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141. Re: [Amps] Wire (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 28 Jul 2008 08:19:44 -0700
Yes, but how much heat depends on the design and quality of the balun -- the number of turns, the core material -- and the operating frequency (again, the core material). The use of coax rated for hi
/archives//html/Amps/2008-07/msg00321.html (8,339 bytes)

142. Re: [Amps] Wire (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 28 Jul 2008 11:04:47 -0700
Because they are badly designed, and thus don't sufficiently limit the common mode current! Do any of them specify their common mode impedance vs. frequency? Voltage baluns are TRANSFORMERS, not chok
/archives//html/Amps/2008-07/msg00339.html (8,749 bytes)

143. Re: [RFI] [Amps] So-Called Utility "Smart Meters" (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 12 Aug 2008 10:03:53 -0700
I suggest that you do what I have done for at least 15 years for both my power and heating fuel -- generate a spreadsheet with the information that comes on your monthly bill and study the trends. Yo
/archives//html/Amps/2008-08/msg00067.html (8,748 bytes)

144. [Amps] Fan for Ten Tec Titan (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 04 Sep 2008 09:38:06 -0700
The fan in the oldest of my three Titan 425s (the original Titan) is a lot noisier than the others, so I'm thinking of a replacement. Does anyone know of a part number that might replace it? 73, Jim
/archives//html/Amps/2008-09/msg00014.html (6,481 bytes)

145. Re: [Amps] Titan fan (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 06 Sep 2008 11:11:01 -0700
I started this several days ago. I have three Titan 425s. The fan in one is much noisier than the others. Thanks to all for the thoughtful and detailed advice. 73, Jim _______________________________
/archives//html/Amps/2008-09/msg00029.html (7,042 bytes)

146. Re: [Amps] 234v - to convert or not? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 14 Sep 2008 21:21:04 -0700
That's also a symptom of one or more bad filter caps in the HV string. Usually there are 8-16 of them in series, with resistors across them to equalize the voltage across them. It's not uncommon for
/archives//html/Amps/2008-09/msg00136.html (8,634 bytes)

147. Re: [Amps] 234v - to convert or not? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 15 Sep 2008 10:00:17 -0700
In the grand scheme of things, the power to run a legal-limit ham amplifier is not a lot of current at 240 volts. Here in the US, it's common for homes to have that much load in the form of a couple
/archives//html/Amps/2008-09/msg00143.html (8,527 bytes)

148. Re: [Amps] 180 ø Phase SHifter Off Topic (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 30 Oct 2008 12:27:51 -0700
Do you mean a POLARITY inverter or PHASE shifter? They are VERY different. PHASE is a function of frequency, while polarity is not. Polarity is nothing more than turning the waveform upside down at A
/archives//html/Amps/2008-10/msg00145.html (7,670 bytes)

149. Re: [Amps] coax length between transceiver and amplifier (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 03 Nov 2008 08:04:52 -0800
Except on receive, if the preamp is at the RX. If the preamp is between the antenna and the power amp, I agree that loss between the transmitter and the power amp doesn't matter. Shielding should not
/archives//html/Amps/2008-11/msg00018.html (7,605 bytes)

150. Re: [Amps] PROBLEM WITH HUM (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 10 Nov 2008 10:52:13 -0800
audio..I key the radio in SSB with the amp in line but not keyed and I get this hum and its coming from the filament transformer..I opened it up and disconnected the filament transformer then again k
/archives//html/Amps/2008-11/msg00096.html (8,334 bytes)

151. Re: [Amps] PROBLEM WITH HUM (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 10 Nov 2008 13:23:32 -0800
Possible hum problems are associated with improper wiring of the PRIMARY of the transformer. You comments apply to the SECONDARY of the transformer, and are not relevant to this discussion. 73, Jim K
/archives//html/Amps/2008-11/msg00099.html (7,580 bytes)

152. Re: [Amps] Vacuum Relay Issues (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Mon, 01 Dec 2008 09:52:23 -0800
Hi Tom, This is a common failure mode. I have the same problem with the relays in my Ten Tec Titan amps. Original equipment was Jennings, I've used some Jennings parts that are supposedly new pulls f
/archives//html/Amps/2008-12/msg00013.html (7,175 bytes)

153. Re: [Amps] Vacuum Relays (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 02 Dec 2008 08:59:49 -0800
I don't know that amp, but the relays in the Ten Tec 425 can be changed out in about an hour. A bit longer if you're doing it for the first time. Gigavac makes direct replacements for Jennings and Ki
/archives//html/Amps/2008-12/msg00039.html (7,304 bytes)

154. Re: [Amps] Vacuum Relays (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 03 Dec 2008 10:17:03 -0800
Thanks Dave. That does shed some light. My Titans all came with RJ1As, and as they die, I've replaced them with either RJ1A pulls or Gigavac equivalent. Are you aware that I have a 90% Titan 425 sche
/archives//html/Amps/2008-12/msg00073.html (7,640 bytes)

155. Re: [Amps] rx noise? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sun, 07 Dec 2008 15:43:50 -0800
A T/R relay going south seems like a possibility. I'd give it a go calling CQ on 80 or 160 during the day with full QSK. If it's a relay, that ought to make it stop being intermittent. A common failu
/archives//html/Amps/2008-12/msg00155.html (8,108 bytes)

156. Re: [Amps] Closure on the Vacuum Relays, Plus... (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 09 Dec 2008 07:28:42 -0800
On target and well said, Tom. 73, Jim K9YC _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2008-12/msg00173.html (7,080 bytes)

157. Re: [Amps] Closure on the Vacuum Relays, Plus... (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 11 Dec 2008 21:29:02 -0800
The TenTec Titan 425 has circuitry that senses RF input and won't let T/R relay drop until RF input has gone away. This prevents hot switching of the T/R relay in the power amp in this situation. Thi
/archives//html/Amps/2008-12/msg00201.html (7,885 bytes)

158. Re: [Amps] Parts for Ten Tec Amplifiers? (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Tue, 16 Dec 2008 10:32:34 -0800
Don't know about the Titan II, but the Titan I (425) uses all discrete components, most of which are pretty widely available on the surplus market, and that are pretty easy to fix. The tricky part ab
/archives//html/Amps/2008-12/msg00240.html (7,660 bytes)

159. Re: [Amps] 3CPX800A7 (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 24 Dec 2008 10:29:17 -0800
It will certainly increase the power headroom available. Using that power to safely run at the legal limit on RTTY in a contest without risk of failure is fine. Using it to exceed the legal limit is
/archives//html/Amps/2008-12/msg00317.html (7,797 bytes)

160. Re: [Amps] Tetrode Boards Grounding Scheme (score: 1)
Author: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Thu, 08 Jan 2009 11:12:08 -0800
In most interconnect wiring, the concern is NOT IR drop (or IZ drop) for the signal, but rather for NOISE current induced onto signal wiring. In general, the signal is a voltage from a low Z source w
/archives//html/Amps/2009-01/msg00066.html (8,945 bytes)

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