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Topics - helos

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1
General Questions / Newbie pnp switch help
« on: June 04, 2019, 01:06:42 PM »
Hi guys, I'm having an issue with a switching circuit that I'm using to bypass the fx... The transistor is 2N3906 and it's wired so that when the base is grounded, it activates a (non latching) relay...

The base is grounded through a simple external footswitch.

The problem is that, when the pcb is installed in the enclosure, the Jacks touch the enclosure (grounding it) and this makes the transistor to not work any more...
But when the Jacks don't touch the enclosure it works perfectly...

Why??

Can you help me?

2
General Questions / OD->Boost and Boost->OD switch
« on: May 02, 2019, 11:32:18 AM »
Hi guys! I'm sure you can help... I'm trying to design a pedal with an overdrive and a boost, each one with their switch.

But I'd like to add a toogle switch to choose the position of the boost (before or after the drive), much like the Fulltone Fulldrive 3...

Do you have a schematic for something like this??

Can someone help me?  :-[

Thanks

3
General Questions / Blues Power LEDs
« on: December 14, 2018, 07:08:23 AM »
Hello, do you know what kind of leds are the ones that Jesse Davies installs in these pedals?  :o :o

4
How Do I? Beginner's Paradise. / Led Popping noise
« on: September 10, 2018, 01:06:11 AM »
Hello guys, I hope you can help me!

I wanted to improve my use of Eagle and I had some PCB fabricated for a compressor circuit.
The effect works well except for a little pop noise (actually it's more a "tick" than a "pop") when I switch on the effect.

I'm sure it's the LED, because if I disconnect it from the ground (so that it doesn't light up) there's no noise at all...

I also tried to add a cap and other limiting resistor as shown on Muzique website, but nothing changes...

I'm using a high brightness white led with a 15k limiting resistor tied directly to 9v dc jack (before the diode polarity protection). The negative side of the led is tied to the 3pdt.

I'm wondering if the size of the 9v and ground traces (that go to/from the LED) are somehow related to this... actually the size is 10mils for the ground trace and 15 mils for the 9v.

Could it be due to the LED quality? I used one from China... not the best source I admit...
If so, what LED would you suggest me?

Can someone help me?

Thank you very much!

5
Tech Help - Projects Page / Afterlife diodes
« on: March 14, 2018, 05:52:24 AM »
Hello, I can't find the 1N270 diodes, can I replace them with the 1N34A?

6
How Do I? Beginner's Paradise. / Resistors question
« on: February 27, 2018, 09:02:11 AM »
Hello everyone, my question is probably stupid but I was just wondering if there would be any audible difference if I used good quality resistors (like Vishay) rather than the cheaper ones I can get from Tayda or Aliexpress...

7
General Questions / Relay bypass power supply issue
« on: February 16, 2018, 07:43:17 AM »
Hello everyone,
I'm trying to develop a bypass system based on a relay (Takamisawa na5w-k), I'm also using a microcontroller activated by an SPST switch, all powered by a 78L05 at 5V...
Basically everything works, except for a really annoying pop noise when the relay changes its state.
The funny thing is that the exact same circuit on the breadboard doesn't do any kind of noise... After many tests I've figured out that the problem resides in the power supply.

It must be said that I use a 82R resistor together with a 100uF cap at the input of the power supply, to filter out some high freq. power noise, now:
- if the input of the 78L05 is connected AFTER the 82R (being so connected to the supply rail of the rest of the effect pedal) there's the pop noise when I press the switch
- if the input of the 78L05 is connected BEFORE the 82R the pop noise is very much reduced but not completely eliminated...

Can you help me with this issue??


8
General Questions / Deadringer vs Deadringer 2
« on: November 29, 2017, 05:05:58 PM »
Hello everyone, sorry for asking something about a super well known subject... but I would like to understand why in the deadringer 1, C9 is 10nF and R13 is 47k, while in the deadringer 2, C9 is 4n7 and R12 is 22k... these two components are used to flatten the mids in both circuit... but is there any particular reason for the change of their values?
 

9
General Questions / Opto-Fet switch
« on: September 17, 2017, 09:05:04 AM »
Hello,
I've read somewhere in DIY stompbox forum that opto-fet (like the one used in the Opto Tron switch) could produce distortion when the applied signal exceeds 100mV. Is this real?

So let's say that I have a pedal built with an optical switching system, would it produce distortion if I put an overdrive pedal in front of it? Putting a OD pedal would probabily make the signal greater than 100mV, thus a optical switch would distort...  :-\


BTW, what can you say about the 4N35? Is this a good alternative to the H11F1?

10
How Do I? Beginner's Paradise. / Buffer on power supply
« on: September 02, 2017, 04:59:20 AM »
Hi all,
probably this is "yet another newbie question" but... On some schematic I see an IC wired as a buffer on the power supply, what is it for?

Thanks!

11
General Questions / JHS switch
« on: August 30, 2017, 01:42:29 AM »
Hello guys,
do you know why JHS uses a 3pdt switch in many drive pedals (like the moonshine, charlie brown, morning glory...) wired as a millenium bypass?
Is there any reason for that?
Does the millennium bypass reduces the "pop" noise?
 :o :o

12
VFE Projects / VFE power supply filtering
« on: August 08, 2017, 09:33:22 AM »
Hello guys, can someone explain me what are the differences (and advantages) of using the inductor (1mH) in the power supply filtering section, rather than a normal resistor?

Thanks

13
General Questions / 3PDT pop noise reduction
« on: August 08, 2017, 03:04:13 AM »
This topic has been probably discussed many many times, I've read many articles and posts on different forums so far and I think I've figured out some things the builder should check to remove (or at least reduce) the upsetting pop noise of the 3PDT switch; I'd like to have your opinion on this (maybe I'm completely wrong):

1) Switch quality:
I've done some tests with different 3pdt switches (purchased from Aliexpress, Tayda, Alpha, Hong) and I can clearly notice that cheap switch = loud noise.
Probably due to the following reasons:
- High force required to perform the switching
- Bad bouncing performance
- Bad Internal spring
The only exception is that I've found the Alpha 3pdt to make a louder pop than the Hong 3pdt (with the same circuit), but the Hong is supposed to be a clone (and even cheaper) clone of the Alpha.

2) Pulldown resistors:
The classic 1M pulldown resistor at the input is helping but it doesn't really cancel the noise. A pulldown at the output is also good. Grounding the input in bypass mode improve the noise reduction.

3) Bypass capacitors:
Any (even small) fluttering in the supply voltage could be displayed at the output of the circuit as a little parasitic voltage, that we hear as pop when the switch suddenly change its state. Is this correct?
This is something really interesting that I've not yet tested. In all my builds I've always used 2 sided PCB (with ground plane at the bottom and power plane at the top). I want to try now to assigning Vref (half of supply voltage) to the top plane and manually route the power lines (20 mil width) to let them be as short as possible AND placing the film box type bypass capacitor (not the electrolytic ones) as close as possible to the supply pin of the active components.
This way the inductance should be reduced at minimum and the power supply filtering should be improved.

4) Optical bypass
This is another thing I do want to test: the idea of never really mechanically disconnect the signal from the circuit input could be great, and could make the switching quieter (a mechanical movement is needed only at the output)


These are just some of the consideration I'm thinking of... what's your opinion?
Thank you!  ;)

14
Open Discussion / Coupling Capacitors
« on: August 08, 2017, 02:22:09 AM »
Hello everyone, this is my first post in this great forum.
I'd like to ask you what do you usually use for coupling capacitors. I've seen many builds using only polyester film type, and other using also electrolitic.  ???

Any advise on this?

ps: sorry for my english...

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