I use Shuguang Black Treasure CV-181z in mine and love them. Regarding caps, it didn't look like they are easily replaceable as the circuitry is enclosed in one or two black box(es), which are apparently filled with some kind of compound to prevent resonance, according to Ray. I never really tried to get in there so if you are able to swap out the caps please report back! I would love to get some Duelunds, Audyn True Copper, or Rike S-Caps in there.
For other upgrades I swapped out a pair of input RCAs for WBT 0210-CU and output RCAs for WBT 0210-Ag. Also replaced the Alps volume pot with a Goldpoint Mini-V stepped attenuator with Bent Audio IR kit for remote volume control. The changes made for a pretty significant improvement in clarity, transparency, image definition, and some added treble liquidity, but perhaps at the expense of a little warmth.
What do you think of the preamp so far?
For other upgrades I swapped out a pair of input RCAs for WBT 0210-CU and output RCAs for WBT 0210-Ag. Also replaced the Alps volume pot with a Goldpoint Mini-V stepped attenuator with Bent Audio IR kit for remote volume control. The changes made for a pretty significant improvement in clarity, transparency, image definition, and some added treble liquidity, but perhaps at the expense of a little warmth.
What do you think of the preamp so far?