Tag: UV-201a

UV-201a DHT Preamp Revisited


I previously implemented a preamp with the UV-201a. These are very old globe valves, somehow fragile and hard to get in good shape. Despite all this, it’s a superb valve. I have managed to acquire a decent set of them to pair the best valves to use in my preamp.

Recently I developed a prototype PCB for the source follower circuit. The source follower is ideal to place at the output of this preamp due to its low driving current. My 4P1L PSE amplifier will be pleased with more current to pump the Miller capacitance effectively. 

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01a Preamp Build: UV-201a version – step 1

This is what I managed to do with a couple of hours at the workshop. Time is gold for me these days. Quick drilling and fitting the main components. You can’t get a smaller preamp than this one. It’s quite packed:

Planning the layout before drilling
Back panel with all connectors (supply and signal)
Inside the preamp
Close look at the gyrator boards
UV4 sockets with rubber dampers
Fitting a pair of brass base UV201a

Next, soldering. Yay, just looking forward to my favourite part of the build process

 

UV4 PTFE sockets

Looking to build a new 01a Gen2 preamp shortly. This time will be for the rare UV-201a valves. They need a special socket UV4 rather than the usual UX4. See width difference of both filament pins. In the UV4 all pins have same size as below:

image2 Weather they have brass or bakelite bases, the new UV4 sockets produced by Luciano Bandozzi (Jakeband) are of supreme quality. I highly recommend them:

image1I already reviewed these and you can see more info here. I hope to post some pictures of the new preamp shortly