gres
Full Member level 4
Assumptions:
Amplituners from 510x family are still one of the best analog constructions from Poland.. biggest problem with them are stereo decoder, that is old construction. Original decoder is based on UL1601 integrated circuit, that is clone of Sanyo Electric LA3301, works based on archaic method - separate signal from remote control, reinforce it and duplicate at rezones LC circuits. My main target was to build stereo decoder that allow to listen UKF-FM at high quality.
I believe that best chipsets are Sanyo LA3410 and LA3401. those chips consist oscillators that can be stabilize by piezoceramic resonator, so doesn't need to be adjust. LA3401 is better couse has mute function and signal switch. Although that i used LA3410.
Diagram of PSD block
Input signal is given by separating condenser C1 into 2 US1 finishing lead. Power voltage is given via R1 resistor to US1 integrated circuit. Condensers C4 and C5 eliminate interference at power rail. Mono/stereo switcher is build up of T1 transistor, D1 diode is a electronic switcher. Uncode output signal is taken from 4 and 7 finishing leads of US1. in feedback works R6 R7 C9 C12 elements, those paramteres allow to omit output amplifier from PSD module. R8 element is bigger than original because of need to omit T302 and T309 transistors.
If you want to build the same device, helpfull will be stereodecoder PSD module that will be base for swap elements like MPX filters and edge connector. Saving original decoder will also allow to make audio tests. New modules you can buy at RADKOM internet shop.
More information at : https://www.elektroda.pl/rtvforum/topic1533299.html
