Hey all,
I am working with a liverpool chassis and am looking to install a 5AR4. My question is related to how the tube is oriented with respect to the other components: all 9-pins are aligned such that pin 1 is facing the front of the chassis. Firstly, is the angle itself all that important? If it is, I gathered by studying a few current layouts (36 watt, majestic interstellar flying object*) that pin 8 should be facing forward due to similar relations between the alignment of the 9-pins and the 5AR4. Is this correct? Do I need to take other factors like the transformers and power supply board into account?
Many thanks in advance,
M
5AR4 alignment
Moderators: pompeiisneaks, Colossal
-
David Root
- Posts: 3540
- Joined: Fri Aug 04, 2006 3:00 pm
- Location: Chilliwack BC
Re: 5AR4 alignment
FWIW Fender aligned pins 1 & 2 of the rectifier and power tubes parallel with the chassis rear apron. Normally these tubes are aligned so that the coolest parts of the tubes face each other, which of course makes a lot of sense.
This is done by aligning the tube's internal support pins in line along the chassis. These can be seen exiting the upper mica support. This works with pretty much all the tetrodes & pentodes commonly used in MI power amps. Based on the way Fender did it being for the same reason, I infer it also works with 5AR4, 5Y3GT and 5U4G/GB rectifiers.
This is done by aligning the tube's internal support pins in line along the chassis. These can be seen exiting the upper mica support. This works with pretty much all the tetrodes & pentodes commonly used in MI power amps. Based on the way Fender did it being for the same reason, I infer it also works with 5AR4, 5Y3GT and 5U4G/GB rectifiers.
Re: 5AR4 alignment
Read the book. http://www.mif.pg.gda.pl/homepages/frank/vs.html
5AR4
http://www.mif.pg.gda.pl/homepages/fran ... 5/5AR4.pdf
"Mounting position - Any"
5U4
http://www.mif.pg.gda.pl/homepages/fran ... /5U4GB.pdf
"Mounting position - Vertical(*)
(*)Horizontal operation is permitted if pins 1 and 4 are in a vertical plane."
It is the difference between a well supported heater-cathode construction and a floppy filament construction. FWIW, I've used 5U4 without caring which way was which, but in severe shock the filament can slap and short.
Beyond this restriction on filament rectifiers, you can put tubes any way you want. Neatest wiring, or shortest wiring, or all one way, or at all angles like Smoky Stover's hat.
5AR4
http://www.mif.pg.gda.pl/homepages/fran ... 5/5AR4.pdf
"Mounting position - Any"
5U4
http://www.mif.pg.gda.pl/homepages/fran ... /5U4GB.pdf
"Mounting position - Vertical(*)
(*)Horizontal operation is permitted if pins 1 and 4 are in a vertical plane."
It is the difference between a well supported heater-cathode construction and a floppy filament construction. FWIW, I've used 5U4 without caring which way was which, but in severe shock the filament can slap and short.
Beyond this restriction on filament rectifiers, you can put tubes any way you want. Neatest wiring, or shortest wiring, or all one way, or at all angles like Smoky Stover's hat.
Re: 5AR4 alignment
Thank you for the replies. I installed the tube socket so that pins 1 and 2 would face the rear of the chassis. First test run went very well. There's an ongoing issue with fizzling out, but I'm hoping to cure that by replacing a couple resistors. Once again, thank you all.
-M
-M