LEADER LAG-66 SINUSOIDAL AUDIO GENERATOR - This unit came from a swap with 2 14" PC CRT monitors, and a Windows98® license that I had. It was may of 2005. Together with it came the LSG-532, the F-01, the WV-98C, the HD-1, the STR-307, the O-11, and the 944. The fellow who made the swap with me said that these rigs were from his father, who passed away in early 80's, and the rigs were locked at his father's house. He sell that house and he was leaving it empty. Luckily it is on my block, and I was just passing by, and I saw a man carrying the O-11. There still a lot of things that I didn't stay with. I will try to contact him to see if he is interested in sell me the other rigs.
The rig was not working and, as always, I have no information about it. Inspecting the unit I saw a lot of capacitors damaged, the input filter and the capacitors of the ranges switch. They were old high-end Nichicon capacitors. Well, I selected the best Epcos film capacitors I could found and replaced all of the old ones. Needless to say, the unit start working, but with a lot of problems on the switches. After a careful cleaning of them, the problems vanished.
I replaced the power cord and inserted a line filter on it.
Despite of no information I had about it, it is, indeed, two instruments in one. On the left side you have the analogue frequency meter. It measures from 20Hz to 100kHz in four ranges. A switch choose if you want to measure the internal frequency generated or an external. The external input can be up to 300V, but it is not specified if it is peak to peak, or RMS. The ranges switch is ganged with both the frequency meter and oscillator range. On the right side you have the sin oscillator. Double T type, as I could see. The Voltmeter is at the right side and it is calibrated in RMS Volts and dB, under a 600 ohm load. You can choose internal or external 600 ohm load with a switch.
The staff that designed this rig though about audio design, and a lot of features you can extract from this unit. The output has a pretty good sinusoidal shape and low distortion. If you saw one of these around for a good price, grab it!
The closer analogue frequncy meter I found on the web was the Heathkit AF-1 audio Frequency Meter, see the schematics and specs of it. Like the VP-526A, I think this is the first website mentioning this equipment.