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MXR Flanger

1/24/1997 10:25 AM
MXR Flanger
I have a mxr flanger model #117 The filter cap shorted and the regulator blew a hole right through the markings. Does anyone have a schematic and can tell me what this device is? Thanks. Steve
2/1/1997 11:40 AM
Mark Hammer
Re: MXR Flanger problem
Is this the dark grey wide-rectangular one with the footswitch in the  
corner? If so, odds are that the regulator is a conventional +15V 3-pin  
one (7815CT). Since this flanger is around 18-20 years old, one of the  
reasons for its demise may be the drying up of the white heat-conducting  
compound between the regulator and the board. You probably want to make  
sure you guarantee dissipation of regulator heat when installing a new  
one by putting in some of that goop, and may even want to consider finding  
some kind of heat sink that fits the available space. I'd tell you what  
would fit, but I sold mine in 1984.  
I don't know EXACTLY what the filter cap value is, but if you got hold of  
a standard 1000uf/25v electrolytic, you're probably at spec or better.  
While you're in there, the 4558's used in the MXR Flanger are bloody  
noisy (as is the unit in general, which is why I sold mine). If you're  
handy with such things, you might want to desolder the 4558's, put sockets  
in, and try replacing them with lower noise TL072's or NE5532's, either  
of which should be a damn sight quieter.  
Another trick to consider is to trace the Regeneration control back to the  
board and see what the value of the capacitor is which leads up to the  
input of the control. Replacing it with a smaller value (1/3 to 1/2?)  
will allow you to crank up the regeneration without getting the "honky"  
boxed-in sound. If you don't mind drilling a hole, a toggle-switch to  
go from one cap value to another can give more variety in tone.

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