Boss LM-2B Bass Limiter Cap Upgrade Mod Kit

monteallums — Thu, 04 Jan 2024 22:53:26 +0000

Electrolytic caps in tube amps, over a period of time, start to leak, loose their tolerance and go bad. It’s just the nature of Electrolytic caps. Sometimes the leaking is actually visible. But Electrolytic caps can look okay and still be faulty. By replacing Electrolytic caps in older pedals you can actually improve the overall effect of that pedal. Honestly I was skeptical until I received an email from a client that was having issues after he modded his Boss BF-2 with one of my kits. He said the flange effect was barely noticeable. A couple of weeks later I received another email from the same client. The client said he had solved the issue by replacing all the Electrolytic caps in his BF-2. This peaked my interest so I started experimenting.

I was astonished how some of my older pedals benefited from the cap upgrade! Noise seemed to be reduced and clarity and presence of the effect were enhanced. I am now offering these Cap Upgrade Kits for many of the pedals I offer kits for. In some cases some of these caps are already upgraded in the kits that I offer. But I am offering kits that replace all the Electrolytic caps for those that have not purchased my kits. They will benefit from upgrading the Electrolytic caps that I do not replace in my kits. You’ll find that some of these same caps are already replaced in the kits I offer. It’s a win win all around for those that want the maximum benefit when upgrading their pedals. But I didn’t stop there, when possible I have upgraded these Electrolytics with Metal Film and Tantalum. Not only do these caps have tighter tolerances but they will also last the life of the pedal.

Because of the age of these 30 year old pedals I recommend everyone also purchase the cap upgrade mod. These old pedals that use electrolytic capacitors loose tolerance and get noisy with age. New electrolytics along with higher quality tantalum and metal film caps will breath new life into the LM-2B.

NOTE — The LM-2B I bought for this mod was PSA 9V. But there seems to be a version that is ACA 12V. If you have one of them and can pass on the resistor and diode that needs to be jumpered to make the conversion to 9V it would be much appreciated! That is if that version even exists.

WARNING — These mods only work with the LM-2B and will not work on the LM-2. The LM-2’s circuit is very different than the LM-2B.

Boss LM-2B Bass Limiter Plus Mod Kit

monteallums — Sun, 03 Sep 2023 23:50:46 +0000

The LM-2B was made from 1990 to 1994. Originally targeting bass players it has become a very popular sonic tool of guitarists also! The byproduct of most all compressors is they shave off a bit of the top end frequencies. Since the LM-2B has a built-in enhancer circuit it adds a bit of sparkle for slap bassists and acts as sort of an exciter when used on guitar. The threshold sets the frequencies the limiter hones in on. I really like this on funky guitar chords or slap bass. I find the enhancer really sweetens up the harmonics on a distorted guitar or bass!

The stock LM-2B is terribly noisy and the limiter tends to raise the noise floor which really makes the stock pedal really useless IMO. Noise is probably the reason it had such a short production run. I know there are those that will wonder why I did not use the Burr Brown OPA2134PA in this mod. The OPA2134PA in this circuit, with the enhancer, was just too bright. The 5532 opamps sounded the best. My next favorite opamp was the RC4559 in this circuit. Both really made the circuit come to life with warm and harmonically rich overtones!

NOTE — The LM-2B I bought for this mod was PSA 9V. But there seems to be a version that is ACA 12V. If you have one of them and can pass on the resistor and diode that needs to be jumpered to make the conversion to 9V it would be much appreciated! That is if that version even exists.

WARNING — These mods only work with the LM-2B and will not work on the LM-2. The LM-2’s circuit is very different than the LM-2B.