Print Page - Rebot 2.5 question on 5pf

Title: Rebot 2.5 question on 5pf
Post by: iccaros on July 15, 2011, 10:31:23 PM

So tossing out the 20% rule, the closest I could find to a 5pf was a 3.5 with out waiting weeks on an order or paying more in shipping then in caps..

the question, the 5pf that is in parallel with the 510K resistor on the negative feedback circuit of second side of the opamp, should stabilize the NF and roll off anything above 64K about, changing to 3.5 put us around 94K still out of human hearing.. so would this destabilize the opamp for the design, or would any <10 PF cap do the trick with 5 being in the center design grab?

Title: Re: Rebot 2.5 question on 5pf
Post by: MikeH on July 15, 2011, 10:42:07 PM

Should be fine - I think I used a 10pf in mine...

Also fyi - for really low pf caps, you can actually make them out of two pieces of insulated wire twisted together; I think I saw it in an Anderton book

Title: Re: Rebot 2.5 question on 5pf
Post by: iccaros on July 15, 2011, 10:56:28 PM

Quote from: MikeH on July 15, 2011, 10:42:07 PM
Should be fine - I think I used a 10pf in mine...

Also fyi - for really low pf caps, you can actually make them out of two pieces of insulated wire twisted together; I think I saw it in an Anderton book

Thanks
I was showing my kids how to make caps with aluminum foil and wax paper..
but I was getting more than PF.. :)

Title: Re: Rebot 2.5 question on 5pf
Post by: Fp-www.Tonepad.com on July 16, 2011, 06:19:27 AM

10pF is fine.
Fp

Title: Re: Rebot 2.5 question on 5pf
Post by: iccaros on July 17, 2011, 12:34:57 AM

Quote from: Fp-www.Tonepad.com on July 16, 2011, 06:19:27 AM
10pF is fine.
Fp

Thanks... By the way great boards.. I am putting two of them in an enclosure.. already have two people who want a double rebot.. will be ordering more boards..

DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: iccaros on July 15, 2011, 10:31:23 PM