If you are at all familiar with the line up of boss pedals, then you've probably notice their equalizer pedal. If you've used then you may know that it can get a little noisy. Some of this noise is the pedal just amplifying your guitars signal which is going to have a little noise just by its nature. Using a Equalizer is a great way to boost certain frequencies to shape your tone without doing anything else to your tone. It may not turn your twangy tele into a moody jazzbox, but it wouldn't hurt to add it to your chain to fatten up a rhythm section. This pedal has enough flexibility to make you stand out on leads or have a big fat bottom end. No matter what gets moved or replaced on my pedal board I always keep my handy GE-7 around. So if this is such a great pedal, then why the mod? Well, I did mention the noise. The kit that got from Mounte Allum included no less than 6 opamps. As with most of his mods, this kit included some "hi-fi" passive parts. After I installed this kit I was actually surprised at the difference it made. It turned a good little tool into something great. HOWEVER, I'm not 100% sure why, but this mod makes it so that a 9-volt battery is drained in seconds. So If you are looking into this mod, then be sure to have a power supply on hand.
Here is what Mounte Says:
This is very handy tone shaping tool to have on your pedal board. This is actually a very nice sounding EQ right off the shelf. But it suffers from excessive noise as a result of the cheaper components Boss uses. With this mod we replace the cheaper noisy op-amp chips with low noise higher quality chips.
Lower quality capacitors are also replaced reducing noise even more and also adding a more focused Hi-Fi tone to the circuit. Noise is substantially reduced and the signal is passed through preserving the original tone of your guitar. The bypass circuit is also much improved. You will not find a better mod than this anywhere for the GE-7! You'll be shocked at the improvement this mod will make on this pedal.
Nice article.
ReplyDeleteThe modded pedal drains your battery because the original noisy op-amps required much lower current than the replacement high-performance (ie low noise) op-amps.
The original op-amps were most likely TL022, with an idle current of about 0.13 mA.
The replacements were some combination of OPA2134 and RC4559, both of which have idle currents of about 4 mA.
So the op-amps are using over 30 times the original current when you aren't even playing. In fact, this is true even when the pedal is in bypass.
You could probably replace all of the op-amps with TL072, which has an idle current of about 1.4 mA, and get more life out of your batteries. TL072 is also high-performance, and it is very unlikely you will hear any difference between them and the more expensive OPA2134 or RC4559, especially with a guitar signal. Or you could just use an adapter.
I doubt the cap replacements make any audible difference, but YMMV.
@em induction. Thanks for the comment! I am inclined to agree with you. From what I read you are right on the money about the opamps. Thanks for reading!
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