If by “LA-200” you mean the common audio induction-loop amplifier units (such as the Sarabec LA-200), then no — it is generally not a good choice as a front-end amplifier for VLF loop antennas used in SID monitoring.
The main reasons are:
- SID monitoring is usually around 15–30 kHz (e.g. NAA on 24.0 kHz, DHO38 on 23.4 kHz)
- Most hearing-loop amplifiers are designed for audio-band magnetic loops, not ultra-low-noise RF/VLF reception
- Their input impedance, filtering, and AGC are usually unsuitable for weak VLF radio signals
- Many have limited bandwidth below ~50 Hz–20 kHz audio ranges and may roll off or distort the phase response near the frequencies you care about
A proper VLF active loop preamp should instead have:
- Very low input noise
- High magnetic-field sensitivity
- High dynamic range
- Minimal AGC/compression
- Good rejection of electric-field mains noise
- Stable gain at 20–30 kHz
For SID detection, the usual successful approaches are:
- Resonant passive loop + sound card
- Loop + JFET/FET high-impedance preamp
- Differential magnetic loop amplifier
- Mini-whip style active antenna (less ideal in noisy urban environments)
Small magnetic loops are widely used for VLF because they reject local electric-field noise better than whips.
For SuperSID-style systems, a large tuned loop (often 1–2 m square) with a dedicated low-noise preamp is usually superior.
A better match for your radio astronomy/SID work would be something along these lines:
- High-turn passive loop into USB sound card
- INA-based differential preamp
- PA0RDT-derived active loop (modified for VLF)
- Airspy HF+ Discovery directly on a resonant loop
- A simple J310/JFET source-follower at the antenna
The key issue at VLF is usually noise, not lack of raw gain. Too much broadband amplification often makes SID reception worse by amplifying:
- mains harmonics
- switch-mode PSU hash
- LED lighting noise
- Ethernet/Raspberry Pi noise
A tuned loop with moderate gain is often much cleaner than a high-gain active amplifier.