|The Compact Tube Hybrid Amplifier|
Board Silkscreen Images
|CTH Board Silkscreen (150dpi PNG)||CTH Board Silkscreen (600dpi PNG)|
|CTH Board Silkscreen (300dpi PNG)||CTH Board Silkscreen (PDF)|
It's a good idea to study the board and components. Also, look at the schematic diagrams to locate each part on the layout. Measure each resistor before you install it to make sure that you're reading the code properly.
These two diagrams show you exactly where the different transistor types are located. There are so many transistors on this board it is easy to mix them up. Please use these diagrams to get this right the first time.
|CTH Transistor Locations (JPG)||CTH Transistor Locations (PDF)|
These diagrams are courtesy of Ric Lee.
Board Assembly Instructions
The board is very compact with a high density of components. Note that some of the resistors are tombstoned. Pay attention to their part labels. Take your time!!!!
Have the components specific to your build in the parts box.
Warning: Don't ignore the C5P/C10P section below.
Solder the components to the board from lowest profile to highest, roughly in this sequence:
- Resistors and diodes (flat placement first followed by tombstone placement). Do not install D5H yet.
- Mount vertical diodes with cathodes up and anodes down, like this:
- Transistors and IC2S (TLE2426). Mount the transistors low to the board to make vertical space for the off board components.
- Film capacitors, trimpots, opamp sockets, and connectors.
- Small electrolytics, K1E, L2H, D5H. See tweak for C3H.
- Tube socket.
- PS regulators and their heatsinks.
- LED wiring if you will be lighting the tube.
- Large electrolytics C5P and C10P (see below before you do this).
- Install the Opamps. Be sure to get the correct orientation. Note that the dual opamp goes in between the two output buffers.
Mounting C5P and C10P
The first prototypes had these caps at 16mm diameter. But, because the enclosure is so small these caps had to be tilted inward to make room for the top to slide on. These parts were changed to 12.5mm diameter parts. They should be mounted towards the center of the board as shown in this drawing:
Clean up the solder flux residue from the board with isopropyl alcohol (or electronics flux remover) and a brush.
Inspect all solder connections carefully, using a magnifying glass, to make sure there are no solder bridges or cold solder joints. Use a multimeter in ohms scale to check for short circuits. Correct any mistakes before proceeding.
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