(14-08-2021 18:27)groove писал(а):  Очень сильно растут искажения с частотой.
Минимальные искажения 0.0005%, что есть намного больше чем у самого СЛ на этих частотах.
На частоте 10К 0.0018%. где у СЛ 0.0005%

И где же найти такой пред, чтобы у него искажения были меньше, чем у УМ? Но, при этом звучащий. Вопрос, наверное, риторический.
Интересующие меня преды Spectral (DMC-30 SV/SC) имеют "меньше, чем 0.005% THD и IM" и стоят при этом совсем каких-то невменяемых денег. И они используют не реле или PGA, а переменник! Хотя и расписывают, какой он специальный и модный:

Цитата:The Spectral ‘Super Fader’ combines mechanical precision, advanced materials science and unrestricted use of exotic materials to create a level control that behaves like an infinite number of theoretically ideal resistors. Inside, the critical moving parts are precision machined from solid precious metals. These wipers have many surfaces that are spring pressured as a group to contact micro-polished optically flat resistance elements. Exemplary mechanical design and fabrication alignment is used to prevent localized heating from circulating currents. Ultra-pure contact metal eliminates solid-state or junction distortions which occur from plated parts used in other controls. When such precision and material commitments are combined, noise and error in the presence of test signals is immeasurable and other performances are very near to ideal thermal accuracy limits. With polished custom element and ball-bearing construction, there is every indication that this superior performance will remain intact even after 100 million operations. The ‘Super Fader’ potentiometer outperforms all existing gain control systems with virtually infinite service life. We hear a clarity and transparency, as if a wire has been substituted for the control.