Messages

Ok thank you very much guys! 

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...

We had a similar problem with our switching system with Function FX. Our setup is slightly different but we found that rather than running the regulator after the DC filtering used for the audio portion, tying it directly to the PS with a 1N4001 in series with the regulator input fixed the problem. Also, you can try incorporating a temporary mute at the circuit output if you haven't done so. And, also check to see if your LED switching on/off is contributing.

Thank you very much Bryan

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??

Understood.

I explain better my situation: I've already built a DR2 and I really like the mids scoop given by the 4n7 / 22k. Now I would need to build another one but with a Gain Boost footswitch, so I think that the DR1 could be perfect for this, but I want the mid scoop to sound just as the DR2... So should I use the same 4n7/22k of the DR2, or, because of C5/R7 (in the DR1), I should use the 10n/47k values?


furthermore: what is the purpose of C5/R7 in the DR1?? Couldn't I just connect the gain and boost pots in series?

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?

Put the two pots in series. To prevent pops, set it up like the Deadringer. Have a look at the schem in the Deadringer project file. You want to add R7 and C5 from there. You can put the resistor and cap directly on the switch, too.

Hi! Sorry for replying to this old topic... I was just wondering about those R7 and C5 components... Are there just to prevent pop noises when the boost is activated? can R7 be omitted? If so, when the boost is ON and set all CCW, it is exactly the sound of the basic Fulldrive...

I've used the optotron and the Lumen many times. I have to admit that I haven't put an OD in front of it but I've certainly put fuzzes and all kinds of stuff with no distortion.


Sent from my iPhone using Tapatalk

Ah ok... that reassures me a little 
What's the Lumen? I've never heard about it...

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?

This might help:

Voltage Follower Biasing: This method is exactly the same as the voltage divider biasing, except it uses an op-amp (or transistor) to buffer the bias voltage, so choosing small resistor values is no longer necessary. This can help reduce power consumption in a circuit, and give even more accurate gain and offset values, as the impedance the biasing op-amp will present to the rest of your circuit will be infinitesimal compared to any other method. It can also supply a very stable bias voltage to any number of circuits, and will eliminate any cross-coupling of signals between circuits, which might be problematic with a simple voltage divider biasing scheme.

From: https://ocw.mit.edu/courses/media-arts-and-sciences/mas-836-sensor-technologies-for-interactive-environments-spring-2011/readings/MITMAS_836S11_read02_bias.pdf

Very interesting article! Thanks! 
So a buffered voltage reference would always be better than just the standard only-2-resistor voltage divider? Or are there some specific cases where a buffered Vr is recommended?

Usually for a reference voltage.

Ok... but what is it for? Does this buffer act as a regulator? Or what?

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!

+1 on the layout methodology.

I've been quite taken with both opto and relay based switching, and while 3PDT switching is hardly a deal breaker for me, I've been going thru my live rig and replacing a lot of them with CODA and 1776 switching systems where practical.

I'm watching this thread though to see what comes up.

Have you noticed some particular improvement by replacing the 3pdt of your pedals with the optical bypass systems? if so, what kind of improvements?
Many times I read "3pdt are not reliable, and THEN I choose to use the optical bypass system"... but also a 2pdt has a (fairly comparable) failure rate of a 3pdt... so where's the deal?

In your experience: do you think a pop noise could be also a consequence of the PCB design? Using the power and ground planes, if the traces fragment too much the continuity of these planes, a pop noise could be induced when switching on the pedal the first time. Could it be possible?

Can't really speak from experience on this since I never use power planes (just ground planes top and bottom). Bad PCB design could cause several issues including noise and excessive parasitic capacitance. Maybe those could contribute to switch pop. But, designing a good PCB isn't terribly hard and I think most of the DIY'ers do an excellent job (I'm hardly the authority here). I guess there are other variables, too, like power supplies, other effects in the chain...maybe even cabling. But the likely culprit is usually a tiny amount of DC getting amplified through a circuit via mechanical switching.

Thanks.. Well, it would be awesome if you guys could do some sort of PCB design techniques tutorial. I don't mean how to design a PCB with some special software and to output the gerber, I mean how to place the components, where and why.

It'd be great...

Bypass is over-rated anyway. Just leave all the pedals on all the time I say.