6-band EQ

Mike McLane

Active member
Tom Bukovac had some outfit re-engineer the Boss GE-7 to concentrate the EQ bands in the mid range. . . . . A mod that subs parts to accomplish the same things (like the different "flavors" for the Ice Scream) would be very cool.
 

Mike McLane

Active member
If you did the "mid-range thing" could it be possible to leave one band for an overall volume slider (like the GE-7) or would that require a completely different schematic/PCB? I was thinking in terms of a booster that could kick in to hit your drive pedals with some additional volume and mid-range for solos.
 

daeg

Well-known member
Definitely will build the Potentiometer version, but with modified bands. The XTS GE-7 mod looks interesting.

400hz | 800hz | 1.2khz | 1.6khz | 2.0khz | 2.5khz | 4.0khz
xts-ge7-mod.PNG
 

Gordo

Well-known member
So if the first five bands are Sallen-Key Hi Pass Filters the parts values would change to:
400Hz
C568n
C6220n
R1122k
800Hz
C733n
C8120n
R1322k
1.6KHz
C915n
C1068n
R1520k
2.0KHz
C1112n
C1256n
R1724k
2.5KHz
C1310n
C1439n
R1922k
4.0KHz
C1647n
R20820r

But how is the frequency determined in the last band???
 
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Gordo

Well-known member
What am I missing? Is the last band a simple Hi Pass? and if so the math should come out to 2.0Khz but I know the stock design is 3.2KHz...
 

daeg

Well-known member
What am I missing? Is the last band a simple Hi Pass? and if so the math should come out to 2.0Khz but I know the stock design is 3.2KHz...
Yeah, if you look at the MXR 6-Band EQ schematic, it's not a gyrator. It's just a LPF placed across the differential amplifier.

Thanks for figuring out the bands. I really do like the idea of a mid-focused EQ and the 6-band might be the right platform for it.
 

p_wats

Well-known member
Hmm. The potentiometer version is making me think of a stereo build, using two boards, but a single set of dual-gang pots. ?
 

Gordo

Well-known member
Was a bit of a bugger trying to get the two boards apart and then remove a bunch of the caps and resistors but I've changed it all over to the XTS frequencies using the values I posted above and it sounds really nice. I'm looking forward to getting this on my live rig but am not playing for another couple of weeks.
 
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