Questions about Cathode Follower

Posted by akltam (A) on August 24, 2015 at 00:35:33

I am planning to build a 'Williamson' based power amp with 3 pairs of KT150 in Triode mode.

I am trying to get the design parameters right before I start to pour money into the project.

As suggested by some website (Lenardaudio), I added a cathode follower (6CG7) after the driving tube (12au7) to lower the impedance to drive the 3 pairs of KT150. (Please see the attached schematics)

As some suggested, the anode plate voltage of the 12au7 needs to be at 200-250V running at 5-6mA each section to fully utilized the potential of the tube.

As the 12au7 is direct couple to the cathode follower (6CG7), the cathode of the 6CG7 will be at 230-250V already. Thus the anode plate voltage of the 6CG7 need to be at double of that which is around 470V.

I am concern the anode plate voltage for the 6CG7 is too high at 470V.

My question is, when the tube spec said the maximum design voltage for the anode plate of 6CG7 is 300V, is that the absolute maximum, or is it the maximum voltage between the anode and the cathode ???

Alan

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Topic - Questions about Cathode Follower - akltam 00:35:33 08/24/15 (22)

RE: Questions about Cathode Follower - Al Noakes 08:19:07 08/24/15 (2)

RE: Questions about Cathode Follower - Chip647 04:51:57 08/25/15 (1)

RE: Questions about Cathode Follower - Al Noakes 06:04:38 08/25/15 (0)

Eli's suggestion... - Lew 07:45:01 08/24/15 (5)

RE: Eli's suggestion... - JKT 13:53:56 08/24/15 (4)

How does the 'button base' looks like ? - akltam 21:06:08 08/24/15 (3)

RE: How does the 'button base' looks like ? - JKT 13:14:15 08/25/15 (2)

Do you refer to height, rather than "thick"-ness? - Lew 06:34:33 08/26/15 (1)

"Button base" illustrated.... - Steve O 20:36:12 08/26/15 (0)

6BL7 / 6BX7 - Triode_Kingdom 06:36:38 08/24/15 (7)

Which Tube socket does the 6BL7 / 6BX7 use ? - akltam 07:07:26 08/24/15 (6)

Octal - Triode_Kingdom 07:30:08 08/24/15 (5)

What Bias Current should I be running the 6BL7/6BX7 ? - akltam 19:45:59 08/24/15 (4)

After more research, .... - akltam 06:38:36 08/25/15 (3)

RE: After more research, .... - Caucasian Blackplate 09:18:31 08/25/15 (2)

If I use a 6BX7 ... - akltam 02:42:43 08/26/15 (1)

RE: If I use a 6BX7 ... - PakProtector 09:05:56 08/27/15 (0)

RE: Questions about Cathode Follower - Eli Duttman 05:28:29 08/24/15 (1)

RE: Questions about Cathode Follower - drsx 20:39:25 08/24/15 (0)

RE: Questions about Cathode Follower - danlaudionut 04:34:43 08/24/15 (2)

RE: Questions about Cathode Follower - Chip647 04:47:12 08/24/15 (1)

RE: Questions about Cathode Follower - akltam 07:51:23 08/24/15 (0)

Questions about Cathode Follower

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