deep trip bog fuzz

[bluebunny]

It must be a wallaby, mate.  Unless, of course, the Austrians have got something to hide?  I hope they've not been secretly breeding skippy and his mates to go into Schnitzel! 

[BetterOffShred]

would something simple like this low pass right before the volume at the end before the output buffer work for one?



I jacked that from the Pixel schematic bee tee dubs..

[PRR]

> but .... the secretary general,.....

Politician. Don't believe him.

Anton was re-caught but others bounded away in Austria:
https://www.thelocal.at/20160707/escaped-kangaroo-evades-police-in-austria

[PRR]

> would something simple like this low pass

That low-pass needs a series resistor. If you didn't lose one off the left side, you need one.

Sorry for hopping away from the topic.

[Austrian]

> but .... the secretary general,.....

Politician. Don't believe him.

Anton was re-caught but others bounded away in Austria:
https://www.thelocal.at/20160707/escaped-kangaroo-evades-police-in-austria

Yes, for Skippy it was a long, difficult journey from Australia to Austria.
But he is all hopped himself!

[BetterOffShred]

> would something simple like this low pass

That low-pass needs a series resistor. If you didn't lose one off the left side, you need one.

Sorry for hopping away from the topic.

Is that because it's 1/(2*pi*R*C) for cutoff frequency and mathematically speaking if R or C goes to zero the frequency becomes infinite, so we have a series "limiting" resistor to set the high end ? Sorry if that's a dumb question. I'm trying to learn this stuff Hah!

[Menegozzo]

Hello, guys! I'm Du Menegozzo, Deep Trip's main man. I'm glad you guys are interested in our BOG! It was pretty much the first one that got us into pedal making, exactly ten years ago, in 2007. Considering we haven't been making that version since 2010, I'd like to correct a few mistakes on the schematic that will impact the tones enormously, may I? I'm looking at the first image posted as a reference.

First, the 470k resistors to ground at each switching point are all 4M7 on the original units. And there are a few missing: input and output of the first buffer, input of the FF part. Those will greatly minimize switching noises (although they could have been smaller, we used 4M7 at the time).
The 47k in series before the SW2 is actually 4k7.
The 47n is not at the base of Q2, but in parallel with the 1k2 resistor.
The 100k feedback resistor, as you guys spotted, should go from Q2 emitter to Q1 base, like a traditional FF feedback resistor.
The 120r resistor with the "Fuzz" pot is 12r.

Not all early BOG units are exactly like that: the first ones didn't have the output buffer (those had dark red goop on the boards), some of them had slightly different values and transistors.

Like Mark Hammer said, transistor hFE may be critical and the trimpot is there to adjust biasing for both transistors. It will completely change the range of the "Mood" control, so keep an eye on what you get there, mainly at the extremes. I like to have the perfect wave symmetry at the middle of the travel, I find it pleasing to the users that aren't into the tech details.

At Deep Trip we don't like to stick with the usual suspects, so you won't find any BOG units with BC108 or BC109 out there, same for the other models. We did several weeks of testing for transistor types and hFE ranges before we settled for each model (the germanium transistor units even had different types for each position, carefully chosen).

And we always liked to explain exactly what was inside the box, you won't find a description stating the BOG is a completely new revolutionary circuit, same for any other model that is based on old stuff. We were always completely honest about what we were doing (and I truly believe that the fact we're still alive and growing after ten years has something to do with that).

Have fun experimenting and keeping DIY alive! See ya!
-
Du Menegozzo

[BetterOffShred]

Well thank you for that information Du!  I didn't even know this pedal existed until this thread and now I'm somewhat consumed by it.  It does the things I like and I'm going to try to get it going.   My hat is off to your device and I also appreciate that you give credit where it's due.   

So back to the circuit for those of you who are still looking.  I took another wack at adding a high and low control .. hand drawn because I don't have cool software for schematics as of right now.    I didn't calculate any frequencies for the high pass, I am not sure it's right, I just jacked a simple low control from another fuzz variant that had similar topology.   That being said, wouldn't it still need a series resistor (the one with the blue arrow and question mark) ? Would the high pass be more effective earlier in the effect?   



Love to hear back

[Austrian]

Hi Du,

Thanks for your comment. Your pedals are just great.

Greetings from Vienna, Franz

[KarenColumbo]

Slightly off topic - but since I'm not the only one (wallabies et al) I'll chime in with a hearty "seawas!" from good old Ottakring! Good to know there's an Austrian building force in existence.

[Austrian]

Slightly off topic - but since I'm not the only one (wallabies et al) I'll chime in with a hearty "seawas!" from good old Ottakring! Good to know there's an Austrian building force in existence.

Na dann, geht das Seawas natürlich zurück.
Da fühlt man sich gleich ein wenig heimeliger, mit einem Landsmann ;-)

LG Franz

[antonis]

> would something simple like this low pass

That low-pass needs a series resistor. If you didn't lose one off the left side, you need one.

Sorry for hopping away from the topic.

Is that because it's 1/(2*pi*R*C) for cutoff frequency and mathematically speaking if R or C goes to zero the frequency becomes infinite, so we have a series "limiting" resistor to set the high end ? Sorry if that's a dumb question. I'm trying to learn this stuff Hah!

A low pass filter needs a series resistor and a shunt capacitor..!!

In your scheme, it's a HIGH pass one 'cause voltage dividing point (lug 3 of Vol pot) only "sees" C6 in series with signal and Low Pass pot + C5 shunting it..
(C6 as upper and 100k+C5 as lower part of voltage divider..)

Placing a resistor on the left side of C6 you actually create a LOW pass filter in the way of the higher the frequency the lower the resistance (capacitive reactance) of BOTH caps...
(same "easiness" for series and shunt signal passage/lost..)

Maybe I've confused you so it should be better to look at it as (Rx+C6)/(100k+C5) BOTH region frequency variable voltage divider..
(and leave you to decide if it's Low-pass, High-pass, Band-pass or Band-reject, depending on specific component values..)

[radio]

@Menegozzo:

     When will the BOG be available again?

     Because I feel more inclined to buy a pedal thats still in production!

     Thanks for any answer!

[abc1234]

A low pass filter needs a series resistor and a shunt capacitor..!!

In your scheme, it's a HIGH pass one 'cause voltage dividing point (lug 3 of Vol pot) only "sees" C6 in series with signal and Low Pass pot + C5 shunting it..
(C6 as upper and 100k+C5 as lower part of voltage divider..)

Placing a resistor on the left side of C6 you actually create a LOW pass filter in the way of the higher the frequency the lower the resistance (capacitive reactance) of BOTH caps...
(same "easiness" for series and shunt signal passage/lost..)

Maybe I've confused you so it should be better to look at it as (Rx+C6)/(100k+C5) BOTH region frequency variable voltage divider..
(and leave you to decide if it's Low-pass, High-pass, Band-pass or Band-reject, depending on specific component values..)

Are you saying that low pass filter won't work without a resistor on the left side? Because I've built circuits with similar low pass filters (i.e. cap to ground and no series resistor) and they work.

Here's that low pass filter in action (at 2m20s):

[BetterOffShred]

Yeah I built a pixel, and the lowpass definitely works and is noticeable as shown in that circuit snip I added a ways back

[antonis]

 

Maaaaaaybe because THERE WAS a "left side" series resistor...
(resistance of whatever it was driven from - unless you've obtained the perfect voltage source..)

[abc1234]

Maaaaaaybe because THERE WAS a "left side" series resistor...
(resistance of whatever it was driven from - unless you've obtained the perfect voltage source..)

OK, I'm confused. You're now acknowledging it isn't a "HIGH pass" filter and it doesn't need a "series resistor" because what comes before it provides the resistance... Did you not read the schematic (of either the Bog Fuzz or Pixel) and see what it was driven from?

[antonis]

You're now acknowledging it isn't a "HIGH pass" filter and it doesn't need a "series resistor" because what comes before it provides the resistance... Did you not read the schematic (of either the Bog Fuzz or Pixel) and see what it was driven from?

Maybe you didn't read carefully what I've wrote...

I said it isn't a LOW pass filter...
(at least, not with a series resistor before it - if you consider C5 as short at high frequencies it's a classic HIGH pass filter)

Elementary view on simple RC filters is obtained by ignoring (considering negligible) resistance and capacitance set before & after them and is restricted only on their specific R/C arrangement..
(which item is set in series and which is set in parallel..)

In real world, there aren't "pure" High-pass or Low-pass filters.. 

[BetterOffShred]

This is why I got a mechanical engineering degree instead of electrical engineering   

I'll probably just breadboard what I drew up and see what happens. I'll also make sure I use Du's amendments.

[Hatredman]

@Menegozzo:

     When will the BOG be available again?

     Because I feel more inclined to buy a pedal thats still in production!

     Thanks for any answer!

The BOG is still in production, it was never discontinued.

Buy yours at deeptripland.com

.