1st attempt at OpAmp..

[Cvp1969]

I am learning OpAmps now. My first attempt is a Dan Armstrong Blue Clipper. I really think that I have it wired correct on the breadboard. I’m using an RC4458 IC chip. When I switch it on- I get a beating hum and gated sound. When I switch the power on the chip to 18v- it works fine. I tried a tl072 and the same thing happens… thoughts?

(I tried to post videos but they won’t take. Just trust me- 18v works.)

 

[jwin615]

R1/R2 values look off
Sub a 20k for R2 and try again.

 

[Cvp1969]

I’ll try this.. thanks.

I pulled another schematic and R1 is 200 ohms.

 

[Cvp1969]

R1/R2 values look off
Sub a 20k for R2 and try again.

Changed R1 to 220k and it works.. schematic was wrong

 

[drew.spriggs]

Changed R1 to 220k and it works.. schematic was wrong

Op-amps get biased to roughly half the supply rail - so you want the voltage divider to have two equal(ish) resistors for R1/R2 so the middle of these will be ~4.5v.

 

[jwin615]

Unless you want asym opamp Distortion, which is possibly the goal (or it's a typo). But, a 1/10 voltage divider seem really extreme.

 

[spi]

LOL "fairly unremarkable op-amp booster" is not selling it for me.

I see many schematics are using 200K for R1.

Try a dist+, it's not much different component-wise, but people actually like it.

 

[Cvp1969]

LOL "fairly unremarkable op-amp booster" is not selling it for me.

I see many schematics are using 200K for R1.

Try a dist+, it's not much different component-wise, but people actually like it.

I actually dig this circuit now its working and I’m doing all the Dan Armstrong circuits.

Theees quite a few mods you can do to this circuit.

 

[BuddytheReow]

To learn the basics of opamps try breadboarding a mini muffin fuzz (inverting) and a Dist + (non inverting). There are breadboard tutorials in the Test Kitchen here to guide you in the right direction.

 

[Cvp1969]

To learn the basics of opamps try breadboarding a mini muffin fuzz (inverting) and a Dist + (non inverting). There are breadboard tutorials in the Test Kitchen here to guide you in the right direction.

Thanks-