Would you idiot-check my blend implementation here?

Forum dedicated to helping people debug and troubleshoot non-functional pedals or builds. Please use an clear and informative title, indicating circuit and basic problem. Don't forget to mark the issue as fixed if this is the case.
Post Reply
User avatar
tonymcbony
Breadboard Brother
Information
Posts: 138
Joined: 25 Aug 2008, 13:08
Has thanked: 22 times
Been thanked: 18 times

Post by tonymcbony »

Hi folks,

Got a simple thing here: blending a Flatline comp with a TS variant.

I've gotten a bit overwhelmed with the variation of how to do blending/mixing properly and have ended up with a bit of a chimera of how the Pork Loin and Sparkle Drive do their thing. I thought the dual gang mixer was the best way to do blending so I went with that. I'm just trying to triple check that I've gotten the mixer part right - I've buffered the input, which splits out to the two circuits, goes to the dual gang mixer and then has a master vol on the last opamp (which is inverting)

Is there any gotchas here that I haven't spotted? I'm wondering if I even need that input opamp buffer, and whether that could be put to use elsewhere, maybe as a simple opamp boost or something.

I'd be grateful if y'all could cast your eyes over it.

Image
Top
User avatar
deltafred
Opamp Operator
Information
Posts: 1652
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 808 times
Been thanked: 299 times

Post by deltafred »

Can't see the image, don't think I have permission.
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012
Top
User avatar
tonymcbony
Breadboard Brother
Information
Posts: 138
Joined: 25 Aug 2008, 13:08
Has thanked: 22 times
Been thanked: 18 times

Post by tonymcbony »

deltafred wrote:Can't see the image, don't think I have permission.
Hmm, ok.

How about this?

Image
Top
User avatar
tonymcbony
Breadboard Brother
Information
Posts: 138
Joined: 25 Aug 2008, 13:08
Has thanked: 22 times
Been thanked: 18 times

Post by tonymcbony »

A cheeky bump to ascend above the spam
Top
User avatar
deltafred
Opamp Operator
Information
Posts: 1652
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 808 times
Been thanked: 299 times

Post by deltafred »

tonymcbony wrote:A cheeky bump to ascend above the spam
Yes it's a PIA.

The blend should be ok but I would have added another decoupling cap between IC2_C output (pin 8 ) and pot CLEAN_B /3 (as C14 is for the upper path) and connected the pot 'cold' ends to GND. This way there will be no risk of adding any noise onto VR.

All opamps except the output buffer are non inverting so no problems with phase inversions in either signal path.
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012
Top
User avatar
tonymcbony
Breadboard Brother
Information
Posts: 138
Joined: 25 Aug 2008, 13:08
Has thanked: 22 times
Been thanked: 18 times

Post by tonymcbony »

deltafred wrote:
tonymcbony wrote:A cheeky bump to ascend above the spam
Yes it's a PIA.

The blend should be ok but I would have added another decoupling cap between IC2_C output (pin 8 ) and pot CLEAN_B /3 (as C14 is for the upper path) and connected the pot 'cold' ends to GND. This way there will be no risk of adding any noise onto VR.

All opamps except the output buffer are non inverting so no problems with phase inversions in either signal path.
Yeehaa! Thank you sir.
Top
Post Reply

Return to “Pedal Debugging & Troubleshooting Support”