madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: hammerheadmusicman on January 12, 2013, 04:15:13 PM

Title: Autobahn - more quack?
Post by: hammerheadmusicman on January 12, 2013, 04:15:13 PM
have built the Autobahn, all working sounds great! But i might be wanting a little more quack on tap, the only sub i made was C8 - instead of an 8n2 i have a 10n in there, i only have 10n or 6n8 to hand (waiting for my tayda order to be delivered!).

would this affect the amount of quack? Also, some positions on the controls seem to have almost a 'straight through signal' quality..

is this normal?

The schematic is here > http://www.madbeanpedals.com/forum/index.php?topic=7621.0

Thanks

George
Title: Re: Autobahn - more quack?
Post by: stecykmi on January 12, 2013, 06:30:16 PM
haven't yet built this circuit, but C8 seems to be in the envelope generation circuitry. playing with it won't have much effect on the filter, it seems to be there to smooth out the envelope a little.

you can change the filter by playing with C3 and C4, the pair of 22n caps. you may have trouble getting it to sound more like an inductor-based wah because the implementation is totally different. playing with the feedback _may_ give you a response you prefer, so if you're feeling adventurous, lowering R7 and R16 could help.
Title: Re: Autobahn - more quack?
Post by: hammerheadmusicman on January 12, 2013, 07:55:25 PM
cheers for the advice, i'll socket those four and play with it a bit!

George
Title: Re: Autobahn - more quack?
Post by: midwayfair on January 12, 2013, 11:16:51 PM
Some great info here:
http://revolutiondeux.blogspot.co.uk/2012/07/mad-professor-snow-white-auto-wah.html
Title: Re: Autobahn - more quack?
Post by: hammerheadmusicman on January 12, 2013, 11:24:32 PM
Thanks Jon, as always! very interesting!

George
Title: Re: Autobahn - more quack?
Post by: chordball on January 13, 2013, 04:07:26 PM
Quote from: midwayfair on January 12, 2013, 11:16:51 PM
Some great info here:
http://revolutiondeux.blogspot.co.uk/2012/07/mad-professor-snow-white-auto-wah.html

Exactly what I was going to suggest. I wasn't really happy with the SWAW's I built until I changed that cap and diode.
Title: Re: Autobahn - more quack?
Post by: hammerheadmusicman on January 13, 2013, 04:56:10 PM
that particular diode is in the post from tayda, and should be here in the next couple of days, i'm on it when my delivery turns up!

G