Phono preamplifier with RIAA eq .
R.I.A.A @ Work using 5755 - 6072 tubes in cathode follower configuration.
R.I.A.A @ Work. This is the new over designed power supply that is tube regulated and employs one GZ32 one 6V6 one JAN5842 and one 5651A.
Here is a RIAA pre that employs one pair of 6SN7 and one pair of CV569 AKA 5691 6SL7.
This is another RIAA preamplifier with four 5842 current source loaded tubes .