This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
indoor stage EF electron tube battery field pre preamplifier with balanced microphone input primary of transformer with few turns so that proximity effect is compensated stage EF electron tube battery field pre preamplifier with balanced microphone input primary of transformer with few turns so that proximity effect is compensated