Wiring a 9-pin socket with no center pin

drano81 · 1402

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Offline drano81

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on: May 08, 2019, 01:22:06 PM
I have been searching all over and scanning any picture I can find, but I'd love to get some reassurance before I attempt this...

The stock 9-pin center holds the ground of the two LEDs which connect to A3 & A8. The socket I am using as a replacement does not have a center pin. What is the best way to accommodate that socket? I was thinking of using a 3 lug terminal board, ground to lug 2 (grounded to chassis) and A3/A8 to lug 1 and 3 with the LEDs mounted appropriately between those and ground. I found a post saying something similar to this, but the picture of the completed install is no longer around.

Is this an acceptable way of wiring the LEDs or is there something better/simpler?



Offline Paul Birkeland

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Reply #1 on: May 08, 2019, 03:14:55 PM
The best answer is to use the socket we provide.  If you attempt to solder the LEDs to a terminal strip, the difference in heat required to flow the solder onto the terminal strip vs. the heat required to solder to the LED is significant, which increases your chances of damaging the LED.  If you absolutely have to use this socket, then you can use cathode biasing resistors instead to help make this possible.  We don't think they sound quite as good, so that's why we don't put them in the kit. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline drano81

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Reply #2 on: May 10, 2019, 07:58:30 PM
Thanks for the reply Paul! I'll probably stick with the original socket to minimize any issues. Are those sockets just tough to insert/remove tubes from? I don't believe I've soldered the pins too tight to cause any binding, but it sure takes some effort when changing tubes...



Offline Paul Birkeland

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Reply #3 on: May 11, 2019, 05:56:12 AM
A tight fit is a good thing.  You'll likely find that they loosen up after you've swapped the tubes around a few times.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline mudvin

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Reply #4 on: May 12, 2019, 02:39:45 PM
If you want a good replacement socket get some of the russian PLK9 sockets, They are great, hold the tubes firmly but easy to insert and remove.

Shielded versions at least are drop in replacements, screws line up and correct orientation (and they have a center post, which is rare)

Plenty on ebay,and cheap they come in non-shielded versions and various shielded versions, get 55mm (12au7) or  75mm (e80cc)
« Last Edit: May 12, 2019, 02:52:25 PM by mudvin »



Offline Tom-s

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Reply #5 on: May 12, 2019, 08:00:31 PM
Beware. Once you use a shielded tube socket, the option of using 8-pin (or other bigger) tubes will be gone as the needed adapters won't fit.