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How to use a relay to switch the Hot switch gain mod.
This is a close up of the relay socket that I stock. You can pop pins in and out of the socket. The relays I stock have 8 pins and they pop right into the socket. Note that the relay pins spacing is too close on two of the pins and so you have to use the next set of pins and create a jumper on both sides of the relay socket. The turret lugs cannot be any closer than 5mm or they will touch each other. See the pictures below for more info.

Turret lugs mounted on a board. Ready to accept the relay socket. Note the two pins that have been cut short and will be jumpered.

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(1) Relay popped onto the socket. Note that the last two relay pins on the left fall between the lugs. This is why they are jumpered to the last two lugs on the left.
(2) Another shot of a board with the Turret lugs spaced at 5mm for the relay socket.
(3) Rear of board. Cut the relay socket pins flush with the back of the board and then solder them to the lugs. Note that the relay socket pins are only soldered on the rear of the board. On the back side of the relay socket, I have installed a 1n4001 diode to prevent kickback from the relay coil. There is a jumper between pins 3 and 5. The white wires lead to lugs.

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Here's some shots of a more recent project where I have refined my relay mounting a bit more.
(1) I have added 4 lugs around the relay socket lugs so that I have better points to solder external wires to. Wires that lead to tube sockets, pots, etc are soldered to these extra lugs. It's much easier and better this way, it can be very difficult to solder to the lugs under the relay socket. Note that these extra lugs are jumpered under the board with short pieces of buss wire.
Note how I have carefully soldered shut the last two holes on the relay socket. The relay does not fit into these holes but the lugs underneath are used via the jumpers.
(2) Here's a good close up of how I solder a jumper on the relay socket. The lugs to the left of the short pins have a flange on the top of them that sticks out a little too close to the short pins. It is very easy to mistakenly solder this flange to the short pins. I trim the flange off the top of the two lugs left of the jumpered lugs. See the red line in the image. Next I very carefully solder a solder blob across the two short pins and the lugs on the right end of the relay socket. You need a very sharp soldering iron tip and not very much solder to do this. It takes some soldering skills to get this done properly without soldering across the red trim gap.
Note how I have carefully soldered shut the last two holes on the relay socket. The relay does not fit into these holes but the lugs underneath are used via the jumpers.
(3) The back side of the relay socket. The yellow rectangle in the photo is where the actual relay socket sits, the lugs outside the rectangle are attachment points. I have installed the 1n4001 diode and the jumper between pins 3 and 5 on the back of the socket. If you compare this picture with the front side picture, you can see where the bare jumper wires go. They go to the four extra lugs I added for attaching wires and they also go to other lugs that are direct attachment point with no external wires.
 Cut the relay socket pins flush with the back of the board and then solder them to the lugs. Note that the relay socket pins are only soldered on the rear of the board.


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