Carlos from Burson asked if I would be interested in trying out the V5i in combination with the Walnut F1. The V5i was provided free and does not have to be returned. Please note: this review should only be applied to the V5i as installed in the F1. I don't have any other amps available with swappable opamps to try the V5i in, and the F1 is...quirky. I bought a Muses02 to have another point of comparison in addition to the stock opamp, which in my F1 is labeled OPA2134PA. You can't really A/B opamps in a single amplifier, so I compared each opamp...