Author Topic: Question about MXR distortion+ schematic  (Read 3392 times)

Ghost Planet

Question about MXR distortion+ schematic
« on: December 26, 2012, 04:20:39 PM »
I found this MXR distrotion + schematic that has some really cool mods I want to try. I just have quick question about the schematic. R5 has a 1M value, and under the resistor it says 4.5v. Does this mean you connect the 9v power supply here as well as pin 7 on the IC? Is 4.5v the voltage after it passes through the 1M resistor?

Govmnt_Lacky

Re: Question about MXR distortion+ schematic
« Reply #1 on: December 26, 2012, 04:22:48 PM »
The 4.5V is most likely the BIAS voltage. This is created from the 9V input and is used to bias the op amp and other parts of the circuit.

Link to schematic to verify??
« Last Edit: December 26, 2012, 04:25:05 PM by Govmnt_Lacky »
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Ghost Planet

Re: Question about MXR distortion+ schematic
« Reply #2 on: December 26, 2012, 04:29:55 PM »

Govmnt_Lacky

Re: Question about MXR distortion+ schematic
« Reply #3 on: December 26, 2012, 04:57:00 PM »
That is only a PARTIAL schematic of the circuit. That schematic DOES NOT show how the 4.5V Vref is created.

Here is a better "stock" schematic that shows how to get the 4.5V:

http://www.generalguitargadgets.com/pdf/ggg_dist_plus_sc.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

Good Luck  ;D
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

Ghost Planet

Re: Question about MXR distortion+ schematic
« Reply #4 on: December 26, 2012, 06:15:47 PM »
Not cool, don't post a partial schematic, it leaves us newbies scratching our heads. Thanks for the help.

Steve Mavronis

Re: Question about MXR distortion+ schematic
« Reply #5 on: December 26, 2012, 06:34:23 PM »
Here's a re-drawn schematic that I made of a 1976 MXR Distortion+ based on a MXR factory schematic diagram. I find it interesting how manufacturers style the layout of their products vs user traced schematics from studying pedal circuit boards and wiring:



And here's a scalable PDF version of the same good for printing:

http://home.comcast.net/~snmavronis/mxr_dist+_schem.pdf

Guitar > Neo-Classic 741 Overdrive > Boss NS2 Noise Suppressor > DOD BiFET Boost 410 > VHT Special 6 Ultra Combo Amp Input > Amp Send > MXR Carbon Copy Analog Delay > Boss RC3 Loop Station > Amp Return

Govmnt_Lacky

Re: Question about MXR distortion+ schematic
« Reply #6 on: December 26, 2012, 06:44:51 PM »
Beat you to it Steve!  ;)

Just PM'd a link to your D+ thread.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

Steve Mavronis

Re: Question about MXR distortion+ schematic
« Reply #7 on: December 26, 2012, 07:18:22 PM »
Beat you to it Steve!  ;)

Just PM'd a link to your D+ thread.

Thanks! :)
Guitar > Neo-Classic 741 Overdrive > Boss NS2 Noise Suppressor > DOD BiFET Boost 410 > VHT Special 6 Ultra Combo Amp Input > Amp Send > MXR Carbon Copy Analog Delay > Boss RC3 Loop Station > Amp Return