DL4, DM4, FM4 & MM4 Line 6 Audio Grade Capacitor and Burr Brown Opamp Mod

WARNING! — The OPA2134PA opamp, of which are included in many of my kits, is currently extremely hard to find. Mouser and Digikey are currently out of stock with none expected until 2024. I have hundreds in stock. BE CAREFUL BUYING THE OPA2134PA ON EBAY. THE MAJORITY ARE FAKE! Manufacturers in China are rebranding cheaper opamps and selling them as OPA2134PA opamps. I test all my OPA2134PA opamps I buy. You can easily test whether a OPA2134PA has been rebranded. Do this, take some Acetone on a Q-tip and rub across the lettering of the opamp. If it is Fake the ink used to print the labeling will dissolve into the Q-tip.

NOTE: With this Kit you will receive Solder and Desoldering Braid along with detailed easy-to-follow High Rez PDF Mod Instructions sent to you as an e-mail attachment after purchase.

The DL4 is a great delay pedal. I’ve used them in the studio and live for almost 20 years. But as is the case with many mass produced pedals, Line 6 cut a few corners to bring the price point down. The Electrolytic Capacitors Line 6 uses can be upgraded to Audio Grade Capacitors and there are two TL072 opamps in the input and output circuits that can be upgraded.  Together replacing them improves the overall tone of the pedal. 

Electrolytic capacitors, with age, are notorious for leaking, losing their tolerance and going bad. The result can be pedal failure, noise and hum, and generally poor performance of the effect. Just like in tube amps, Electrolytic Capacitors in pedals also go bad with age and use. By replacing them the performance of the pedal is enhanced by ensuring clean power to the circuit. Where possible I replaced electrolytics with high quality Metal Film Capacitors. The Audio Grade Capacitors will take the Harshness out of the circuit.

There are different quality levels of Electrolytic Capacitors.  Here I have chosen Nichicon Audio Grade Electrolytic Capacitors.  These capacitors are some of the best audio grade electrolytics available and will take your pedal to a whole new level in audio quality.  You’ll find they will give you a tighter low end and smoother mids and highs.  For the opamps I chose the Burr Brown OPA2134UA.  These opamps will add clarity and fullness to the effect along with lower noise. 

NOTE: Nichicon Audio Grade Electrolytic Capacitors are getting hard to source. When I can find them I will continue to included them in my kits. But as is the case with many thru-hole components, manufacturers are cutting production and in some cases actually discontinuing components. I will include the best parts availble at that particular time.

Together these changes will push your Line 6 pedal into new tonal territory and breath new life into the effect.  The capacitors are through-hole and are easily replaced.  The two opamps are surface mount (SMD) and are actually not that hard to replace once you get the technique down.  I recommend watching several of the surface mount soldering videos on Youtube.  You’ll find as I did that with the right tools and technique replacing surface mount components can be done with relative ease. 

Even though some of the Electrolytics are not in the signal path I feel they should be replaced.  Especially on the older Line 6 pedals.  Some of these pedals are 20 years old.  Electrolytics, over time, go bad, leak and lose tolerances, which affect the quality of the effect.

IMPORTANT — I am only aware of 2 different Line 6 pcb versions. I am still doing research so there may be more. If you do have a different version than listed here please contact me. Here are the two versions I offer a capacitor and opamp mod for. Please open your pedal up and confirm which version you have and order the appropriate version.

Vintage Version

Newer Version

SoundFile.mp3 — HSS Strat into a OD-308 then into a modded Line 6 DL4 and then straight into a Mac Pro VIA an MBox Pro 3 using Presonus Studio One.