Apex 460

[haysonics]

Howdee,

Could someone please direct me to pics that show where easy solder points are for the plate on the first stage of the tube + the ground? I wish to solder in a 200 pF styrene capacitor to roll off a bit of the high end.

 

[Khron]

Howdee,

Could anyone direct me to a pic that shows where the points are for the plate on the first stage of the tube and the ground are ? I wish to solder in a 200 pF styrene capacitor to roll off a bit of the high end.

https://groupdiy.com/threads/apex-460-noise.53875/ (Apex 460 schematic)

https://www.amplifiedparts.com/tech-articles/12ax7-tube-diagram (12A_7 tube pinout)

Google is your friend

 

[haysonics]

Thanks but i am hoping there may be pics of soldering positions on the pcb or even a pic showing the capacitor in place from someone that thas done the mod.

 

[Khron]

Thanks but i am hoping there may be pics of soldering positions on the pcb or even a pic showing the capacitor in place from someone that thas done the mod.

the plate on the first stage of the tube + the ground

How about pin 1 or 7, and pin 9 respectively?

 

[haysonics]

Oh ! I just place the capacitor between 2 pins on the tube socket to create the LPF ?

 

[Khron]

Oh ! I just place the capacitor between 2 pins on the tube socket to create the LPF ?

Isn't that precisely what you asked?

 

[haysonics]

Errr, I suppose so. I just assumed it would be connecting 2 spots on a PCB like this (but instead, the equivalent spots on the 460's PCB) :

 

[Khron]

Errr, I suppose so. I just assumed it would be connecting 2 spots on a PCB like this (but instead, the equivalent spots on the 460's PCB) :

The "equivalent spots" are there, just not quite as conveniently accessible as on that C12 board (which also has a simplified circuit).

 

[haysonics]

Thanks !

Is Pin 1 the plate of the 1st stage and Pin 7 the plate of the 2nd stage ?

 

[Khron]

Thanks !

Is Pin 1 the plate of the 1st stage and Pin 7 the plate of the 2nd stage ?

No. Did you even click on that first link i posted?

 

[haysonics]

Yes, it showed the pin outs for the 12AX7 series. Unfortunately I didn't see it stating what the different pins were.

 

[Khron]

Did you click on the second link i posted, then?

 

[haysonics]

The schematic, yes, but I am a beginner and all I see are pins connected to various resistors or capacitors.

 

[Khron]

https://groupdiy.com/threads/apex-460-noise.53875/ (Apex 460 schematic)

https://www.amplifiedparts.com/tech-articles/12ax7-tube-diagram (12A_7 tube pinout)

Google is your friend

Umm... Surely counting to two is feasible? The first link, as i annotated, contains the Apex 460 schematic. That, you seemed to claim you checked out. Then i asked about the SECOND link there...

 

[haysonics]

I must be missing something. You posted 2 links, one is a thread with the schematic in the first post and the other shows the numbers/positions of the pins on a socket. I can see Pin 9 is called “base pin” so i assume that’s the ground.

 

[Khron]

I can see Pin 9 is called “base” so i assume that’s the ground.

All nine pins of the tube are clearly numbered in the second diagram there, are they not?

The term "base" is used in a mechanical sense, referring to the footprint.

Tubes have no "ground" - you can connect any pin to any point in a circuit; whether it will blow up or not is an entirely separate issue.

How about pin 1 or 7, and pin 9 respectively?

 

[haysonics]

I think i am looking in the correct section : Pin 6 = PT1 and Pin 1 = PT2
Pin 7 = GT1 and Pin 9 = HM

 

[Khron]

I think i am looking in the correct section : Pin 6 = PT1 and Pin 1 = PT2

Ok, and..?

 

[haysonics]

Pin 7 = GT1 and Pin 9 = HM

 

[Khron]

Pin 7 = GT1 and Pin 9 = HM

Aha...