Build Your Own Clone Message Board

Hey Everybody,
It sure is fun putting them together, I wish I could have fun playing with them, lol.

First I'll describe the problem. I've read a bunch of posts that touch on it, but don't have quite the same problems. Bypass and LED both work. When I get signal it's super fizzy, like on top of the fuzz. And if I barely pluck the strings I get no sound at all, I don't have to hit them overly hard to get a signal or sound but it's obvious there's something up with the amount of input I'm getting. Volume-wise it seems a bit low compared to the effect being off. If the lower eyelet in R5 was damaged, is it possible that some signal is getting through but not the entire amount? And, from what I can tell, the pots and rotary seem to be working. If there are better pictures that anyone would like to see please let me know.

What I've done so far is check the switch according to the Troubleshooting post, and if 0 ohms means continuity then the switch seems to be OK which is pointing at the effect circuit.

The Transistors tested at:
Q1: 2.2
Q2: 2.0
Q3: 4.0
Q4: 4.1

Thanks for any help, I'm running out of hair scratching my head trying to figure these things out!
Jon

Pictures are below:

Your soldering looks suspect. Many of the joints look cold and/or solder starved.

One big positive...those are great pictures. All ya'll out there who want help, take a look at these pics. They are clear, in focus and the right size.
Sorry I don't know about this circuit to help, but there looks to be a lifted joint on the back of the board in the 6th picture by the rotary switch.
-P

Hey, thanks for the replies.

I've actually reheated the joints 3 times, now 4 counting tonight. I'm using the Weller 25w with .032" 60/40 solder. Below are more pics (as close as I could get). They aren't as in good focus but I was trying to show the gleam in joints. The joints look shiny and probably about 80-90% are actually coming through the other side in a nice Kiss shape, but smaller. Most are angled looking because of bending the wire on the soldering side of the PCB. The Transistor readings are the same as before. I don't really know what else to check unless there are particular parts on the PCB to check. I'm afraid I've reheated everything so much that an overheated component could be a problem. And I don't know what the "max" is for reheating things without burning them up.

Thanks again in advance for any insight!
Jon

Your soldering still looks cold. A quality solder joint should never look like a spike.

The problem with re-flowing solder joints several times over is that you - either do it without adding further solder and hope that the amount of solder from the first attempt is enough to make a good joint and the excess flux from the first attempt is enough to break down any surface oxides and to reduce the surface tension of the solder allowing it to flow out properly. Or - you add solder (which you should of course do if the original looks solder starved, but this is often not the case) principally to get some more fresh flux onto the joint to help it flow out. Trouble is, beyond a certain point adding more solder+flux can result in overloading the joint. If you then are a bit slow in removing the iron you will get an ice cream cone effect point or spike as the excess solder follows the iron as it moves away. Once that happens if you want a good looking joint the only remedy is to remove most of the solder (I prefer to use a solder sucker for this - de-soldering braid never really worked for me) and then redo the joint with fresh solder.

Anyway - from what I can see of the Beaver circuit/s it has 4 transistor stages which are all AC coupled so the DC conditions of each stage do not depend on the other stages. As far as I can see the first and last transistor stage are straight amplification stages not intended to produce distortion while stages 2 and 3 have clipping diodes. Other than that apart from some slight changes in resistor values the four stages look very similar so I would expect the DC conditions to be similar. You gave some voltages for the 4 transistors - I'm assuming these are voltages measured between ground and the collector of each transistor? It is often hard to tell with fuzz circuits but I think the 4 transistor stages should bias roughly the same with the collector voltage sitting at roughly half the supply voltage. So the voltages for Q1 and Q2 look off to me. It would help to know exactly which version you built and if we knew what the typical DC conditions are in a fully functioning pedal.

If for example the first transistor stage was incorrectly biased it would not smoothly amplify the input signal, but would likely have a threshold, requiring a certain level of input signal before it would pass any signal to the next stage and adding its own hard clipped distortion to the sound.

Unfortunately, contrary to the instructions, you have soldered the transistors in, so you can't easily try swapping them around to see if the DC conditions follow the transistor.

Those Q1 and Q2 collector voltages look very low to me--I don't have a Ram's Head LB handy to check, but I'd really expect them to be up in the 4 - 6V range. I don't see any component placement issues, so I would agree that the likely cause is a cold solder joint or two. I'd suggest going through the build and carefully inspect all of the soldering in the first two transistor gain stages--you can see them color-coded in THIS POST.

You may need to re-do a couple of the joints that look particularly blobby or "spikey". Also look closely for any evidence of solder "bridging" between adjacent eyelets that are not already connected with a board trace, as well as solder splash that could cause shorting. Holding up the PCB with a bright light source behind it is a useful technique for spotting solder where it shouldn't be.

Thanks again,
I'll keep checking it out.

As for the soldered in transistors, the instructions clearly state that the kit does not come with sockets anymore and to solder the transistors directly to the board. It's the Ram's Head version too if that matters.

Thanks!
Jon

If your inspection of the pedal doesn't turn anything up, you may need to go the route of buying or building yourself a signal tester, so that you can trace the signal through the effect circuit and determine where it's dropping out. But we'll cross that bridge when we come to it....

Thanks, that is on my "next purchase" list if I end up buying another one. I'll run through it again tonight, darn work is getting in the way of my hobbies!

Thanks!
Jon

Sorry about the sockets comment - I missed the RED notes about sockets no longer included. BYOC instructions always lay a lot of stress on using sockets so I assumed they were included.

In the Rams Head version apart from the clipping diodes, stage 1 and stage 2 are very similar except in stage 1 the lower base bias resistor R3 is 43K. In stage 2 the lower bias resistor R11 is 100K.
And stage 3 is very similar to stage 2 except for the collector load R19 of 15K.

Given those bias resistor values I would have expected the collector voltage of Q1 to be higher than for Q2 since the base bias is lower, which it is but not by much. In fact with those values if the collector of Q1 were at even half the supply (4.5v) then the base would only be at about 0.38V which seems very low for a silicon transistor. To start with I would focus on that first stage.

By the way, like a lot of other Fuzz pedals, this circuit has a very low input impedance of only around 80K.

No problem about the sockets!

I've been messing with it for the last couple hours. Resoldered and/or reheated the first stage. Q1 is about 3.2 and Q2 is 3.0. But still the same original problems persist. I've also noticed that the Sustain knob controls some volume too, which could have been happening all along. I read another post about it but I don't think it ever got resolved.

Thanks again for any ideas, I'm at a loss.

Jon

Another quick question... Are the solder joints for the little orange clear things with the black stripes that are super close together supposed to be touching on the solder side of the PCB? On the component side I think they are separated but on the solder side they have got soldered together.

Thanks again for all the help!

Jon

Those would be the back to back clipping diodes around stages 2 and 3. Yes the black stripe end of each is supposed to be connected the the clear end of the other. These are the bits that actually give you the fuzz. That said good soldering technique should result in the wire ends of these components being individually soldered to their respective mounting pads and the required connection between them being made by the copper PCB track. Applying too much solder so these two close together connections form a solder bridge won't affect circuit function, it's just bad technique.

By the way I can understand why it is often recommended on this forum that new builders having problems with their build working should go over and re-heat all their solder joints, with the hope this will fix any bad joints, but it is a very scatter gun approach. It seems to me that in lot of cases the joint quality is actually made worse, with extra solder, flux and general dirt building up on the back of the PCB. Also, every time joints are re-heated is adding further heat stress to components that would normally only be soldered once.

All the four transistor stages in the Beaver amplify the signal from the guitar, but those two stages have back to back diodes in their feedback loops. As a result, for small signals their gain is relatively high, then, as the input signal swing increases, the diodes conduct and reduce the gain. When this happens the peaks of the input signal get limited and flattened out. This is intentional distortion or non-linearity.

Interesting that the collector voltage of stages 1 & 2 should have increased from 2.2 and 2 to 3.2 and 3. Have you switched to using a new battery?

Ok, lets take this step by step.

We need to know exactly what supply voltage we're working with, so test the battery and/or power supply and let us know.

At 3.2 and 3.0, respectively, Q1 and Q2 seem low. Not bad, but it could certainly be a cause of the "fizziness". I generally like to see my collectors at about 4.0-4.5 volts, if my power supply is pushing 9.0 volts. Usually I like to see Q4 with a slightly higher voltage, maybe 0.3-0.5 volts higher, than Q1-Q3. I am OK with your Q3 and Q4 for now, but recheck them and give the full voltage reading of all the transistors.

Also, give us the Base and Emitter readings, too. May help us figure out if there is a transistor issue.

Hi,
The battery checks out at 8.8.

I'm assuming the Base and Emitter are the other two connections for the transistors and are tested the exact same way as the Collector. If so the readings are below.

Q1:
C=2.9
E=Infinity Needle doesn't move at all
B=1k? Problem is is that this is the last mark before infinity, so needle BARELY moves.

Q2:
C=2.7
E=Infinity Needle doesn't move at all
B=1k? Problem is is that this is the last mark before infinity, so needle BARELY moves.
Q3:
C=6.5
E=Infinity Needle doesn't move at all
B=1k? Problem is is that this is the last mark before infinity, so needle BARELY moves.

Q4:
C=5.5
E=Infinity Needle doesn't move at all
B=1k? Problem is is that this is the last mark before infinity, so needle BARELY moves.

I think I messed with it after my last post last night, that's what I'm thinking is accountable for the slightly different readings from before. I check it multiple times to make I'm getting a consistent reading too.

Thanks again!
Jon

Did you get these recent with guitar cables pulled into the input Jack? If not, recheck them with the cable in.

Infinity and 1K ?? So you are using an analogue meter set for reading DC voltage on whatever range you have that is more than 9V full scale?

Infinity and 1K sound more to me as if the needle on your multimeter is hard to the right and you have it set for a resistance reading which is not what is needed.

First,
Thanks again for all you guys taking time out of your day. I'm obviously ignorant of a lot (most?) of this stuff, but learning as quickly as I can.

The tests have all been done with a cable hooked up to the input jack and the pedal ON. I don't have it in the box yet, but I do have the ground wire hooked up from the output jack. I had it in the box when I first tested it and have had the same results.

Here is the tester I'm using. In the pics it is set on the setting I've been using to read the Transistors. I really don't know much about this meter (or any other meter), a friend gave it to me a few years ago. In the second photo you can see the end of the scale where I'm getting the Emitter and Base readings. If I need to set the meter differently, please let me know, and possibly which scale to be reading. The 3rd picture shows where the readings are for each of the 4 transistors (Collector only).

Thanks!
Jon

Ok, let see start off by setting the meter to the other side (DCV 10), then retake your measurements. Currently you are measuring Milliamps not voltage.
-P

Doh!

Ok, here's a pic of the readings from the Collectors. The Emitter and Base readings were the same as before, basically pegged or almost pegged to the left side of the scale.

Thanks!
Jon

OH MAN AM I A DUMBA**!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Since Patrick told me what to put the settings on to measure correctly, I measured the battery, (which has never been used but obviously loses a lot of power sitting in a guitar case!) and then measured a brand spanking new one bought recently. Go figure the damn thing works!

I wouldn't doubt if it's the same dang thing with my Phase Royal. Still in my (bad) defense - the bad battery had never been plugged in. That's still comparable to "Is the unit plugged in" though huh?

Sorry to have wasted all you guys time, but I'm glad it finally worked out and I did learn a lot just messing with it.

Time to go play!

THANKS A MILLION FOR ALL THE HELP TOO, WITHOUT IT I NEVER WOULD HAVE THOUGHT TO RECHECK THAT BATTERY!

Jon

Great - glad to hear it works.

A brand new battery should measure perhaps as much as 9.5 volts (alkaline batteries usually measure a bit lower) with your meter. Once a battery gets down to 8 volts or less it may or may not still have some life left in it. What you really need to do is measure battery voltage with a load such as it would have when plugged in to a pedal and the pedal being switched on. The pedal in that case would be the load. How much the pedal loads the battery varies from pedal to pedal. As a very rough rule of thumb the more complex the pedal with the more parts it has the greater the load it will place on the battery.

Batteries generate electrical power from a chemical reaction and the current flowing through the circuit also has to flow through the battery. As batteries get near to the end of their life the chemicals inside will have almost all completed their reactions and the internal resistance of the battery rises. So you can have one battery that reads a bit low on the meter but still has some useful life left and another battery that reads much the same but has a much higher internal resistance. A meter usually wont load batteries much but as soon as you load that second battery by, for example, plugging it in to a pedal the output voltage will nose dive. Its the increase in internal resistance combined with a low terminal voltage that is the reason behind some people saying that some pedals sound better with an old battery. A well designed pedal wont be as affected by the state of the battery.

Modern batteries normally have quite a good shelf life but although the chemical reaction inside slows when they aren't used, it never stops completely. It does depend how the battery is stored. If you keep them in a cool (but not freezing) reasonably dry place they will keep for longer. Typical storage life is no more than 1 year. You can use rechargeable batteries but they often have a lower terminal voltage than the non-rechargables and a lower energy density so they don't last as long in use.