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Total 14 documents matching your query.

1. [Amps] What tube? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 28 Jan 2015 14:00:46 +0000
A question to all those of you who have used many different tubes: What tube(s) would you recommend for a legal limit HF amplifier, to get as close as possible to the following goals: - Class AB2 ope
/archives//html/Amps/2015-01/msg00338.html (7,483 bytes)

2. Re: [Amps] What tube? (score: 1)
Author: Larry <larry@w7iuv.com>
Date: Wed, 28 Jan 2015 08:12:48 -0800
AS far as I know, there is only one tube(s) that meet your requirements; a pair of 3-500Zs. If you drop the "instant-on" requirement, there are quite a few other possibilities. One other possibility
/archives//html/Amps/2015-01/msg00342.html (8,854 bytes)

3. Re: [Amps] What tube? (score: 1)
Author: "Mike McCarthy, W1NR" <lists@w1nr.net>
Date: Wed, 28 Jan 2015 11:48:43 -0500
I agree. The 3-500 is about the only one to meet those requirements. I would even go with 3 of them in parallel to allow for high duty cycles like RTTY. Conduction and/or water cooled tubes will brea
/archives//html/Amps/2015-01/msg00344.html (9,320 bytes)

4. Re: [Amps] What tube? (score: 1)
Author: "Carl" <km1h@jeremy.qozzy.com>
Date: Wed, 28 Jan 2015 14:03:27 -0500
The 4-400 in GG have less gain than a 3-500 and a pair is usually good for 1000W in a full GG SB-220 thru 10M at 100W drive unless they are tired pulls. I converted an ISM amp with a pair of them to
/archives//html/Amps/2015-01/msg00348.html (10,241 bytes)

5. Re: [Amps] What tube? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 29 Jan 2015 16:58:12 +0000
Well, I got suggestions for three different tubes. All of them being directly heated glass bottles, which makes a lot of sense given my requirements. I don't think I will ever actually build that amp
/archives//html/Amps/2015-01/msg00365.html (14,895 bytes)

6. Re: [Amps] What tube? (score: 1)
Author: Gerald Williamson via Amps <amps@contesting.com>
Date: Thu, 29 Jan 2015 12:36:35 -0500
Manfred, you can be sure that tube life is adversely affected by frequent on/off cycles of the filament. One of the current tube manufacturers (Burle I think) has a paper on his website that suggests
/archives//html/Amps/2015-01/msg00366.html (15,757 bytes)

7. Re: [Amps] What tube? (score: 1)
Author: Mike Waters <mikewate@gmail.com>
Date: Thu, 29 Jan 2015 11:55:52 -0600
That's true. See www.w0btu.com/miller-larson_effect.html 73, Mike www.w0btu.com _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailm
/archives//html/Amps/2015-01/msg00367.html (7,559 bytes)

8. Re: [Amps] What tube? (score: 1)
Author: "Fuqua, Bill L" <wlfuqu00@uky.edu>
Date: Thu, 29 Jan 2015 22:06:19 +0000
We had a guy in our club that believed that tubes would last longer if you never turned them off. Naturally, the tubes were completely flat after he had not used the amplifier over a period of time.
/archives//html/Amps/2015-01/msg00368.html (8,112 bytes)

9. Re: [Amps] What tube? (score: 1)
Author: Gerald Williamson via Amps <amps@contesting.com>
Date: Thu, 29 Jan 2015 17:19:46 -0500
Bill, he had the right idea; except they last longer if you never turn them on! 73, Gerald K5GW In a message dated 1/29/2015 2:08:25 P.M. Pacific Standard Time, wlfuqu00@uky.edu writes: We had a guy
/archives//html/Amps/2015-01/msg00369.html (7,956 bytes)

10. Re: [Amps] What tube? (score: 1)
Author: "Carl" <km1h@jeremy.qozzy.com>
Date: Thu, 29 Jan 2015 18:51:52 -0500
If you use care in selecting the filament transformer it can be self current limiting. The one in the SB-220 is a good example. Many HB and commercial amps start off with a "robust" transformer capab
/archives//html/Amps/2015-01/msg00370.html (18,456 bytes)

11. Re: [Amps] What tube? (score: 1)
Author: "Carl" <km1h@jeremy.qozzy.com>
Date: Thu, 29 Jan 2015 18:52:39 -0500
The 4-400 and GU-81M can both be run in GG. In a SB-220 with100W of drive you can expect 1000W due to a bit lower gain than the 3-500Z. Crank up the voltage at the same 100W and 1500W is likely attai
/archives//html/Amps/2015-01/msg00371.html (17,660 bytes)

12. Re: [Amps] What tube? (score: 1)
Author: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Thu, 29 Jan 2015 23:37:45 -0500
Not necessarily. Particularly older glass bottles like the 813 and glass to metal like the PL172 which go gassy with little or no use. Good 813s are gettiong harder to find and I think PL172s are rar
/archives//html/Amps/2015-01/msg00376.html (9,095 bytes)

13. Re: [Amps] What tube? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 30 Jan 2015 16:19:26 +0000
you can be sure that tube life is adversely affected by frequent on/off cycles of the filament. Well, then it seems to be a bad idea to do so. Which puts tubes some more points behind solid state dev
/archives//html/Amps/2015-01/msg00377.html (17,928 bytes)

14. Re: [Amps] What tube? (score: 1)
Author: "Carl" <km1h@jeremy.qozzy.com>
Date: Fri, 30 Jan 2015 17:23:46 -0500
Old 813's, 4-400A, and most any other post WW2 glass tube may benefit from the same regettring process as the 3-500, 572B, etc. Ive recovered many 211/VT4's, 809, 810, 8000, 8005, 813, 4-250/400's, a
/archives//html/Amps/2015-01/msg00379.html (10,656 bytes)

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