The opamp PCB seen from the front with the top case removed.

A more advanced opamp mod is the replacement of the original opamps for a THS4032CD. However, the THS4032 is a surface mount IC. So a special adapter PCB is required. The THS4032 is then soldered onto that PCB in the correct position.

In order to avoid high frequency oscillation, a 100nF decoupling capacitor is soldered across pins 4 & 8 of the THS4032.

For non-headphone users the use of just one THS4032 in the LINE OUTPUT circuit is all that is required.

Headphone users can replace both opamps with the THS4032.

A less complex solution to the THS4032 is the use of the metal can version of the LM4562NA, which is better known as the LME49720HA. The following picture shows the pin layout of the LME49720HA as seen from above ( i.e. reading the printing on the top of the casing)

For LINE OUTPUT use, only one LME49720HA is required.

For high-end headphone use, both original opamps can be replaced with a set of LME49720HA.