triode electronics driver board wiring question

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triode electronics driver board wiring question

Postby deathman68 » Wed Jan 11, 2017 5:23 am

Hi all,

It's been a while since I've posted. I've done a search but didn't come up with the exact answer I was looking for. I also tried posting on on another forum but the folks there referred me back over here.

I'm finally getting around to finishing up the wiring on my triode electronics St-70 driver board and have a doubt with regards to Note 1 for Eyelets #4, 5, 15, & 16. Per the instructions note 1 says:

"NOTE 1: These are the input tube filament connections. A stock ST-70 uses the front panel power take-off sockets as a tie point for the input board tube filament wiring. Many amplifier modifications use these socket holes for input jacks or other purposes. If the tube filament power is not present on these jacks or the jacks themselves are not present, then the filament wiring can be run (as twisted pairs to reduce hum) from the output tube filament connection (EL34: pins 2&7). The phase inverter position (V2) now has extra flexibility to use tubes with different pinouts, to use 12AU7, 12BH7, ECC99 solder a wire from J1 to J2 and make your filament connections to eyelets 24 & 25, to use 6CG7, 6922, 7308, or 6DJ8 do not jumper J1 and J2 and instead make your filament connections to J1 and J2 and ignore eyelets 24 and 25."

Specifically I'm planning on using a 12AU7 so per Note 1, I've jumpered J1 & J2 but am unsure about whether or not I should be connecting (or using) Eyelets #24 & 25 for the filament connections since filament power is already present on the front panel power take-off sockets. I've included a photo which shows how I currently have the board wired but wanted to confirm before powering up. I currently have 24 & 25 connected to the filament power for the left side only (eyelets 4&5 to pins 1&2 of the left power take off socket and pins 1&2 also wired to eyelets 24&25). Per the instructions I have eyelets 15&16 wired to pins 1&2 of the right power take off socket only.

Hope this is clear.

Posts: 10
Joined: Wed Dec 30, 2015 3:55 pm

Re: triode electronics driver board wiring question

Postby cdmawolf » Thu Jan 12, 2017 6:25 pm

Unless you are using a Dynaco Pam for your preamp, ignore the wiring to the FRONT sockets.
Go from the EL34 socket to the Driver board.
Posts: 37
Joined: Thu Nov 29, 2012 3:07 am

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