Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: imgumby001 on September 23, 2023, 09:55:08 pm
-
Hello everyone,
I’m going with a 6ak5 in place of the ef86 in Slucky’s Dual Lite British build and I’d like to know what y’all think about the cathode pins on the 6ak5. On the ef slucky has the cathode and g3(k?) tied together at the socket, which is clearly doable with the 6ak. However, when searching around I see some tie pin 7(k,g3) of the 6ak to ground. Does anyone know if there’s a better/safer option between the two?
Thanks,
NR
-
... 6ak5. ... when searching around I see some tie pin 7(k,g3) of the 6ak to ground. ...
You have to be willing to trust your gut when you immediately think, "Well that's dumb..."
The 6AK5 data sheet (https://frank.pocnet.net/sheets/127/6/6AK5.pdf) says Pin 2 and Pin 7 are internally connected, and also connected to both the cathode and suppressor grid.
The schematic-fragment you posted shows a cathode resistor & bypass cap. So apparently the designer wanted to cathode-bias the 6AK5.
If they tie Pin 7 to ground, they short-circuit the cathode resistor & bypass cap. Zero-bias and this tube tries to half-wave rectify the applied signal. So whoever did the schematic drawing made an error, because the sound of the non-functional amp would be obvious to all.
Good job recognizing, "That Don't Make Sense!" You were right all along.
-
Don't connect anything on that 6AK5 to ground!!! Look at Smoky...
http://sluckeyamps.com/smoky/smoky.pdf
-
Seems that the schematic was drawn by me years ago and ..... it is wrong
One error is that was used the shape of an ef86 but was labeled as 6ak5 (the 6ak5 don't has a shield connected to pin #7)
Other "error" is that the shield is drawn in a way it seems connected to the cathode and G3
I apologize
Franco
-
Thanks everyone!!! Gonna go out and wire that baby up right now!!!!!