Tuesday, June 19, 2018

Boss GE-7 Noise Reduction Mod and Review

Noise Reduction Modification

The main "problem" with the stock GE-7 is a little bit of hiss.  If you turn the 100 and 200 Hertz sliders all the way down you can hear it.  If you start boosting mids, treble, and level, you can hear it even more.

There are popular "mod kits" out there that involve a bunch of capacitors, but I decided to take a different approach to my mod.

I only want to change the 3 Dip-8 op amps.  Simply clip the left or right 4 legs of the op amps with small dykes, then bend and break the other half.  Remove the remnants of the legs with tweezers and a hot soldering iron.  Clear the holes the best you can with desoldering braid or a better tool if you have one.  Solder in some gold-pin sockets for best results (cheaper sockets are less reliable over time.)  Then insert three NE5532 op amps into the sockets and put the pedal back together.  Make sure they're oriented in the correct direction.  (There's a helpful graphic on the PCB.)  The job took me less than half an hour.

Now when you plug it back in, if it works, the noise should be very low, much quieter than most guitar pickups, or other gain pedals.

The reason I wanted to leave the tantalum capacitors in place is I like the way they sound.  To me this is a "tone" pedal not just a simple equalizer.  I have a cheap Donner EQ from Amazon that doesn't have the character of the GE-7.  It's clean and clear, yeah, but I think the GE-7 has a character that I really like.  It's "warm" to use a wide-ranging cliche.  Vintagey but clean enough.  Hurts my brain a little bit to type that out.

Some famous examples of gear using tantalum capacitors include the Neve 1073 channel strip, the Red Llama and MXR Distortion+ pedals, and the Telefunken ELAM 251 microphone.  If those circuits need to sound cleaner I'll tell you you're crazy.  There is a subtle character related to the caps.  Audio, and especially guitar, is not always about test measurements, but "Tone, mannn."  If the sound is happening then why have a temper tantalum?

It's also not a great idea to swap the caps because any deviation in capacitance value will change the operating frequency of the band it's related to.  If you do change caps, make sure to use exact values.  I just don't see any reason that electrolytic or ceramic caps would be desirable, unless you just don't like the way the GE-7 sounds.  They won't help the noise floor any.  The noise reduction comes from the NE5532 op amps which have a much lower self-noise than the stock JRC '22' op amps from Boss.  NE5532 cost about 35 cents apiece.  They do draw marginally more current than the stock op amps but I don't think it's something to worry about unless you're a battery dude.  I hate batteries.

So the whole GE-7 mod suite, Dantone version, costs about $2.50 and half an hour of labor.  I do hate noise, and tend to "kill it with fire."


My initial reaction to the GE-7 is "Why did it take so long for me to have this."  My 19-year-old guitar brain thought it was some sort of boring "utility" effect but in practice it's so much more.

I've been reading a lot about how Queens of the Stone Age, and Converge, get their "secret sounds."  A big part of both of their approaches is massive mid boosts into cranked up amps.  Kurt Ballou, in particular, is known for using the GE-7, and the EMG 85 bridge pickup, for most of the classic Converge sounds.

It gives a totally different sound than an overdrive, treble boost, clean boost, etc.  It's something you need to hear for yourself to believe.  The resulting tone is fat and crusty, like the amp is about to explode or catch on fire.  You can tailor the brightness, or bassiness to taste as well.  It's nasty.

The cool part is the amp is where the crunch is coming from, not some diode circuit or whatever.  Pushin' doze' toobs makes me evil smile and inspires the playing.  My Marshalls love this effect.  Blues licks sound extra bluesy.  Putting a fuzz in front of the GE-7 is also pretty stoneriffic.

The last picture below shows a typical setting of mine.  Boosted mids with the level all the way up.