madbeanpedals::forum

Projects => General Questions => Topic started by: GhostofJohnToad on August 29, 2012, 02:10:45 AM

Title: Max1044 suffix designations - Kingslayer
Post by: GhostofJohnToad on August 29, 2012, 02:10:45 AM
Just was reading over the Kingslayer documentation and noticed the comment about using only 1044SCPA for whine considerations.  What does the "S" mean?  I just built a FSH-1 tonepad board and used a 1044cpa and it does whine.  So cool, looks like I might have a solution with the "s", but just curious what it all means.
Title: Re: Max1044 suffix designations - Kingslayer
Post by: jkokura on August 29, 2012, 02:22:46 AM
CPA parts are known to whine. SCPA are usually the solution. I'm not sure what the S means, but we could assume it means 'silent'.

Jacob
Title: Re: Max1044 suffix designations - Kingslayer
Post by: mgwhit on August 29, 2012, 02:25:16 AM
Those charge pumps use an internal  oscillator that normally oscillates at a frequency that can be very annoying if it bleeds into the audio signal via the power.  The S chips have an internal frequency doubler on the oscillator that can push the oscillation out of the range of human hearing.  Or something like that.

I'm sure it gets dumped to ground by a low-pass filter later on in most audio circuits, so you probably don't have to worry about it irritating your dog.
Title: Re: Max1044 suffix designations - Kingslayer
Post by: TNblueshawk on August 29, 2012, 07:36:53 PM
Yeah, I was thinking it still whines with the "S" but we just can't hear it.

Now about the dog...well...I'm not sure. My cats don't go nuts except when I turn the amp past 5 or something  :P