RE: I am shocked!

Posted by drlowmu (M) on July 21, 2012 at 18:05:55

In Reply to: I am shocked! posted by jedrider on July 21, 2012 at 16:31:58:

Some random ideas I have :

Q1) Were you measuring the Rks in circuit, or, did you lift one leg of them ??

Q2) What was the wattage rating (and type) of Rk you use in that position??

What is the typical VDC across the tube ( P-K ), and the typical current drawn by the EL-34s? Maybe, if its burning up Rks, the tubes are running near maximum plate dissipations, and causing premature failure of the Finals tubes and associated Rks.

MAYBE you should simply run the Finals more conservatively, AND use a better and higher wattage stable Rk under each tube ?? Perhaps a Mills MRA-5 is usable as a 10 Ohm Rk.

I do NOT suggest you mess with batteries or added auto bias circuits, just keep it a simple, well thought out and well executed circuit.

Jeff Medwin

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - I am shocked! - jedrider 16:31:58 07/21/12 (24)

RE: I am shocked! - griboon 17:00:52 08/13/12 (0)

Follow-up! - jedrider 11:32:59 08/13/12 (0)

Solution in sight! - jedrider 22:40:28 07/21/12 (12)

RE: Solution in sight! - drlowmu 23:01:50 07/21/12 (11)

Not a Happy Ending - jedrider 16:27:15 07/22/12 (7)

Sorry to hear it - 1973shovel 17:11:22 07/22/12 (5)

I'm looking for a Variac now - jedrider 07:48:11 07/24/12 (4)

RE: I'm looking for a Variac now - drlowmu 19:17:26 07/24/12 (3)

Calm down - jedrider 07:09:12 07/25/12 (2)

RE: Calm down - Tre' 19:30:27 07/26/12 (0)

Calmed - drlowmu 16:05:20 07/25/12 (0)

Sorry, but the fat lady ain't yet sung...... - drlowmu 17:03:27 07/22/12 (0)

RE: Solution in sight! - Jim McShane 11:21:59 07/22/12 (2)

RE: Solution in sight! - drlowmu 12:36:21 07/22/12 (1)

RE: Solution in sight! - Jim McShane 13:35:59 07/22/12 (0)

RE: I am shocked! - drlowmu 18:05:55 07/21/12 (2)

RE: I am shocked! - jedrider 18:42:34 07/21/12 (1)

Lift a LEG !!!@!!!!@!!! - drlowmu 18:52:31 07/21/12 (0)

RE: I am shocked! - Chris O 17:12:17 07/21/12 (5)

RE: I am shocked! - Jim McShane 11:26:39 07/22/12 (4)

RE: "a 1 watt film resistor should do quite well" - 1973shovel 12:29:16 07/22/12 (3)

RE: "a 1 watt film resistor should do quite well" - TimFox 12:30:37 07/26/12 (0)

RE: "a 1 watt film resistor should do quite well" - Jim McShane 13:35:08 07/22/12 (1)

RE: "Put a scope probe on the cathode pin of the power tube " - 1973shovel 13:59:03 07/22/12 (0)

Follow Ups

RE: I am shocked! - drlowmu 18:05:55 07/21/12 (2)

RE: I am shocked! - jedrider 18:42:34 07/21/12 (1)

Lift a LEG !!!@!!!!@!!! - drlowmu 18:52:31 07/21/12 (0)

RE: I am shocked!

Post a Message!