Teeny tiny fuzz.

[paul.creedy]

I'm not going to claim creation of a brand new circuit, because I am certain that at least one reply will tell me where this sort of layout has been used before, but it pleases me that it works (the important bit) and sounds fuzzy enough to satisfy its name.



It's a pared-down version of my previous warbling layout that I wanted to try just to see what would happen, after transistor swapping showed me that the circuit still worked even with one transistor missing. It no longer warbles but it's pleasantly fuzzy, with the 100K Lin working as a tone control at the moment with its sweep between 10nF and 100nF

As it's all part of me trying to understand what bits of circuits do, I consider it useful knowledge

[digi2t]

Looks like a stripped down Hyperion.

[paul.creedy]

It was actually stripped down from another of her's, the OK - but I was assuming something so simple may well have surfaced much longer ago.

As a small, self-contained fuzz, I'm wondering what to do with it (if anything) next. I'm assuming it's possible to add it to another circuit to add fuzz to whatever the other circuit does if you can separate the two enough that they don't make each other behave wildly different to how they would in isolation (unless that's what you're after).

IIRC I read somewhere that finishing a circuit with a capacitor helps prevent voltage traveling out via the jack socket, is that correct ?

(I have a supplementary question which I will ask in a separate thread)

Would a blend pedal allow fuzz at one extreme, what ever effect might be on another board at the other and both circuits equally in the middle ?

I'll make it clear again that I'm new to all this so apologies for asking potentially idiotic questions

[paul.creedy]

Looking at that Hyperion schematic, are some or all of the 100nF caps to the right of Q1 keeping the two sections that appear to be receiving separate inputs of 9v apart to some degree ?

Looking at a stripboard (or do folk prefer "vero"?) layout to build a Hyperion I can see how this is done, so I'd be grateful to find out if this is the case, and why.

[ElectricDruid]

IIRC I read somewhere that finishing a circuit with a capacitor helps prevent voltage traveling out via the jack socket, is that correct?

It's true that adding a capacitor at the end blocks *DC* voltage, but it doesn't block AC signals like a guitar.

I'll make it clear again that I'm new to all this so apologies for asking potentially idiotic questions

A teacher of mine used to say that the only idiotic question is the one you don't ask. Asking lots of dumb questions is usually the sign of intelligent people learning something new. The *really* dumb people don't ask because they're afraid of looking stupid, and so they never learn anything. So keep 'em coming!

Tom

[ElectricDruid]

Looking at that Hyperion schematic, are some or all of the 100nF caps to the right of Q1 keeping the two sections that appear to be receiving separate inputs of 9v apart to some degree ?

Yes, exactly. There's a 100nF cap at the input separating the first stage's DC state from whatever you plug into it, then there's two more in-between the two stages (could have used a single cap in this position - two in series just halves the effective value) which separate the DC biases of the two transistors, and then there's another one on the output to separate the second stage from whatever follows it (the volume control and whatever else you plug in).

[paul.creedy]

Thank you for that

I always felt that I had reached a degree of maturity when I recognised the value of being prepared to show I either hadn't understood or lacked some essential knowledge by asking a question, as you say you gain nothing by keeping your ignorance to yourself.

It's been a long time since I took time to learn something just for the enjoyment of acquiring an understanding of a subject, and this has the added bonus of adding to my pedal collection at the same time

I've previously gigged on both guitar and bass that I built myself, so there is also a pleasure to be taken from creating something from its component parts too.

[rankot]

Why 100n capacitor from Q1 collector to ground followed by two 100n caps in series? Some kind of low pass filter?

[ElectricDruid]

Why 100n capacitor from Q1 collector to ground followed by two 100n caps in series? Some kind of low pass filter?

It's a Devi Ever circuit isn't it? So it doesn't have to have a reason...

[duck_arse]

one thing about your circuit diagram - you really should show which lead is the emitter, by adding the emitter arrow. this then shows the polarity of the transistor [pnp or npn] as well. so, two things.

oh, and probably if you draw the base connection of the 2N2907 sticking out the right of the base, then down and across and up to the base of the MPSA, the diagram may appear less confusing to the youngens. ok, three things.

[edit]

one last forth thing - you should habitually fit a pulldown resistor from the wiper of the input pot to ground, say a 1M, in order to reference those two input caps to ground and to help prevent popping when bypassing.

[paul.creedy]

one thing about your circuit diagram - you really should show which lead is the emitter, by adding the emitter arrow. this then shows the polarity of the transistor [pnp or npn] as well. so, two things.

oh, and probably if you draw the base connection of the 2N2907 sticking out the right of the base, then down and across and up to the base of the MPSA, the diagram may appear less confusing to the youngens. ok, three things.

[edit]

one last forth thing - you should habitually fit a pulldown resistor from the wiper of the input pot to ground, say a 1M, in order to reference those two input caps to ground and to help prevent popping when bypassing.

1 - Noted - I was being hesitant about what the arrows signified (see #2).
2 - Noted - in the Hyperion diagram above, does the arrow facing one way on the MPSA18 and the opposite (if the image was flipped) on the 2N2907 show that one is NPN and the other PNP ?
3 - Noted - I was following another diagram similar to the Hyperion, but I did notice you did things differently with your souped-up circuit.
4 - Noted - I haven't had any issues so far, but I do recall a supposedly pro pedal that made a terrible pop when switched on and off, so I'm aware of what could happen.

So much to learn, so much fun!

[duck_arse]

as the great man [kipper4] once taught me - Not Pointing iN = NPN. and the other one is PNP, which does point in. for 30 something years, I'd have to look to see what a BC548 was to tell whether I was pointing in or out.

the arrow also appears on the jfet symbol. and the diode symbol. and the mosfet symbol. and the scr, the put, the ujt and the etc.

[antonis]

Why 100n capacitor from Q1 collector to ground followed by two 100n caps in series?

Perhaps the designer didn't have neither 50nF (nor 47nF) cap handy..
(on the other hand, if last cap right leg was grounded, instead of connected on MPSA18 Base, it should be an interesting LFO-ish fuzz..)

[rankot]

I'm not sure I get this