Re: Question and comment on tube matching

Posted by Lew (A) on April 12, 2006 at 09:01:58

In Reply to: Re: Question and comment on tube matching posted by Legendre on April 11, 2006 at 16:02:26:

I never paid much attention to it, but when I fire up the amps from cold (I don't leave them in Standby mode), the 6C33Cs "boil up" in about 5 minutes to the point where they are uncomfortable to touch at the base but not so hot around the top "nipples". After I apply LV, then they do seem to get hotter (so you cannot touch them at all) and perhaps do glow more a red-orange vs orange. I bias conservatively at 280 to 300mA per tube, depending upon my mood at the time I am doing the bias procedure (about once every 6 months). One other virtue of being able to bias each tube separately, I think, is that the tubes drift in unison. If I had previously set bias for each tube at 300mA (and I have installed 12-turn bias pots, so I can really dial it in), then all tubes will be down in bias by about same amount or not much at all after 6 months. I guess when I reach the point that a lot of adjustment upwards is needed, i.e., there is a marked downward drift in a 6-month period, that will mean the tubes are on the downward slope of their lifespan.

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

Follow Ups Full Thread

Topic - 6C33C-B & Novacron revisited - Legendre 16:50:26 04/05/06 (23)

MA240SE - Lew 08:39:04 04/10/06 (0)

Re: 6C33C-B & Novacron revisited - 6C33DG 19:01:26 04/09/06 (0)

any other Novacron photos available besides the usual Atma-Sphere pic? - Bersani 22:31:02 04/06/06 (14)

Not the greatest pic, but.... - Sue Kraft 13:46:10 04/07/06 (13)

Cool, thank you (and lucky you, as well)! (nt) - Bersani 17:49:59 04/07/06 (0)

Now who built those? - Legendre 16:01:02 04/07/06 (11)

Would you believe I did? - Sue Kraft 20:17:04 04/07/06 (10)

that explains why the output tubes are installed backwards. - lone gunmen 05:34:37 04/08/06 (9)

No wonder... - Sue Kraft 07:13:05 04/08/06 (8)

madam,you're a dumb-sh*t. - lone gunmen 13:17:26 04/08/06 (7)

Jeez.... - Mike Currie 12:55:37 04/11/06 (0)

Way uncalled for - BlackPlasticSound 22:52:11 04/08/06 (1)

I agree it was uncalled for - MIchael Samra 09:40:27 04/10/06 (0)

Now I understand why the OTL board is so dead most of the time - Sue Kraft 16:04:25 04/08/06 (3)

Not Defending the Gunslingers, but... - LineArrayNut 01:14:51 04/10/06 (1)

Re: Not Defending the Gunslingers, but... - Legendre 07:27:11 04/10/06 (0)

Thanks anyway Sue. Unfortuntely some people lack basic social skills. (nt) - Bersani 23:38:58 04/08/06 (0)

Re: 6C33C-B & Novacron revisited - chris keating 08:56:32 04/06/06 (0)

Re: 6C33C-B & Novacron revisited - morricab 04:21:45 04/06/06 (4)

Question and comment on tube matching - Lew 10:04:48 04/11/06 (3)

Re: Question and comment on tube matching - morricab 02:08:21 04/12/06 (0)

Re: Question and comment on tube matching - Legendre 16:02:26 04/11/06 (1)

Re: Question and comment on tube matching - Lew 09:01:58 04/12/06 (0)

Follow Ups

Re: Question and comment on tube matching - Lew 09:01:58 04/12/06 (0)

Re: Question and comment on tube matching

Post a Message!