Help with Fuzz Face, Newbie (Photos)

[Plork]

I am breadboarding an NPN Silicon fuzzface, using the breadboard kit sold form Small Bear. This is my first circuit build, though I do have some experience soldering. Other than that I am a novice. The transistors are 2n222a, and I've checked the pinout a bunch of times, so I am fairly confident they are wired correctly in the circuit.

To the best of my knowledge the circuit board is wired up correctly, I've gone over it a dozen times, but it does not function. You can hear noises when the pots are turned, and unplugging from either jack creates noise. I discovered unplugging the jacks that guitar signal actually passes through when partially unplugged and the tip of the cable is touching the sleeve of the jack -but there is no fuzz effect. I know I need to use my multimeter (I have an analog one, I'll post a picture) to test different parts of the circuit, but I'm  uncertain about what setting to use and what math I need to do...

Unless I fried something, I think the problem may have to do with the way the pots and/or jacks are wired. Do both pots share a jumper on their first lug, that then travels from the volume pot to ground? Or is it fine to just wire them individually to ground? I have much to learn.

Breadboard:


[url=https://flic.kr/p/2a5xwnX]

Meter:
[url=https://flic.kr/p/2a5xwSp]

Thanks for your help.

[smallbearelec]

I don't see any mistakes in the board connections. The pots look to be wired OK. Are you Sure that you have correctly ID'd tip and sleeve of the jacks? Orient the jacks the same way that they appear in the How-To:

http://diy.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm

with the Chamfer (flatted edge) facing you.  Ensure that tip and sleeve go where they are supposed to. It's in the nature of these builds that one small thing wrong means that nothing works; we'll find it and get you going.

[Plork]

Thanks for the link, I hadn't seen that.

So which setting should I use on them multimeter to test the voltages of the transistors?

[Plork]

So it turned out to be the jack like the above poster mentioned. Small bear included a stereo jack in the kit and I soldered the output to the wrong lug. Thanks again for the help!

[bluebunny]

Welcome, Plork!  (Great handle, btw.  )  Glad to see you got it sorted.

So which setting should I use on them multimeter to test the voltages of the transistors?

There's no possibility of anything higher than your battery voltage (about 9V) so the "DCV 10" setting - just past noon - would be the one to use.  Put the black lead on a ground point and poke around with the red one.  But seriously, get Steve to sell you a DMM (digital multimeter) - you'll find things so much easier.  Cute old meter, though.    I still have an old Radio Shack meter hiding somewhere in the house.  Must dig it out...

[BetterOffShred]

So it turned out to be the jack like the above poster mentioned. Small bear included a stereo jack in the kit and I soldered the output to the wrong lug. Thanks again for the help!

Steve is legit.  He called me once to help me troubleshoot my tremulous bear..     what a G

Glad you got it working!

[smallbearelec]

Small bear included a stereo jack in the kit and I soldered the output to the wrong lug.

You'll use the ring contact of the stereo jack when you commit to a soldered build and want the power to the board to be turned off when your guitar is unplugged. Now that you have the basic circuit working, give your attention to cleaning up the tone and tweaking the bias as I describe. When you're happy with that, you can think about how you want to package your FF.

Regards
SD

[Plork]

You'll use the ring contact of the stereo jack when you commit to a soldered build and want the power to the board to be turned off when your guitar is unplugged.

Ok, that's good to know, thanks.

I am now in phase 2 of this project, and a bit stuck. I also bought a pair of PNP germanium transistors and most of the parts I will need to put the circuit in an enclosure. The transistors are Japanese, a 2SB77 in Q1 and a B175 in Q2.

I used the resistors included with the transistor pair. I switched the leads coming from the battery to supply -9v, and switched the polarity of the 2 electrolytic caps. I am pretty sure I have the pinout correct, at least for the 2SB77. I admit I'm having trouble finding the pinout for the B175 transistor. I think I read somewhere that it has the same pinout as a TO-1?



[url=https://flic.kr/p/28JpHdo]

[smallbearelec]

Both of those devices are in the TO-1 case, and they have the same pinout. Check out the pics of the devices shown in the How-To. Looking at the bottom, if you orient the leads so that the vertex of the triangle points down, the Collector will be on your left.

[Plork]

Both of those devices are in the TO-1 case, and they have the same pinout. Check out the pics of the devices shown in the How-To. Looking at the bottom, if you orient the leads so that the vertex of the triangle points down, the Collector will be on your left.

Ok, well then that isn't my problem. I have the transistors oriented correctly. It doesn't appear any kind of signal is passing through, when I unplug the input jack the amp makes no noise.

[Lew-Dawg]

Great thread...Can't wait for more.

So you added Germanium clipping diodes of your choice? very slick!

How much were they? 

Lewis

[smallbearelec]

I have the transistors oriented correctly.

OK. Back up a second. The circuit worked previously with the silicon devices and their associated bias resistors. You changed resistors to accomodate germanium And changed the power, right? That's a lot of changes, so it's possible that a mistake krept in. Triple-check your connections. Remember: One small thing wrong means nothing works.

[thermionix]

I can't tell for sure, but I think your input cap is going to collector instead of base.

[Plork]

I can't tell for sure, but I think your input cap is going to collector instead of base.
[/quote]

You're correct, I fixed that and it also turned out that I did have the transistors oriented incorrectly. Hopefully I didn't damage them... It sounds pretty good so I think they're okay. This is the first time I've played a germanium FF so I don't have a strong reference point. I ran it into my Catalinbread Echorec and it instantly took me to a happy place.

The plan is to try out some different values in the circuit and then box it up. I'll post back here as I hit roadblocks.

[Plork]

Great thread...Can't wait for more.

So you added Germanium clipping diodes of your choice? very slick!

How much were they? 

Lewis

Thanks Lewis! The transistors were about $10, and they include the 4 resistors.

[thermionix]

...it also turned out that I did have the transistors oriented incorrectly. Hopefully I didn't damage them... It sounds pretty good so I think they're okay. This is the first time I've played a germanium FF so I don't have a strong reference point. I ran it into my Catalinbread Echorec and it instantly took me to a happy place.

Every time I've hooked up transistors incorrectly they've survived.  If you're in a happy place that's a good sign.  Fuzz Faces contain a range of good sounds if you fiddle with the volume, tone, and pickup selector on your guitar.

[PRR]

> Every time I've hooked up transistors incorrectly they've survived.

At 9V, with >1K resistors in series with *any* path through the transistor, you are in nearly no risk of burning a transistor.

In Power Amplifiers, or when hacking thoughtlessly, it is possible to get a transistor turned-ON with full 9V across it and no series resistance. Transistors will try to conduct infinite current. This may not end well.

A proper typical FuzzFace has two current paths from the 9V. One is 33K and one is 6.8+K. Max transistor current (any which way) is 1.3mA;max dissipation is 3mW (0.003W). These values may not work well, but they won't melt the transistors.

Get into power amps, with <1 Ohm emitter resistors and nominal 8r load which often ends up shorted, all on say 50V, you have 100 Amperes and 5,000 Watts potentially available. You can blow-up $7 transistors all day long.

[thermionix]

Power amps have tubes, not transistors.  But yes, damn sure better hook them up correctly every time.

My very first tube amp was one of those Paul Rivera-bastardized Fenders from the early 80s.  The day I got it I pulled one of the 6L6s out to have a look-see.  The guide key had been broken off of the base, but I didn't even know there was supposed to be one.  So how should I put the tube back in?  Well, I think I remember it was oriented this way.  Poof!  Magic smoke from the screen resistor.  But I didn't know what a screen resistor was.  I replaced it with some kind of resistor from Radio Shack.  The amp ran for several more years, but probably not correctly.  No recollection of how/when/where I got rid of that thing.

[Plork]

Update: The circuit is still on the breadboard.

I need some help with the next step. Are there any good youtube tutorials about working with this type of circuit board? I can solder I just need to figure out how to lay out the components on this board.

[willienillie]

I would say first thing to do is figure out how and where you're going to mount your board.  The placement of the jacks in that enclosure might limit you to a fairly small area either "north" or "south" of the jacks.  But not to worry, the FF is a simple circuit, and can be built on a piece of perfboard the size of a postage stamp.  You can stand the resistors up and mount them in two adjacent holes to save space, if needed.

I don't know of any tutorials, but you can use graph paper with each + to represent a hole in the board.  Mark off an area of graph paper the size your board will be cut down to (i.e. 8 holes by 12 holes or whatever).  Then start placing the components in the board without soldering to see how they fit.  A good general rule for layout is to try to make it similar to the schematic, usually with signal flow from one side to the other.  Quadruple check every connection against the schematic before you start soldering.  Then just bend the leads at right angles on the copper side to reach the next connection, solder in place.

Look around for here pics of other perfboard builds, particularly the underside, and it might start to make sense.