[Harp-L] Squeal Killer anti-feedback pedal

[Chad Nordstrom]

You cannot patent a circuit. If that were the case there would not be the Marshall JTM from the Fender Bassman or any of the hundreds of thousands of amp clones or any of the millions of pedal clones. Even the original Fender amp designs were just Western Electric example circuits. The basic designs has been around for a long time.

As you have pointed out these are not new designs and they have been around for a very long time. 

As for this specific product people can buy what they want. Its value is not just in the parts. All pedals only cost about $30 to build in parts.  It is if that assemblage of parts works for someone’s needs and they are willing to pay. 

> On Sep 11, 2023, at 3:00 AM, Ronnie Schreiber <autothreads at xxxxx> wrote:
> 
> I'm not going to knock someone for being able to sell 5 resistors (including a 5 watt wire wound in a low current 9V circuit!), a small electrolytic capacitor, some connector strips, a 12AT7 preamp tube, an enclosure, a wall wart power supply, and some jacks for $300, but this is what an engineer who I hire to design circuit boards says about the Squeal Killer:
> 
>> The squeal killers tube could probably be replaced by a ~47pf cap. Pretty astonishing he was able to patent that circuit! You’re right, it’s just in there for marketing, and it’s probably working! I showed it to some of the PhD’s at work and they all had a good laugh. Essentially he’s using the parasitic capacitance of the tube and no signal is passing _thru_ the tube.
> 
> I'm not saying it doesn't work. It probably works as well as any other simple notch filter or EQ will, but I think that's pretty much what it is, low pass and high pass filters where one of them is using a tube as a capacitor. If I'm wrong, please correct me. Heck, adding a pot to give you some control would have just added about 80 cents to the cost of the circuit, but then they'd have to drill another hole in the enclosure.
> 
> Disclaimer: I make the Harmonicaster, the electric harmonica that is feedback free in normal playing conditions, but if I find an anti-feedback circuit that works and is not too expensive to produce, I'll gladly make and sell them to harp players who are married to their microphones.
> 
> Ronnie Schreiber
> The Electric Harmonica Co.
> http://www.harmonicaster.com
>