RE: RH84 amplifier

Posted by Tre' (P) on July 26, 2015 at 08:44:39

In Reply to: RH84 amplifier posted by krankkall on July 25, 2015 at 19:01:14:

There is two forms of feedback employed in the RH84 SE amplifier.

The plate to plate connection and the lack of a cathode bypass cap on the 12at7.

It also helps a lot that the el84 needs very little input voltage swing.

One look at the plate curves (page 3) and you will see that without feedback the 12at7 would be very non-linear trying to supply 140 volts peak to peak to, let's say, a 300b.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

12at7 plate curves (Open in New Window)

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Follow Ups Full Thread

Topic - Why aren't 12AT7s as loved as the other 12A_7 tubes. - Mechans 12:41:50 07/25/15 (14)

Heck if I know, but my preamp uses 12AT7s and 12AU7s in the line stage - David S. 14:02:04 07/29/15 (0)

They just don't work as hard as 12AX7's - Bambi B 20:08:53 07/26/15 (0)

Shhhh..Let's keep it down low - Jon L 10:27:13 07/26/15 (1)

RE: Shhhh..Let's keep it down low - Orchardist 14:47:12 07/26/15 (0)

Why aren't 12AT7s as loved as the other 12A_7 tubes. - mlee 07:29:15 07/26/15 (0)

RE: Why aren't 12AT7s as loved as the other 12A_7 tubes. - Eli Duttman 16:40:08 07/25/15 (4)

RE: Why aren't 12AT7s as loved as the other 12A_7 tubes. - Jim McShane 12:42:46 07/26/15 (0)

RH84 amplifier - krankkall 19:01:14 07/25/15 (1)

RE: RH84 amplifier - Tre' 08:44:39 07/26/15 (0)

Huh? They sound just fine in my SET amps (nt) - Byrd69 18:02:08 07/25/15 (0)

RE: Why aren't 12AT7s as loved as the other 12A_7 tubes. - CV4109 15:28:20 07/25/15 (3)

RE: Why aren't 12AT7s as loved as the other 12A_7 tubes. - DAK 23:56:24 07/25/15 (1)

RE: Why aren't 12AT7s as loved as the other 12A_7 tubes. - SETdude 06:45:45 07/26/15 (0)

mil spec triple mica Sylvania 12AT7WA - FenderLover 18:40:51 07/25/15 (0)

Follow Ups

RE: RH84 amplifier - Tre' 08:44:39 07/26/15 (0)

RE: RH84 amplifier

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