freestompboxes.org

Hi,
I'm new to pedal building and I was trying to build this on my breadboard. This is my first time doing a breadboard layout and I'm having a little trouble getting the pedal to work. I'm getting no sound right now, and I'm not entirely sure what it the problem. I looked through the layout and everything appears to be connected. I was a little confused as to how to insert the pot. Right now wires 1 and 2 are in the same row as the input capacitor, and the other wire is in the same row as the 2.2m resistor. Is that right? The other things I wasn't sure about is that I used a LED as a replacement for the 12v zener, and a 1N4001 diode as a replacement for 1n5819. I thought I read that that is ok to do, However, when I touched the 1n4001 it was very hot. Also, I didn't use a bipolar capactior. There was another schematic posted that didn't use a bipolar capactior so I positioned the capactiro in the way that schematic suggested. Any suggestions to would could be wrong would be great. Thanks in advance.

If the 1N4001 is getting hot, then something is very wrong. It should stay cool all the time.
A connection must be shorted somewhere. I would look for something accidentally connected to ground after the 4001. Do you have the 47uF filter cap after it? Perhaps that cap is damaged and shorted?

I'll check that out. The other thing that seemed sort of funny to me (keep in mind that I'm completely new to this) is that the only thing connected to the positive side of the power strip was the 1n4001 diode. Is that the way it is supposed to be, or am I missing something?

PedalPlayer wrote:I'll check that out. The other thing that seemed sort of funny to me (keep in mind that I'm completely new to this) is that the only thing connected to the positive side of the power strip was the 1n4001 diode. Is that the way it is supposed to be, or am I missing something?

That doesn't sound right. Connect the positive lead of the battery to the Anode end of the 4001, and connect the Cathode end of it (that's the side with the band marked on it) to the positive strip of the breadboard. Then, connect the positive lead of the 47uF filter cap and one end of the 5K1 resistor to the positive strip.

Ok, thanks. I'll try that out and report back.

I was trying to work this out, and am just getting a little confused. If the positive side of the cap and the resistor are both connected, what is the cathode of the diode connected to? Would it be possible to just connect the positive side of the cap to the cathode of the diode? Also, what is the middle lug of the pot connected to? Thanks for all the hope, I really appreciate it.

PedalPlayer wrote:I was trying to work this out, and am just getting a little confused. If the positive side of the cap and the resistor are both connected, what is the cathode of the diode connected to? Would it be possible to just connect the positive side of the cap to the cathode of the diode? Also, what is the middle lug of the pot connected to? Thanks for all the hope, I really appreciate it.

Improving your schematic-reading skills will help a lot. The answers to your questions are in the schematic.

If you really want to learn for yourself, stop reading now.


However if you love your family, don't want to get any deeper into this time-leech of a hobby, don't want to learn any more, and just want some quick answers, continue reading below:









-The cathode of the polarity protection diode connects to both the positive side of the cap and the top of the resistor ("top" in reference to the schematic drawing). This is shown in the schematic with a black line connecting each of these components. The line represents a wire/conductor, so if the schematic wire touches three points, then those same three points of the real-world components must also connect via a conductor.

-By convention, the arrow on a potentiometer symbol indicates the wiper, which typically exists as the middle lug on a real-world potentiometer.

(...and may God have mercy on your soul)

Hello !
I made the crackle not okay, the first vero posted by Soulsonic! This booster rocks, sound way better than the original (to my taste). I only use it in the mimimum gain, just to color my tone, I can't remove it now! I would like to know if we can remove the hiss I got from it. Even at lower setting, it add a bunch of hiss. I'm not an expert as all of you, but can you enlight me with these questions:
-Changing resistor (I use regular carbon,5%, from smallbear) for metal film, 1% will decrease noise?
-Trying other BS170 ?
-Changing cap (I use the smallbear one)?
-Maybe it's just the booster that is like that...?
Thanks.

Almost all hiss comes from the transistor, so changing transistor types may help with the amount of noise. I have built this with a BS250 type and it did seem to have less noise, but to be able to use that type, you will have to modify the polarity of the circuit - because the BS250 is a P-Channel type and the BS170 is N-Channel. Other MOSFET transistor types may work as improved substitutes, but I have not tried them yet, so I do not know which would be a good choice. You can also use a Bipolar transistor in this circuit and it should function. You could try a low-noise type, like an MPSA18.

When it comes to noise from other components; the only resistor that will really have much affect on noise is likely to be the Drain resistor (the 5K1). Using a good quality metal film type with a higher wattage rating - like 1/2 watt or even 1 watt size - may possibly reduce the amount of hiss slightly. The other resistors likely would not affect noise, because the amount of current flowing through them is very small in comparison to that of the Drain resistor. Putting a small value resistor in series with the Source (instead of connecting straight to ground) - something between 47 ohm and 150 ohm - will lower the overall gain very slightly, and may also reduce the hiss a little bit. If you only want to have a mild amount of maximum gain, you could put an even higher resistance there - like 1K, for example - and this should reduce the hiss very much; but that will also dramatically reduce the maximum amount of gain available from the circuit.

dantahoua wrote:Hello !
I made the crackle not okay, the first vero posted by Soulsonic! This booster rocks, sound way better than the original (to my taste). I only use it in the mimimum gain, just to color my tone, I can't remove it now! I would like to know if we can remove the hiss I got from it. Even at lower setting, it add a bunch of hiss. I'm not an expert as all of you, but can you enlight me with these questions:
-Changing resistor (I use regular carbon,5%, from smallbear) for metal film, 1% will decrease noise?
-Trying other BS170 ?
-Changing cap (I use the smallbear one)?
-Maybe it's just the booster that is like that...?
Thanks.

CNO on +18V question here, for Soulsonic or anyone else who wants to play along.

Is it wise to change the 12V Zener diode to a larger size if the CNO/SHO/MOSFET Booster are run at +18V?

I've read some info lying about regarding high-frequency noise-reduction (Comment 607/Jack's Reply 608 in the comment section at http://www.muzique.com/news/amz-mosfet-booster) with the MOSFET Booster running at +18v; Jack suggested increasing the size of the capacitor shunt parallel to the 12V Zener from 47pF to 470pF. (I have not encountered this issue yet, but I thought I'd mention the potential solution...which would be to add 470pF cap parallel to the 12V Zener in the CNO and SHO.)

I know there are others out there successfully running their CNOs/SHOs/MOSFET Boosters at +18V without issue, but I can't find much evidence of issues with that configuration. That tells me that the circuit works at +18V, but it doesn't tell me if the MOSFET-protection Zener is properly sized to handle the increase from +9V to +18V. (Just because the circuit works in its normal-use scenario (no ESD discharge or other voltage spike on the MOSFET input) doesn't mean the edge-case scenario of ESD/voltage spike on MOSFET input protection (12V Zener) will work at +18V.)

I've SPICE modeled the CNO with +18V in a variety of circuits, none of them indicating any gnarly issues with the CNO @ +18V. My inexperience with SPICE has thus far prevented me from modeling the "ESD/voltage spike on MOSFET input" scenario, so if that's possible, I'd gladly accept any guidance in modeling that scenario in PSPICE or NI MultiSim.

If y'all could pitch in an help my understanding here, it would be appreciated. Thanks in advance for any and all assists on this question.

the diode is not to protect from D-S voltage, its for limiting the gate-source voltage. The facts are on the datasheet.

eg. 2n7000:
V D-S: max 60v
V G-S: max 20v

you can run the whole thing at 60v, but you dont want more than 20v at the gate or it'll smoke, thats what the zenner is there for. And, anyway, you wont ever need more that 9v at the gate so the 9 or 12v z-diode is a one fit for the usual mosfets.

note that other mosfets may have different ratings, read the datasheets.

cpm wrote:the diode is not to protect from D-S voltage, its for limiting the gate-source voltage. The facts are on the datasheet.

eg. 2n7000:
V D-S: max 60v
V G-S: max 20v

you can run the whole thing at 60v, but you dont want more than 20v at the gate or it'll smoke, thats what the zenner is there for. And, anyway, you wont ever need more that 9v at the gate so the 9 or 12v z-diode is a one fit for the usual mosfets.

note that other mosfets may have different ratings, read the datasheets.

Thank you very much. Your reply not only answered my question, but also enabled me to answer it myself next time.

I tried to build one of the nocrackle shos, but only very little, almost no sound at all.

voltages on the bs170 from top to bottom (I am using M.C.s Vero layout) are:

4.70V
5.3 V
8.2 Volts

what to check?

No shorts as far as I can tell - I multimetered the whole board a couple of times.
Bypass is ok, Led goes on...



HALP!

I still have no idea what was going on with the first build - I threw a second build together, same layout, different ("mojo") parts.
It worked from the getgo. BUT I there is something strange going on:

When I have the boost volume maxed, and guitar volume maxed everything is fine. As soon as I turn down the GUITAR volume, I get a weird oscillator noise with no guitar signal coming through at all. that oscillating noise is very prominent between 8-2 on the GUITAR volume (when CNO-SHO Volume maxed), and is gone at 10-9 and also missing from 2-1.

What did I mess up this time...?!

The Source pin of the MOSFET should read 0v because it is supposed to connect directly to ground. Make sure all the strips on the vero are cut correctly. It sounds like the Source isn't making the connection to ground like it should.

hm... I wonder if I missed any cuts? I count three in total.

Guess I will just build another

check for continuity between that pin and ground. You should be able to fix that issue without building a new one from scratch.

dear mr soulsonic.

thanks for bringing a noob on the right track. I will do just as you said and report back later this week. thanks again !

so is C3 the same kind of cap (bipolar) as C2 (and which cap brand should I use if I am ordering from small bear)? And if I was going to wire a master in place of r4 would I use just a plain jane 100k linear taper pot? And if I did wire the master how would I wire the pot? bridge terminals 1 and 2 and wire them to one side and 3 to the other side where the resistor would go?

(sorry for the noob questions)

I built this up on breadboard and it is sounding really weak, especially compared to a sho. I think I might have gotten some parts wrong, can somebody go over my bill of materials and tell me if anything seems wrong. I put a * next to items I made substitutions.

resistors
r1 5k1
r2 2M2
r3 2M2
r4 100k

Caps
c1 100 nF (code 104 blue ceramic cap)
c2 * 10uF tantalum capacitor (this part is not bipolar, but I connected the positive end to 5k1)
c3 47uF - I am using 47MFD 50V hi-temp electrolytic capacitor

Diodes
d1 * I am using NTE578 r-Schottky, 1A 90V
d2 1N5242

transistors
q1 BS170 (NTE 490)

pots
p1 * 1M linear

I thought my pot was the problem, so I tried several different resistors in place of the pot the 470k got a little bit more volume out, but it was also more clipped.