Tonebender Noise

[Schappy]

I justed built a Tonebender MK2 on perf and everything is fine except that I get a lot of noise at higher gain levels.

Is this something inherent in this circuit or should I be looking somewhere else?

[Brymus]

Is it Ge or Si ?
I have made one and it has almost zero noise with both Ge or Si trannies in it.
In fact it is one of the quietest pedals I have either store bought or DIY.

[Schappy]

Its Germanium

Its starts to get noisy at about 3 o clock.

[azrael]

Did you use metal film resistors? What kind of gains/leakage did you have? is it in an enclosure?

[Schappy]

Would using a trimmer in place of the 8.2K resistor help?

[azrael]

Well, that would help bias it, could get better sounds...What's the Voltage at Q3's collector?

And are you using metal film resistors? They're quieter than carbon...

[glenn.b]

What sorta noise do you have?  Be descriptive...when you unplug the guitar from the cable, do you still have noise?  If the sound goes away, something about the chain leading to and including the guitar are possible culprits.  MarkII's are hi-gain stompboxes, and if you have hi gain pickups, you might have alot of noise!  Beside that all, I do have some general ideas...I have an MKII as well, along with a couple of treble boosters, so I have an idea what your talking about-both are Ge...  What are you doing to power your MKII?   I have found that on those Germanium trannie effects, they are very reactive to power noise, so they are some of a very small group of effects that do not get plugged in to a wall wart.  Normal household AC is really filthy, nasty, dirty power, are you can hear it through Hi-gain effects...Another thing that I found is that RangeMasters, MKII's, and such do not like fluorescent lights-same it true for ceiling fans with adjustable (Variable) speeds...houses are noisy places.  Please, feel free hit me up, but give us more info! 

[Schappy]

The noise is only present at the higher gain settings of the gain pot. It is the hum you get in a high gain circuit.

Ive read in another thread that putting resistance between Q1 and ground can tame the gain.

What resistance should I put there?

[azrael]

well, why would you need to? what are the gains of the germaniums?

you're hardly answering any of the questions that would let us help you.

[Schappy]

Not sure what else I can tell you.

Noise at higher gain settings.

Dont know the gain of the transistors but got a matched set through small bear.

Using wall wart for power.

[Solidhex]

There's an easy way to test whether or not changing the 100k on the base of Q1 will help. Just turn the knobs all the way up, take a 10k resistor and touch one end to the junction of Q1's base and the input cap, touch the other to ground. Depending on the gain of the transistors you should still have plenty of fuzz. I think it gives a better range to the attack knob if your transistors are biased properly.
  This is a high gain circuit though and noisy transistors can be a problem here. Its always good to test your transistors before soldering and also to make sure you don't keep the solder iron on them too long.

--Brad

[Schappy]

Unfortunately my multimeter doent measure HFE. I need to get a new one.

It definitely sounds like Im getting too much gain out of the circuit.

[azrael]

Well, that would help bias it, could get better sounds...What's the Voltage at Q3's collector?

And are you using metal film resistors? They're quieter than carbon...

There's two questions you could've answered.   

In fact, voltages from all transistors would be great.

[Schappy]

I didnt use metal film resistors.

I will post voltages a litter later.

[Schappy]

Im getting 8.9V at Q3's collector.

Should I put a trimpot in place of the 8.2k resistor or does the problem lie elsewhere?

[Schappy]

scratch that. That reading was wrong. In the process I lost a leg of a transistor.

[azrael]

:sad:
how did that happen?

[Schappy]

I tried to reseat the transisitors in their sockets so I could get a good voltage reading.

I originally had the transistors pushed all the way down on the socket.

What is the best way to socket germanium transistors?

The legs are quite flimsy.
Should I forgo the sockets?

Anyways Im going to order some more transisitors from small bear.

[G]

Not necessarily what your problem is here, but try swapping your transistors around.  I found that putting the leakiest one in a certain position completely got rid of some terrible noise.

I'm racking my brains but I just can't remember which one it was.  Probably either Q1 or Q2.    I'm leaning towards Q1 but it was a while ago.

Some help here, eh?    Try changing them around when you get new ones if you have the same problem and you're using sockets.  You may get a pleasant surprise, I did.

[azrael]

I still use sockets with Ge trannies. Just treat them gingerly, don't trim legs until you're sure you're done.