We have a super clean Capi 553F in the house!
This is an API type 500 Series equalizer, hand built in the USA.
This unit contains the GAR1731 (2010-2015) , GAR 2520, and the EA2503 Output Transformer.
The 553F is an inductor based EQ with fixed shelving frequencies at 10kHz and 100Hz and a peaking mid-band at 2.5kHz. It also has switchable filtering with the LPF at 12kHz, 22kHz or 28kHz and the HPF at 30Hz, 70Hz, or 110 Hz... each in either a one or two pole configuration. Unlike the 550a, the CAPI 553F HPF and LPF can be engaged separately and with a variety of frequency points.
Ships safely and swiftly!