Author Topic: Mu-Tron Phasor II question - diode to IC power  (Read 228 times)

andy-h-h

Mu-Tron Phasor II question - diode to IC power
« on: April 08, 2021, 06:44:25 AM »
Hello

Quick tech question on the Phasor II - if there is such a thing as a quick question for a phaser.  One IC has a diode feeding power to V+.  I was planning on using a TL074 as part of my layout, and was wondering what, if any impact this would have. 

So can I either not use the diode, or should I keep the diode in the circuit, and hopefully this will not bother the other 3 opamps in the TL074? 

Long story short, I pretty much finished a vero layout, and missed the diode...   :icon_redface:  I'm now wondering if I wasted my time.   

EDIT:   SCHEMATIC INCORRECT - 470n on IC6B should be across 6 & 7.  5 to ground.  39k resistor to 6.


« Last Edit: April 08, 2021, 06:05:48 PM by andy-h-h »

garcho

Re: Mu-Tron Phasor II question - diode to IC power
« Reply #1 on: April 08, 2021, 09:52:16 AM »
The diode is for reverse polarity protection, it doesnít do anything until you plug the wrong thing into the dc jack. Then it stops your ICs from getting fried. Forget about it, itís fine with or without, donít worry about quad vs dual, it doesnít matter in this case at all. Just donít use the wrong polarity power supply!

EDIT: there can be instances when having an LFO in the same package as your audio signal might end up giving you noise problems. Or not.
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andy-h-h

Re: Mu-Tron Phasor II question - diode to IC power
« Reply #2 on: April 08, 2021, 05:06:45 PM »
The diode is for reverse polarity protection, it doesnít do anything until you plug the wrong thing into the dc jack. Then it stops your ICs from getting fried. Forget about it, itís fine with or without, donít worry about quad vs dual, it doesnít matter in this case at all. Just donít use the wrong polarity power supply!

EDIT: there can be instances when having an LFO in the same package as your audio signal might end up giving you noise problems. Or not.

Thanks Garcho - the Phasor runs off mains voltage and has a power supply in the pedal.  I'm not sure that polarity protection is needed in this case, as the internal supply already takes care of this.   


garcho

Re: Mu-Tron Phasor II question - diode to IC power
« Reply #3 on: April 08, 2021, 05:54:51 PM »
Ha, duh! Sorry, answered too fast. How come you're recreating the mains power supply?
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andy-h-h

Re: Mu-Tron Phasor II question - diode to IC power
« Reply #4 on: April 08, 2021, 06:03:14 PM »
No problem - also I just discovered the schematic is incorrect (incorrect schematic replaced).  :icon_redface:   I'm not recreating the mains supply, I'll use a standard 9v in.

The 470n cap should be across 6 & 7, with 5 to ground.  Input via 39k resistor to pin 6.
« Last Edit: April 08, 2021, 06:18:43 PM by andy-h-h »