mojo - where do you draw the line?

[chromesphere]

Its a fine line isnt it? Whats acceptable mojo and whats not? It can get taboo. There appear to be a select group of acceptable components that are fine to tout as good sounding parts but others that are not acceptable to even use amongst pedal builders (like in the recent em drive thread -> Russian caps). The thing is...the best sounding rangemaster ive built so far was my Russian nos cap + carbon comp resistors rangemaster kit. I compared it to a 'tayda' rangemaster, same biasing, same ge trannie, and I liked it better! the distortion / noise created by the old components gave it loads of character. I have a video of this . May finally upload one day.

So for you,  where does the corksniffing begin? Whats worthwhile experimenting with and what will you just not touch at all? Transistors? Caps? Resistors!? DIODES!!!??

This subject interests me as there are such divided opinions and I hope people will argue violently.

[DutchMF]

This is going to be a fun thread! I think all mojo is acceptable, as long as one can appreciate it for what it is and doesn't forget to use ones ears. Like in your case, if it sounds better, it sounds better! The only reason I 'mojofied' my recent Weener build was because I thought it was fun to do, not to chase some elusive perfect wah sound. To summarize: keep it fun and use your ears!

Paul

[croquet hoop]

Regarding the "sound" of carbon comp resistors, I read something a few days ago that explained when and why they would sound different, e.g. "good" for our ear. I think I found the link on this forum. It was interesting.

Regarding mojo, I think it is fun to make/have pedals with different/rarer components, but my stance is generally that the more pedals/processing there is in a signal chain, the less noticeable any change of component will be, so I do not bother much (as a matter of fact, I just received Bosstone boards from OSH Park, made for metal film resistors and 5 mm caps; it almost looks boring, but I find it quite fun).

I'd rather throw $10 for a nice switch than the same price to replace standard parts with elusive ones. With the switch, I'm not relying on a placebo effect to appreciate the change.

[juansolo]

I only mojo stuff up for tartiness sake. Not for any sonic reasons.

[culturejam]

I firmly believe that if you like it, then it is "acceptable"...regardless of the reason. 

I've used caps and resistors and transistors just because of the way they looked. Tants look cool. Carbon comp resistors look cool. Metal-can and "flying saucer" trannies look cool.  Box caps look cool. Axial non-potted inductors look cool!

If I wanted to build the same pedal with the same sound on an ongoing basis and with a moderate degree of consistency, I would select the highest-tolerance, lowest-noise parts that are reasonably priced. 5% caps / 1% resistors / silicon transistors are all plenty "good enough" for consistency from pedal to pedal. And I would only choose current-production parts, except in cases where the existing volume of product is very high and the price is also reasonable.

But for fun one-off DIY stuff (which is really the whole point, isn't it?), anything goes. Whatever kind of parts you throw in the box will work and sound *basically* the same as any other set of parts (assuming values are the same).

[midwayfair]

Oh man.

I'd like any audience members with sensitive dispositions to leave the building now. I don't think it'll be an unpopular opinion, but you never know ...


...


I'll just go through individual parts ...

Resistors

RG Keen did an excellent article on Carbon Comp resistors, which is fortunate because I don't have the equipment to test this. They are capable of introducing resistor distortion at VERY high voltages. This property CANNOT occur in stompboxes. I'm not saying "is likely inaudible" or "maybe a little once in a while." It is literally impossible to produce this property in a stompbox running on 9, 12, 15, 18, 24, or even 30 volts, which I imagine is every guitar pedal and almost every rack unit ever created.

I did matched resistor replacements one at a time and could not hear a difference except a little added noise. That was good enough for me.

Notice no one claims that carbon film resistors have mojo? Maybe it's because they just weren't used during a period of time where people think everything had mojo.

Now you want some REAL mojo, get spendy and find glass resistors. Those things look frigging awesome and are super rare and expensive. I never was able to get enough together for a treble booster, but I really wanted them for an all-glass-and-metal booster.

Capacitors

There's another RG Keen article where he examined capacitor types and scoped them. This is another thing that only appears when you have enough voltage and bandwidth to produce changes.

Most of the capacitor mojo ends up being applied to guitars, where it is utterly and completely absurd. A lot of multimeters (including mine at home) don't measure capacitance, and capacitors have horrible tolerances, so it gets particularly laughable when people swap them out in a guitar or something and say, "look, this one sounds so much WARMER" (and man what a stupid word that is). Add to that the fact that the human brain is incapable of remembering a sound for more than 2 seconds (which is surely longer than it took you to switch that cap in your guitar) and it's <shakes head> time. In particular, because it's an RC filter, differences between caps become even less noticeable the second the guitar's tone pot is adjusted.

However, caps really do sound different in the right circumstances. Some electrolytics have less internal resistance, so they actually work better, which can be important for filtering out noise. Ceramics really do introduce distortion when working with enough voltage (not the couple hundred microamps your pickups). Film caps have reliably good performance. Some paper in oil caps really do have the lowest distortion of any other types of caps.

But like resistors, most people building mojo-riffic products, and dare I say it most people building their own stompboxes with mojo parts, get it into their head that some type of capacitor sounds better, so when they go to test it OF COURSE it sounds better, and you will never be able to convince them otherwise, even if you run it through a scope with matched capacitance. Suddenly it'll become the Emperor's New Ears, or "the scope isn't sensitive enough" (!), or something like that.

Transistors
Yes, germanium transistors sound different from off-the-shelf silicon transistors. And I say this as a lover of germanium. But the reason is that they just happen to have some properties (mainly leakage) inherent in their construction. You can fake leakage. You can match the lower gain characteristics (it's tough getting low-gain silicon, but nothing says that you have to max out the gain on any particular transistor ...). There is really only one property of germanium that can't be faked with a couple extra passives, and that's temperature drift -- a characteristic that we usually take measures to minimize or eliminate!

Germanium transistors ARE useful in that different types might have more of a particular property that you need without needing the extra parts (usually a treble bypass and an adjustment of the positive bias resistor). Use them for that reason. Don't use them because you think germanium is some magic spice. It isn't.

Diodes

Let's all have a nice laugh at Am for tracking down some super rare silicon diode and buying all of them up because they think that forward voltage can't be matched with other diodes.

Germanium diodes also have leakage, which results in a softer knee. If you want to fake this with schottky diodes, you can use some small amount of resistance in series with the diodes.

Temperature drift is, again, not generally considered a desirable characteristic by anyone.

...

For the most part, mojo is almost entirely about the idea that older components somehow sound better. You can always introduce flaws intentionally. Even a lot of cheap modern parts are made better than older parts, but the high-quality components now are worlds better and more reliable. Every time I see someone posting that the carbon comp resistors are what makes their pedal sound so good I want to ask them if they're typing their build report on an Apple 2 or a Commodore 64.

[GermanCdn]

I really have to stop reading Jon's posts at work, my guttural sounds of agreement are getting hard to explain, but very well written.

Back to the topic on hand, given the high number of components and the fact that they all have cumulative tolerances, mojo is probably more happy accidents than design or perception, regardless of how many unicorn tears are dropped on the input buffer.


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[juansolo]

I've just made a fuzz with axials and carbon comp resistors because a) it looks cool and b) I already had them That's it.

[culturejam]

Yes, germanium transistors sound different from off-the-shelf silicon transistors. And I say this as a lover of germanium. But the reason is that they just happen to have some properties (mainly leakage) inherent in their construction. You can fake leakage. You can match the lower gain characteristics (it's tough getting low-gain silicon, but nothing says that you have to max out the gain on any particular transistor ...). There is really only one property of germanium that can't be faked with a couple extra passives, and that's temperature drift -- a characteristic that we usually take measures to minimize or eliminate!

The one thing I don't think you can "fake" is the much lower Base-Emitter forward voltage.

[midwayfair]

Yes, germanium transistors sound different from off-the-shelf silicon transistors. And I say this as a lover of germanium. But the reason is that they just happen to have some properties (mainly leakage) inherent in their construction. You can fake leakage. You can match the lower gain characteristics (it's tough getting low-gain silicon, but nothing says that you have to max out the gain on any particular transistor ...). There is really only one property of germanium that can't be faked with a couple extra passives, and that's temperature drift -- a characteristic that we usually take measures to minimize or eliminate!

The one thing I don't think you can "fake" is the much lower Base-Emitter forward voltage.

Do they? Last time I measured germanium transistors they had a .6v Fv just like silicon. But it's been a while and maybe I dun it rong.

You should be able to fake that, though: Strap a diode across the base to emitter. (Arranged like the 9.1v zener in Mosfets.) Fv divides in parallel (er ... sorta, but I don't know what the formula is).

[pickdropper]

nominally, Ge transistors have a 0.3v drop whereas silicon have 0.7v.  As you've observed, that isn't exactly where everything is.

[jimijam]

personally I think nuthing is uglier than a stompbox with a bunch of 600v caps and several feet of cloth covered pushback wire. mojo my ass.

[icecycle66]

I draw the line at sweet copper.

[chromesphere]

I sit firmly on the fence. All of what jon says makes logical sensd to me....but then there was that rangemaster...mojo-reffic. Sounded totally different to the tayda rangemastsr.  Some may have liked the tayda rangemaster better, cleaner I guess.  I honestly thought I was going to be one of them.  But alas, it sounds a little lifeless compared to the mojo rangemaster. I cant explain it. A oscolloscope cant explain it.  I wish I had uploaded the video so I could show u all what im taLking about.

I think blanket statements like 'dont bother with x component because its a waste of time' is limiting yourself.  Diodes. Dont get me wrong. I think you can hear bugger all difference between 2 diodes with the same fv.  But if you can get say..old 1n34a FOR A REASONABLE PRICE I would perfer those instead of rolling the dice with modern ebay/tayda type that are unreliable.

Generally for me the scientist within thinks its all a load of bs....but...im still keeping my mind open to possibilities instead of shutting out information because I read something that told me I shouldnt bother.

Yeah on the fence.

[jkokura]

I don't 'believe' in mojo in the sense that some parts are better because they are older, rarer, extinct, or somehow have inherent 'majick' to them. However, I do believe in another sort of Mojo.

Have you ever held a guitar and it just blew you away, not because of it's name, or it's reputation, or even of it's cost, but because it was a special instrument? It just screamed 'play me,' and you felt like you could be a better, more creative, more inspired musician if you owned/played through it? There's the mojo I believe in. I believe that there are special elements to certain pieces of gear. Sometimes they're historical, sometimes they're personal, and sometime's they're just something you can't define.

I like my mojo infused, axial caps and carbon comp companion fuzz. Why do I like it? I think it looks cool inside, and it looks cool outside. It sounds cool, and yes I 'believe' it sounds better than the cheapest parts used standard build NOT because they are 'better or mojo' parts, but because I want it to be a better pedal. Why do I believe that? Because I play better and like what that pedal does for me when I make MUSIC.

Sure, there's BS marketing out there. But there's a reason why Bonomassa plays his 59s, and there's a reason we're seeing a resurgence in old, mass produced, russian tall font Big Muffs, and there's a reason why Mayer chooses a Dumble and a standard Fender to simultaneously play through. It isn't the cost, or the 'value,' or the rarity - it's the mystique, the special 'je ne sai quoi' that makes using them feel special.

I rest my case. Jon, you're right, but you're wrong. You're right - mojo is 'sometimes' about old/rare/certain types of parts that sound better. But you're wrong because that's not what most people mean about mojo, and that's real man.

Jacob