Pictures of the David monoblock. This is a 1 watt amp using a 12B4 as the output, 6BQ5 as the CCS for the output, 6AN8 as the driver and driver CCS. CCS's are modified BBMCCCS's. The output transformer is the Radio Shack 10 watt 70 volt line matching transformer. These amps sound way too good for what they are. The chassis is from a Motorola mini console and started life as a stereo SE 6BQ5 amp. The driver stage has a CCS fed shunt reg. The shunt reg is 3 100 volt zener diodes with a .056uf Teflon cap across the zeners. To get the increased voltage needed for the active load the power supply was changed from capacitor input full wave center tap to a choke input fullwave hybrid bridge. The choke for the input is one of the original output transformers. The negative half of the bridge is UF4001 diodes, the positive half is the EZ80 rectifier tube that the amp came with.

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