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References: [ +from:df3kv@t-online.de: 314 ]

Total 314 documents matching your query.

161. Re: [Amps] Martin's Comments on EB-104 Pictures (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Tue, 8 Jul 2008 22:45:21 +0200
Please verify your external links to other home brewers, most are not working 73 Peter Martin, Thanks very much for taking the time to write this detailed set of comments. We appreciate them, and wil
/archives//html/Amps/2008-07/msg00070.html (8,916 bytes)

162. Re: [Amps] A Grounded Grid biasing question (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 9 Jul 2008 20:39:41 +0200
A negative voltage source will not work for biasing at the cathode, it will do the opposite. I see the necessary (preadjusted) positive voltage reaches the cathode when the IRF540 switches through. 7
/archives//html/Amps/2008-07/msg00091.html (10,231 bytes)

163. Re: [Amps] A Grounded Grid biasing question (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Thu, 10 Jul 2008 07:19:31 +0200
Yes, that works as well with the grid lifted, but itīs much better to have it tight RF grounded and supply positive voltage to the cathode, which is done on that circuitry The positive bias voltage i
/archives//html/Amps/2008-07/msg00095.html (12,598 bytes)

164. Re: [Amps] Help with ARRL handbook design 4CX1000A 2m PA (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Mon, 21 Jul 2008 18:51:49 +0200
I built with those tubes a push-pull 2m amp many years ago, it was a quick&dirty design with efficiency at 58%. So the tubes do very well there. Is there something running hot in the output circuitry
/archives//html/Amps/2008-07/msg00190.html (8,333 bytes)

165. Re: [Amps] Bill Orr comment (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 23 Jul 2008 19:10:14 +0200
2-2.5 times the dissipation is normal. Assume 1500 out, at 70% efficiency that is 643W dissipation, 1500/643=2.33. Eimac claims 75% efficiency on their 3CX3000A7 datasheet in AB2. 73 Peter I was read
/archives//html/Amps/2008-07/msg00207.html (8,925 bytes)

166. Re: [Amps] Bill Orr comment (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 23 Jul 2008 19:54:14 +0200
The 3-500Z does it when the anode gets 4KV, otherwise its current is the limit. You are right with the 8877. It all depends on the type of cathode. 73 Üeter Depends on how much of a quack your reside
/archives//html/Amps/2008-07/msg00212.html (9,812 bytes)

167. Re: [Amps] Bill Orr comment (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 23 Jul 2008 22:39:47 +0200
Yes, feed trough power should be subtracted for the real calculation. To me it looks as Eimac did not do that on their 3CX3K datasheet. My glass envelope tubes can be driven very hard in GG without g
/archives//html/Amps/2008-07/msg00217.html (11,364 bytes)

168. Re: [Amps] cooling chimney? (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Thu, 24 Jul 2008 03:17:00 +0200
I like the use of chimneys with similar tubes for another reason as well, for protecting nearby components. In the past I experienced in one HB amp two times the desoldering of capacitor connections
/archives//html/Amps/2008-07/msg00224.html (9,904 bytes)

169. Re: [Amps] Tube sources (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Fri, 25 Jul 2008 16:29:57 +0200
Amperex stopped glass tube production. A glass factory in Northern Germany were using 4-400B tubes from them as voltage regulators for there magnetron generators. When the tubes got unavailable they
/archives//html/Amps/2008-07/msg00248.html (11,786 bytes)

170. Re: [Amps] Use of toroids in tank circuit of tube amp? (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Sun, 7 Sep 2008 03:14:46 +0200
You need to use powered iron cores. The limitation is the voltage across the windings. On a similar amplifier I used toroids for my 160m extension and split the necessary additional induction into 4
/archives//html/Amps/2008-09/msg00031.html (8,062 bytes)

171. Re: [Amps] 3-500Z glitch resistor (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Tue, 16 Sep 2008 20:30:08 +0200
Put the wire into a glass tube and fill that with sand 73 Peter --Original Message-- From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On Behalf Of Roger (K8RI) Sent: Dienstag, 1
/archives//html/Amps/2008-09/msg00157.html (10,854 bytes)

172. Re: [Amps] 3-500Z glitch resistor (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 17 Sep 2008 01:49:22 +0200
Not if you insert a string of diodes from screen voltage to B+ behind the resistor 73 Peter If I had used a fuse in series with the resistor, I would have been replacing fuses instead of the harder a
/archives//html/Amps/2008-09/msg00164.html (9,580 bytes)

173. Re: [Amps] gg amp question... (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Fri, 26 Sep 2008 21:02:18 +0200
About half of that will be right. Voltage swing is less then 2.2KV, and the conduction angle is not 360°. 73 Peter R = E/I = 2200/.4 = 5500 Ohms. Close as you're gonna get. -WB2WIK/6 --Original Messa
/archives//html/Amps/2008-09/msg00213.html (8,644 bytes)

174. Re: [Amps] HT41 (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Tue, 4 Nov 2008 19:18:14 +0100
I converted one to a pair of highĩ connected 4-125A/QB3-300 35 years ago, worked very well. The most difficult part was to make the socket holes larger, itīs a very massive chassis. I converted the p
/archives//html/Amps/2008-11/msg00027.html (7,766 bytes)

175. Re: [Amps] 3CX1500D7 quote (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Thu, 8 Jan 2009 13:22:03 +0100
I bought 10+ GS-35B at 40.-DM in 1999. Most have been given away to ham friends shortly after for their projects, others were used to convert linears. I should have bought 100 that time as well as GU
/archives//html/Amps/2009-01/msg00058.html (12,286 bytes)

176. Re: [Amps] interesting piece of kit..... (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Sun, 11 Jan 2009 01:35:39 +0100
Those Henry generators are built in many variations, that one seems to be a 13.56MHz version. I own an older 2000D for 27.12MHz which I use on 10m, in there the laoding capacitor is a vacuum variable
/archives//html/Amps/2009-01/msg00078.html (9,198 bytes)

177. Re: [Amps] GU81-M on highbands (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Sun, 11 Jan 2009 20:08:49 +0100
I donīt see anything special with the Pi-net circuit. It is common practise to use fixed anode capacitors (including internal C) when using a roller inductor, in that case to have a separate 10m coil
/archives//html/Amps/2009-01/msg00086.html (11,578 bytes)

178. Re: [Amps] 3-500zs to 8877 (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 21 Jan 2009 17:01:30 +0100
Both tubes need 5V filament voltage but th 3-500Z wants more current 73 Peter A good example of the change you would like to achieve is available by viewing the Ameritron series of amps. Specifically
/archives//html/Amps/2009-01/msg00202.html (7,709 bytes)

179. Re: [Amps] 3-500zs to 8877 (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 21 Jan 2009 19:35:23 +0100
The table in the Eimac power grid tubes booklet shows the better figure for the 3-5ooZ. 73 Peter --Original Message-- From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On Behalf
/archives//html/Amps/2009-01/msg00213.html (13,411 bytes)

180. Re: [Amps] Input Z for 2xGI7b (score: 1)
Author: "Peter Voelpel" <df3kv@t-online.de>
Date: Mon, 26 Jan 2009 14:42:09 +0100
The original datasheet says S=23mA/V +/- 3mA/V, therefore two tubes should have an input resistance of 19-25 ohm in grounded grid 73 Peter Gentlemen, What's the concensus on the input resistance of a
/archives//html/Amps/2009-01/msg00293.html (7,418 bytes)

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