q1. Over the past 50 years, they just keep coming and coming. And for good reason: it is a very rich test bed for yielding different distortion qualities via small adjustments to bias, feedback, etc. The early Muff Fuzz itself was a FF derivative (albeit with a fixed gain), and the Double Muff might be described as a distant relative of the G4BM by packing in two cascadable Fuzz Face-like circuits.
I have every confidence that EHX has gathered up a sufficient supply of NKT275 trannies to launch a viable product. That said, the supply IS limited. Assuming it hasn’t gone digital by then, I expect to see Big Muff PIs being made in some form a decade from now. The same can probably not be said for the G4BM.
October 24, 2014 at 2:10 pm #120330Fender&EHX4everModeratorI have an old ZVex Fuzz Factory that definitely fluctuated a bit from winter to summer. I actually love when analog gear does that, like analog synths that need to warm up and recalibrate. It’s a delicious reminder of an older era when we appreciated simpler things.
I also have the Germ OD and the Germ 4 BMP, and so far they seem consistent. Awesome pedals!
October 24, 2014 at 2:25 pm #120331Mark HammerMemberI remember there was a schematic posted on the DIYstompbox forum some years back (at least 10, and probably more) for a self-biasing Fuzz Face (used an op-amp for the self-biasing sub-circuit), that compensated for the sorts of temperature, and other fluctuations.
I also enjoy the serendipity that comes with analog gear. But then, I’m a basement noodle, and not a working musician. I fully understand the desire of working musicians to have something that does what you want, in the way you expected, at the time you need it to.
Unpredictable is good…when there is some predictability to it!
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