[Amps] Wanted

Douglas L sparks06524 at yahoo.com
Tue Mar 23 23:28:02 EDT 2021 

If you don’t mind an oldie but goody, 
I recommend the National NCL2000.
I’ve got two of them and consider them among the best amps ever made.
They easily put out about 1300 watts on a 240v line. The power supply was built to maintain 1000 watts continuous duty. Tubes are a pair of RCA/Burle 8122 tetrodes still available new (albeit expensive).
However they show up as inexpensive surplus on ebay about once a week. The 8122 was/is used in thousands of broadcast and shipboard transmitters.

One can find good condx NCL2000’s for $600 to $800.

These days with the exorbitant rise of transmitting tube prices, availability of the tubes is probably the number one consideration.

73,
Doug/WA1TUT 

> On Mar 23, 2021, at 10:56 PM, Paul Baldock <paul at paulbaldock.com> wrote:
> 
> How about an Alpha 87A $2400
> ________________________________
> From: Amps <amps-bounces at contesting.com> on behalf of Ron Ellis <KH6DV at hawaiiantel.net>
> Sent: Tuesday, March 23, 2021 6:21:14 PM
> To: amps at contesting.com <amps at contesting.com>
> Subject: [Amps] Wanted
> 
> Does anyone on the list have a good used AL-82, 1200 or 1500 amp they are
> Willing to sell.  These things are getting hard to find. Prefer the 82 as I love
> The glow of fire bottles but would consider any AL-1200 or 1500 if not too
> Expensive.
> 
> Thanks
> Ron KH6DV
> 
> 
> Sent from Mail for Windows 10
> 
> From: amps-request at contesting.com
> Sent: Tuesday, March 23, 2021 6:00 AM
> To: amps at contesting.com
> Subject: Amps Digest, Vol 219, Issue 11
> 
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> Today's Topics:
> 
>   1. Re: QRO HF2000 tank coil Q question (gudguyham)
>   2. Re: QRO HF2000 tank coil Q question (John Keating)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 23 Mar 2021 01:24:38 +0000 (UTC)
> From: gudguyham <gudguyham at aol.com>
> To: John Keating <john.keating at outlook.com>,     Peter Voelpel
>        <dj7ww at t-online.de>,     "Amps at contesting.com" <Amps at contesting.com>
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
> Message-ID: <2105074950.2623203.1616462678906 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
> 
> Have you guys taken into consideration that the tank circuit in these amps only transform down to 200 ohms, not 50 ohms from the plate impedance? ?After the tank circuit it passes through a 4 to 1 balun which brings it down to 50 ohms.
> 
> 
> Sent from the all new AOL app for iOS
> 
> 
> On Monday, March 22, 2021, 2:05 PM, John Keating <john.keating at outlook.com> wrote:
> 
> Thanks Peter. I calculate a Q of 7 to 8 for the stock design mentioned in the previous email.
> 
> There are still a fair number of these amps in use, I wondered if others had similar experience.
> 
> I considered redesigning for higher Q but the modifications to the entire tank circuit would be extensive. Again, I wondered if anyone had done such a thing.
> 
> 73, John
> 
> -----Original Message-----
> From: Peter Voelpel [mailto:dj7ww at t-online.de]
> Sent: Monday, March 22, 2021 10:52 AM
> To: 'John Keating'; Amps at contesting.com
> Subject: RE: [Amps] QRO HF2000 tank coil Q question
> 
> I used stacks of T225-2 for a mobile antenna loading coil on 40m.
> Measured Q was around 400.
> Toroid coils with taps, which no good idea anyway, will have much lower Q.
> As part of a pi network for 160m in the 2KW out class only T400 was not
> getting too hot, stacks of T300 still overheated in RTTY.
> 
> 73
> Peter
> 
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of John Keating
> Sent: Montag, 22. M?rz 2021 17:23
> To: Amps at contesting.com
> Subject: [Amps] QRO HF2000 tank coil Q question
> 
> Wondering if anyone can provide the specs on the low band tank coil for a
> QRO HF2000.
> 
> It appears to be a stack of two red-mix T225A-2 iron powder toroids, with a
> total of 25 turns, and taps for 40M at the 7th turn, and for 80M at the 13th
> turn.
> 
> Also wondering if anyone else notices how hot it gets on 160m.
> 
> 73, John
> AI6LY
> 
> _______________________________________________
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> 
> 
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 23 Mar 2021 01:28:30 +0000
> From: John Keating <john.keating at outlook.com>
> To: gudguyham <gudguyham at aol.com>, Peter Voelpel <dj7ww at t-online.de>,
>        "Amps at contesting.com" <Amps at contesting.com>
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
> Message-ID:
>        <BYAPR04MB39278776F13EA293352AC6488A649 at BYAPR04MB3927.namprd04.prod.outlook.com>
> 
> Content-Type: text/plain; charset="utf-8"
> 
> yes I took that into consideration for the calculations.
> 
> From: gudguyham [mailto:gudguyham at aol.com]
> Sent: Monday, March 22, 2021 18:25 PM
> To: John Keating; Peter Voelpel; Amps at contesting.com
> Subject: Re: [Amps] QRO HF2000 tank coil Q question
> 
> Have you guys taken into consideration that the tank circuit in these amps only transform down to 200 ohms, not 50 ohms from the plate impedance?  After the tank circuit it passes through a 4 to 1 balun which brings it down to 50 ohms.
> 
> 
> Sent from the all new AOL app for iOS<https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661>
> 
> On Monday, March 22, 2021, 2:05 PM, John Keating <john.keating at outlook.com> wrote:
> Thanks Peter. I calculate a Q of 7 to 8 for the stock design mentioned in the previous email.
> 
> There are still a fair number of these amps in use, I wondered if others had similar experience.
> 
> I considered redesigning for higher Q but the modifications to the entire tank circuit would be extensive. Again, I wondered if anyone had done such a thing.
> 
> 73, John
> 
> -----Original Message-----
> From: Peter Voelpel [mailto:dj7ww at t-online.de<mailto:dj7ww at t-online.de>]
> Sent: Monday, March 22, 2021 10:52 AM
> To: 'John Keating'; Amps at contesting.com<mailto:Amps at contesting.com>
> Subject: RE: [Amps] QRO HF2000 tank coil Q question
> 
> I used stacks of T225-2 for a mobile antenna loading coil on 40m.
> Measured Q was around 400.
> Toroid coils with taps, which no good idea anyway, will have much lower Q.
> As part of a pi network for 160m in the 2KW out class only T400 was not
> getting too hot, stacks of T300 still overheated in RTTY.
> 
> 73
> Peter
> 
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com<mailto:amps-bounces at contesting.com>] On Behalf Of John Keating
> Sent: Montag, 22. M?rz 2021 17:23
> To: Amps at contesting.com<mailto:Amps at contesting.com>
> Subject: [Amps] QRO HF2000 tank coil Q question
> 
> Wondering if anyone can provide the specs on the low band tank coil for a
> QRO HF2000.
> 
> It appears to be a stack of two red-mix T225A-2 iron powder toroids, with a
> total of 25 turns, and taps for 40M at the 7th turn, and for 80M at the 13th
> turn.
> 
> Also wondering if anyone else notices how hot it gets on 160m.
> 
> 73, John
> AI6LY
> 
> _______________________________________________
> Amps mailing list
> Amps at contesting.com<mailto:Amps at contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
> 
> _______________________________________________
> Amps mailing list
> Amps at contesting.com<mailto:Amps at contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
> 
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> 
> Subject: Digest Footer
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> ------------------------------
> 
> End of Amps Digest, Vol 219, Issue 11
> *************************************
> 
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