The Pathos TT is extraordinarily good stock, owing largely to the Inpol circuit design and good quality transformers and chokes. However like all but the highest end amps it uses cheap capacitors and resistors, and upgrading both can make it sound good enough to compete with all comers. Replacing the four 1uf coupling capacitors is the biggest "bang for the buck" upgrade. I had them replaced with Mundorf Silver/Gold/Oil capacitors in my TT RR, and had several other capacitors replaced with Blackgates, and several resistors replaced with Audionote. My modified TT retains the timbral accuracy and SET sweetness of the stock unit, but adds improved dynamics, three-dimensionality, and bass slam. With these modifications it is one of the two or three best sounding integrated amps I have heard at any price. Next: adding Bybee Music Rails.