Anderton's Tube Sound Fuzz... Help?

[jmth]

Hi, this is my first DIY pedal project, but I know the basics because I have made some PCB's and projects before, I made it following all the instructions here:

http://www.tonepad.com/project.asp?id=65
Including 100K/10M switch

It was very easy to do, but when I tested it with the guitar, all it sounds is a chirp: "PIIIIIIIIIII" and when I touch the ground conections it makes some background noise, but when I touch de volume pot, it can do "piii", background noise, or no sound, sometimes I can hear the guitar on background. I first thought it was because of impedance but I "calculated" it has several millions ohms... ¿Some ideas please? Someone told me to include an operational amplifier whithout gain but I don't think it's the solution. Thank you!  

[Mark Hammer]

There are two kinds of CD4049 the 4049UBE (unbuffered) and the 4049B (buffered).  Although they have identical pinouts, you MUST use the UBE version or it will not work.  Unfortunately, the document at the Tonepad site does not mention that dstinction.

Is it possible that is what's gumming up the works?

[Canucker]

I built mine with a chip marked HD14049UBP  NOR UBE.....and it kinda works....fine when I'm playing but if I'm not playing theres extra noise.

[Mark Hammer]

Slightly different suffix, but you are using the correct unbuffered type.  If you have built it on perf or vero, rather than a "vetted" PCB layout, keep in mind that the inputs to the unused sections have to be tied together to V+ if you wish to avoid "misbehaviour".

[jmth]

Sorry I didn't mention it... I'm using the 4049UBE so that's not the problem.
The unused pins are as the schematics says... nc, entrance solded to +9, not the problem too. 

[lonewolf]

if you socketed the IC it will be easy to check continuity to find problems..but that 4049 is static sensitive so you want to be careful when probing..I have built every hex inverter circuit there is (almost) and havent had a problem with static but I always use sockets..make sure everything is oriented properly,etc and there are no opens or shorts..did you use a pcb or perf,etc?

[Nasse]

You used battery or mains powered supply???

[jmth]

I probed the IC socket when I solded it, and all the tracks after etching (PCB). Electrolitic capacitors are oriented properly and I checked the IC orientation and inputs/outputs, I will check opens, shorts, voltage, intensity,... tomorrow and do a list, but continuity is ok everywhere. What do you mean with "static sensitive"? I oriented resistances and other capacitors too in the order the symbols are read... I know it's useless 

I'm using a 9V battery with a socket I bought for connecting it easily...
Thank you for your help 

[psychedelicfish]

but that 4049 is static sensitive so you want to be careful when probing

Actually, according to a data sheet I saw somewhere, the 4049 has inbuilt static protection protection.

Anyway, to answer Jmth's question about static discharge, over time, your body gets statically charged from things like clothes rubbing against your body when you move, just like when you rub a balloon against a woolen garment and then use the balloon to make your hair stick up. When you touch a conductive object, this charge in your body is quickly released into the object (this is normally too small to feel, but you can feel it if there is enough charge, e.g. when you wear something fluffy for some time without touching something conductive). This is harmful to some electronic devices, particularly ones involving MOSFETs and CMOS. The MOS in those stands for Metal Oxide Semiconductor, and metal oxides will break down and the device will stop working if even a relatively small amount of electricity is rapidly discharged through it. The CD4049 is a CMOS device, and so can be damaged with static discharge from your body.

[psychedelicfish]

Also, what capacitors do you have from the positive rail to gnd? I would suggest increasing the value or having more capacitors from positive to earth, as the CD4049 is a sensitive little b**** and I often find that it screams at me if I have too much power supply ripple

[jmth]

thank you, I didn't know that  

I have 1 capacitor (electrolytic 100uF) I can replace it with some of 250 or 500 uF I have...

I have probed all connections, voltages etc... Just two things:

- I have connected the LED in serie with +9Vin so V is here 9.4 (battery voltage) and 7.4 on +9Vin, should I connect it parallel?
- I saw in some true bypass schematics that the GND of the jacks in and out are connected to battery ground (I solded it to GND on circuit), it's really ok?

Practical probe: I solded a new pot, and the chirp has been reduced, but when I change the switch to 10M or touch ground it returns, the guitar sounds with fuzz on background and distorted interferences, sometimes when I move it all it sounds is background noise and LED turns off instantly. Clean sound as good as ever.

New edit: when I touch the Jack in ground while I touch the guitar it sounds no chirp but the guitar is too much distorted or sounds well, but  when I silence the guitar it sounds the chirp again

[snap]

- I have connected the LED in serie with +9Vin so V is here 9.4 (battery voltage) and 7.4 on +9Vin

there you go.
and where did you connect the positive pole of the 100µF to? Pin1 of the IC, or +9Vin?

[lonewolf]

I was going to tell you to check the build reports at tonepad but none of them mention any problems with this circuit so...
If everything you check seems correct (no shorts/opens/reversed/backwards,etc) and you socketed the IC then you could swap that..they are not expensive at mammoth,etc..I have bought the NTE4049 and they have a red warning sticker on them saying to handle only at static sensitive workstations..I just touch something grounded or use a wrist ground strap like you use when working on computers..if you are using a battery then you wont have problems with P.S. ripple...

[jmth]

the 100uF (now temporaly 450...) capacitor just goes from all the +9 IC inputs to ground, so it's really connected to a resistance that comes from battery, to ground. And it's connected with pin 1 too.

I have another CD4049UBE too, If nothing seems to work, i will replace it...

[lonewolf]

that cap is not your problem...If you search tube sound fuzz in this forum you will find a lot of threads about this circuit..are you using the led as a status indicator? 

[jmth]

yes, the LED is just an indicator...
Changes with the new cap: now the guitar is ground, the volume turns down (with the chirp) when I touch strings, and up when not.
I'm thinking again that's impedance because with the pots at max resistance, the chirp volume turns up, and when they are at minimum it sounds better.

I have been searching for the circuit here but didn't read anything useful.

[Mark Hammer]

The Way Huge Red Llama is based on the Anderton circuit, so you may be able to find some troubleshooting ideas by looking for that.

[lonewolf]

have you checked resistors to make sure you didnt make a mistake(100 ohms instead of 100k)..you should check the resistors with a meter before you install them..I dont rely on color codes and what is on the package.. I double check with a meter..and look closely with a magnafier to make sure you didnt miss a bridge or sloppy solder joint

[LucifersTrip]

just breadboarded it and it worked right off. if it helps, I have ~ 3.3V on pin 9, 10, 14, 15

a couple negatives: it sounds like the typical IC based distortion, with some sizzle/fizzyness at higher gains...and I don't know what you call it, but after about 75-80% on the volume, the circuit sounds "overdriven". the standard background hum disappears and turns into mild oscillation with fizzy attack/decay and a load of overtones appear, similar to an octave...similar to what happens in a SHO in the last 2%.

[jmth]

All resistances and caps checked.
I have ~2.6V in those pins.