Sustain and Saturation for Distortion Pedal

[ElectricDruid]

I doubt if the unity-gain amp will make any difference compared with the non-inverting one. They're basically the same thing. I only pointed you at the unity-gain one because it's marginally simpler for a quick test, but if you've made the other one work, that's cool. It's a very useful circuit.

The only difference is the gain. You've got 50K/10K+1 = x6 gain on that first stage. What's the signal level going in?

Tom

[Yggda]

What's the signal level going in?

I don`t have any equipment to measure this one. It is connected to the guitar output. Sources say that RMS voltage is about 100mV for Epiphone LesPaul Secial II.

[Yggda]

Can it caused by 9V battery?

When a common power supply is used for several stages of amplification, the supply voltage may vary with the changing current in the output stage

or ...where can I have "parasitic feedback"?

Thanks

[ElectricDruid]

Can it caused by 9V battery?

Unlikely. Not impossible.

When a common power supply is used for several stages of amplification, the supply voltage may vary with the changing current in the output stage

I don't know which article that's from, but it sounds more like they're talking about high-power output stages pulling the supply voltage down. This was common in Fender guitar amps and became a desirable "character" rather than a flaw. In those amps, it's known as "power sag".
Anyway, it's not something you'd have to worry about in a pedal.

The supply voltage dropping is usually caused by a short circuit, or a very low resistance across the power rails. In either situation, you need to find the cause rather than "fix" it by providing a high-current supply.

Tom

[Yggda]

Hi,

On the scheme there is a ground connection nearby "negative" battery output. However, in the real circuit the ground is the negative battery connection.


I just think that the potential of battery is floating, while the amplifier ground is const 0 ---> that cause the "waving".

Can that be true? How to connect the pedal to the ground if it is not in the metal box? 

Thank you!

[Yggda]

Hi,

I tried a lot of different things with grounding - the result was the same.  After, I tried to eliminate circuit parts to detect the source of waves - and found that even with the straight guitar connection to the amp - the sound was waving 

[duck_arse]

was it waving goodbye?

so now you need to find out what is waving, and you have only three choices, the axe, the amp, or the cord betweeen.

[wilrecar77]

In my experience, a guitar with the pickups too close to the strings can cause a "waving" sound like that. Try lowering your pickups.