https://johnamplifiers.webs.com/apps/photos/ Preamplifiers A mixer preamplifier I have build in 1980. Still working ! https://johnamplifiers.webs.com/apps/photos/photo?photoID=198997807 198997807 An unknown maker preamplifier . The only info available is the label in the front panel (Amplifier type 5214/7) https://johnamplifiers.webs.com/apps/photos/photo?photoID=199020242 199020242