• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tube capacitor preamplifier

hi i have an Audio Research SP16 preamplifier and i am testing capacitors on the 1uf output.
Originally it brings Rel cap and I have tried Dynamicap and Mundorf evo silver gold and none of these sounds better than the Rel cap they could advise me who is worth it to improve
 
There's a feedback loop around the coupling cap in the SP16 that will tend to mitigate the audible differences that you might otherwise hear from a coupling cap.

The SP-16 also has a PC board with no solder mask that is a bit more vulnerable to repeated soldering, so installing a bunch of different capacitors on the board may destroy the preamp eventually.
 
hi i have an Audio Research SP16 preamplifier and i am testing capacitors on the 1uf output.
Originally it brings Rel cap and I have tried Dynamicap and Mundorf evo silver gold and none of these sounds better than the Rel cap they could advise me who is worth it to improve
Nothing to improve because the original does it job fine.

IF a capacitor "sounds" then it is grossly defective.

Good capacitors (commercial ones made by the large manufacturers and sold at widely known suppliers) are good enough, because they are already acoustically transparent.
There is not "more transparent than transparent".