Newbie questions

Started by nerdy_donkey, August 08, 2014, 03:25:36 AM

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nerdy_donkey

Hello guys, I've recently gained interest into DIY-ing effects pedals. Thanks for keeping a friendly forum filled with information I'm hoping to learn to build from the very scratch and get lotsa guidance from all you gurus here.

Before I start, I would just like to 'de-mystify' a few things that I have always wanted to know about delay pedals as I would ultimately like to build something complicated like a delay with tap tempo:
1) Certain delay pedals have a jack for you to connect an external tap pedal to control the tempo. I've always wondered how this works as the tap pedal is not powered yet it could send the tap pulses to the delay pedal. Can someone explain this to me please?
2) What is the difference between normal jack out for tap tempo and TRC jack as found in Strymon pedals?
3) When IC chips are involved, the operating voltage for the chips are usually lower than 9V. How do we effectively pull down the voltage that is being fed into the chip without frying it? I know we can use resistors to bring down current but can we also use resistors to bring down voltage?
4) I've seen a fair bit of schematics online but I'm wondering if there are schematics with explanations to explain what each section does? I don't need explanation on each of the components, just how the different groups of components work to achieve different features in the pedal and combined to give you one complete pedal.

I hope these questions make sense. They might sound stupid but I'm a total newbie here so I'm looking forward to seeing your replies! Thanks in advance.

-Yong

nocentelli

#1
Welcome to the forum.

1) A tap tempo jacks is usually just a mono jack connected to two points on the pcb: The tap tempo switch is usually just a "normally open" momentary switch: Tapping it once closes and opens the switch. Tapping it twice allows the digital circuitry to "measure" the duration between taps and convert this into the delay time. Exactly how it does this varies from circuit to circuit. There are tap tempo "add on" kits for the diy-er, and the documentation that accompanies them will explain further. If you search for "Electric druid tap tempo" you should find some good stuff.

2) TRS (tip ring sleeve) are stereo: I'm not sure that the strymon has been traced: I don't know how a TRS tap jack might work.

3) Digital chips often run on 5v: A 5v regulator is a small component, very similar in appearance to a transistor with three legs - 9v (or whatever) goes into one leg, the middle leg is grounded, and a steady 5v comes out of the other leg. You could also use two resistors as a voltage divider, but there are drawbacks.

4) There are many schematic walkthroughs around, but they tend to be for simpler circuits than a tap tempo delay. Nonetheless, they are a good starting point for understanding guitar pedal circuits in general. Google "RG keen technology fuzzface" or "kitrae big muff circuit" or "beavis LPB1 circuit" for three detailed explanations of legendary vintage circuits.

Good luck with your DIY endeavours!
Quote from: kayceesqueeze on the back and never open it up again

bluebunny

Quote from: nerdy_donkey on August 08, 2014, 03:25:36 AM
Hello guys, I've recently gained interest into DIY-ing effects pedals.

Welcome!  You'll never get out alive...  :D

Quote
. . . get lotsa guidance from all you gurus here.

Ha ha!  Flattery will get you everywhere.  Never been called a guru before... ;)

Quote
3) When IC chips are involved, the operating voltage for the chips are usually lower than 9V. How do we effectively pull down the voltage that is being fed into the chip without frying it? I know we can use resistors to bring down current but can we also use resistors to bring down voltage?
4) I've seen a fair bit of schematics online but I'm wondering if there are schematics with explanations to explain what each section does? I don't need explanation on each of the components, just how the different groups of components work to achieve different features in the pedal and combined to give you one complete pedal.

I'll let some other learned folks stop by with answers for some of your questions.  [Edit: Leo just did, as I was typing!]  As for 3), the operating voltages for most of the chips we play with (mostly op amps) are way more than 9V.  Off the top of my head, the TL072 will do +/-18V - that's 4x 9V.  But for the second part of that question, resistors drop voltage not current.  If they dropped current, electrons would mysteriously be disappearing somewhere within the resistor and the Universe would stop.

To get you going with 4), try this one for size: http://www.beavisaudio.com/techpages/HIW/HIW.png.  Lots more examples out there.  I'm sure others will post their favourites.

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I hope these questions make sense. They might sound stupid but I'm a total newbie here so I'm looking forward to seeing your replies! Thanks in advance.

No stupid questions.  Just watch out for the stupid answers!  ;D  (I hope I'm not guilty of that one...)
  • SUPPORTER
Ohm's Law - much like Coles Law, but with less cabbage...

Elijah-Baley

If you are searching some easy circuit I realized, as first project to practice, a smokey amp on veroboard.
Then, a clone mxr micro amp booster. The circuit works well, but now I have some trouble with the wiring.  :(
Actually I don't really need of this booster, but I need to learn many things.
Maybe you could to follow my way.

Good Luck!
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

slacker

Quote from: nerdy_donkey on August 08, 2014, 03:25:36 AM
2) What is the difference between normal jack out for tap tempo and TRC jack as found in Strymon pedals?

As far as I know the jack on Strymon pedals isn't for tap tempo it takes an expression pedal or volume pedal allowing you to control one of the parameters with your foot.

deadastronaut

our friend chromsphere (paul) on here covered the strymon tap tempo..

https://www.youtube.com/watch?v=NKo1qoOu0ww

watch some of his other videos, he's a cool guy, and covers some do's and don'ts too... 8)
https://www.youtube.com/user/100roberthenry
https://deadastronaut.wixsite.com/effects

chasm reverb/tremshifter/faze filter/abductor II delay/timestream reverb/dreamtime delay/skinwalker hi gain dist/black triangle OD/ nano drums/space patrol fuzz//