As far as the 50 volt power supply, You'd need about 50 amps for a for a 1,000
watt amplifier. (Class A/B efficiency). I am looking for a similar supply, but
I'm leery of all the pin-outs. Most require a feedback loop for sampling the
voltage, a 5 volt status line, and a remote on/off line.
I can never find any real documentation for these server supplies. Meanwell in
China builds supplies that will work, but they are expensive.
http://www.trcelectronics.com/Meanwell/power-supply-pfc-rsp2000.shtml It would
be ok to parallel two supplies to get the current from 2 smaller supplies, but
I would put rectifiers after the output and before i combine them.
Bob NM1Z
Director of Engineering
WOAY-TV-ABC
Bluefield/Beckley/Oak Hill, WV market
> From: amps-request@contesting.com
> Subject: Amps Digest, Vol 135, Issue 32
> To: amps@contesting.com
> Date: Wed, 26 Mar 2014 08:24:10 -0400
>
> Send Amps mailing list submissions to
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>
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> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Amps digest..."
>
>
> Today's Topics:
>
> 1. HV limit for rfc-3 choke? (Rich Hallman - N7TR)
> 2. Re: HV limit for rfc-3 choke? (Carl)
> 3. Re: HV limit for rfc-3 choke? (Alek Petkovic)
> 4. Re: HV limit for rfc-3 choke? (peter chadwick)
> 5. Re: More on Toroidal Tank Circuit Issues (Jim W7RY)
> 6. Re: HV limit for rfc-3 choke? (Leigh Turner)
> 7. 50 V high current power supplies (David Kirkby)
> 8. Re: 50 V high current power supplies (Chris Wilson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 25 Mar 2014 18:06:43 +0000
> From: Rich Hallman - N7TR <rich@n7tr.com>
> To: amp reflector <amps@contesting.com>
> Subject: [Amps] HV limit for rfc-3 choke?
> Message-ID: <297546FA-27BB-4EDB-A74C-FDFB6920C02C@n7tr.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Will the rfc-3 choke work at 5kv? I know they say 4kv, but wanted to know
> if others are using it at higher voltages?
>
> Thanks.... Rich N7TR
>
> ------------------------------
>
> Message: 2
> Date: Tue, 25 Mar 2014 16:30:39 -0400
> From: "Carl" <km1h@jeremy.mv.com>
> To: "Rich Hallman - N7TR" <rich@n7tr.com>, "amp reflector"
> <amps@contesting.com>
> Subject: Re: [Amps] HV limit for rfc-3 choke?
> Message-ID: <AA2F4AEC6CE94F70BF2EB3AEDE78C515@computer1>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> I know people using them at 5KV from a 4-1000 to 3CX3000; they appear to
> hold up but I wouldnt want to experiment on RTTY with the 3X3 or bigger..
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Rich Hallman - N7TR" <rich@n7tr.com>
> To: "amp reflector" <amps@contesting.com>
> Sent: Tuesday, March 25, 2014 2:06 PM
> Subject: [Amps] HV limit for rfc-3 choke?
>
>
> > Will the rfc-3 choke work at 5kv? I know they say 4kv, but wanted to
> > know if others are using it at higher voltages?
> >
> > Thanks.... Rich N7TR
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 2014.0.4354 / Virus Database: 3722/7241 - Release Date: 03/24/14
> >
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 26 Mar 2014 06:12:07 +0800
> From: Alek Petkovic <vk6apk@bigpond.com>
> Cc: amp reflector <amps@contesting.com>
> Subject: Re: [Amps] HV limit for rfc-3 choke?
> Message-ID: <5331FF37.2070809@bigpond.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Dunno what 'the rfc-3 choke' is but if it is the Ameritron plate
> choke,that we all use in our homebrew amps, I'm running it at 6kV in a
> YC-156 amp. I never knew that it had a limit/rating on it. Sometimes,
> ignorance is bliss.
>
> Alek. VK6APK
>
> On 26/03/2014 4:30 AM, Carl wrote:
> > I know people using them at 5KV from a 4-1000 to 3CX3000; they appear
> > to hold up but I wouldnt want to experiment on RTTY with the 3X3 or
> > bigger..
> >
> > Carl
> > KM1H
> >
> >
> > ----- Original Message ----- From: "Rich Hallman - N7TR" <rich@n7tr.com>
> > To: "amp reflector" <amps@contesting.com>
> > Sent: Tuesday, March 25, 2014 2:06 PM
> > Subject: [Amps] HV limit for rfc-3 choke?
> >
> >
> >> Will the rfc-3 choke work at 5kv? I know they say 4kv, but wanted
> >> to know if others are using it at higher voltages?
> >>
> >> Thanks.... Rich N7TR
> >> _______________________________________________
> >> Amps mailing list
> >> Amps@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/amps
> >>
> >>
> >> -----
> >> No virus found in this message.
> >> Checked by AVG - www.avg.com
> >> Version: 2014.0.4354 / Virus Database: 3722/7241 - Release Date:
> >> 03/24/14
> >>
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
>
> --
> http://www.qrz.com/db/vk6apk
> http://www.qrz.com/db/vk6ap
>
> Family Businesses:
> Petkovic Air& Gas. petkovicag@bigpond.com
> SP Electrical. www.spelectrical.net.au
> Hampers by Hand. www.facebook.com/hampersbyhand
>
>
> ---
> This email is free from viruses and malware because avast! Antivirus
> protection is active.
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>
>
> ------------------------------
>
> Message: 4
> Date: Tue, 25 Mar 2014 23:18:14 +0100
> From: peter chadwick <g8on@fsmail.net>
> To: Carl <km1h@jeremy.mv.com>, Rich Hallman - N7TR <rich@n7tr.com>,
> amp reflector <amps@contesting.com>
> Subject: Re: [Amps] HV limit for rfc-3 choke?
> Message-ID: <10486968.28311395785894770.JavaMail.www@wwinf3719>
> Content-Type: text/plain; charset=UTF-8
>
> Figure it this way:
>
> Suppose you have 5kV DC and a plate swing of 8kV p-p or 2800 RMS. 225
> microhenries is 2545 ohms at 1.8 MHz so the RF current in the choke is 1.1
> amps, in addition to the DC. If Q = 100, R = 25 ohms and the power loss in
> the choke becomes 30 watts. That 1.1 amps needs a low impedance ground
> return, so that means something of the order of maybe 5nF to ground. Larger
> values can get too inductive on the higher bands... Even then, 5nF is 17 ohms
> at 1.8 MHz, so there will be about 20 volts of RF at the base of the choke.
> That means you need another choke and capacitor to keep RF away from the HV
> electrolytics.
>
> I recently published an article in the journal of the Vintage and Military
> Amateur Radio Society on this: I can send a copy if anyone has any interest.
>
> 73
>
> Peter G3RZP
> ========================================
> Message Received: Mar 25 2014, 08:30 PM
> From: "Carl" <km1h@jeremy.mv.com>
> To: "Rich Hallman - N7TR" <rich@n7tr.com>, "amp reflector"
> <amps@contesting.com>
> Cc:
> Subject: Re: [Amps] HV limit for rfc-3 choke?
>
> I know people using them at 5KV from a 4-1000 to 3CX3000; they appear to
> hold up but I wouldnt want to experiment on RTTY with the 3X3 or bigger..
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Rich Hallman - N7TR" <rich@n7tr.com>
> To: "amp reflector" <amps@contesting.com>
> Sent: Tuesday, March 25, 2014 2:06 PM
> Subject: [Amps] HV limit for rfc-3 choke?
>
>
> > Will the rfc-3 choke work at 5kv? I know they say 4kv, but wanted to
> > know if others are using it at higher voltages?
> >
> > Thanks.... Rich N7TR
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 2014.0.4354 / Virus Database: 3722/7241 - Release Date: 03/24/14
> >
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 25 Mar 2014 21:36:08 -0700
> From: "Jim W7RY" <w7ry@centurytel.net>
> To: <Undisclosed-Recipient:;>
> Cc: AMPS <amps@contesting.com>
> Subject: Re: [Amps] More on Toroidal Tank Circuit Issues
> Message-ID: <2B631DB2453D46F58E5DA4BF4CDA7380@JimsLaptop>
> Content-Type: text/plain; format=flowed; charset="UTF-8";
> reply-type=original
>
> So here is the real fix!
>
> I removed the 80 and 160 meter toroids all together. Installed a 2" dia X
> 3.5" long ceramic coil with 42 turns of #14 wire and hooked it to the end of
> the 40 meter coil. The new coil is perpendicular to the 20-40 meter coil.
>
> Works perfectly! No more 10 meter heating! And on 80 meters, with lots of
> keydown at 1600 watts out, the coil gets to about 125 degrees F, and on 160
> a little less. But I normally don?t run RTTY on 160 meters. As of yet, all
> RTTY contests are on 80-10.
>
> The best bet will be to find a ceramic coil or just the coil-form that I can
> wind with #12 or #10 wire. 10 is probably a bit too big. I guess I could
> wind 80 meters with #10 and 160 meters with #12. I really want to stay with
> a ceramic coil-form to keep it from deforming like a air-dux coil would.
>
> I know Carl has a ceramic form on the auction site but it too is wound with
> #14 wire.
>
> Anyone have a 2" (and it must not be more than 2-1/4" X 5 or 6 inch long
> ceramic coil-form with grooves for winding? It has to have at least 36
> grooves for 36 turns of wire.
>
> This has been an interesting experiment to say the least!
>
> Thanks all
> 73
> Jim W7RY
>
>
> -----Original Message-----
> From: Jim W7RY
> Sent: Saturday, March 22, 2014 1:25 PM
> To: Dan Hearn
> Cc: AMPS
> Subject: Re: [Amps] More on Toroidal Tank Circuit Issues
>
> So I used the measurement technique from Tom W8JI that he has on his site
> and found that the 160 meter toroid was certainly resonate on 10 meters! No
> matter what I did. Sure, I could move my hand around the toroid and get the
> the lamp to dim and sometimes go out. But there didn?t seem to be any place
> moving the windings that would help.
> http://www.w8ji.com/rf_plate_choke.htm
>
>
> So..... I made a center tap on the 160 meter toroid and simply shorted it to
> one end with a normally closed vacuum relay. I open the relay only on 160
> meters.
>
> See here:
> http://s900.photobucket.com/user/w7ry/media/8877%20Amplifier/IMG_0250_zps17bca129.jpg.html?sort=3&o=0
>
> Seems to work just great. No arcing or sparking. As you can see, the leads
> are pretty long and the relay is just taped to the Plexiglas. I used the
> bench power supply to energize the relay on 160. There was no interaction
> with anything. Even had the lid off when testing 160 meters.
>
> The toroid seems to run perfectly cool (about a 10 degree temperature rise
> on 10 meters measuring with my Fluke IR thermometer) when operating on all
> bands. Tuning seemed better and more power output with less drive and lower
> plate current for the same output power (1600 watts) on 10 meters just like
> removing the toroid all together.
>
> I'm going to move the 160 meter toroid back to where it was, and move it
> further from the load vacuum cap. If I had it to do over again, I would have
> mounted the caps closer to the outside walls to give me more room to work
> between them.
>
> I?ll also have to wire up the relay to energize on 160 meters. Rather than
> tie into the tuned input switching, I?ll just put another switch contact
> between the front panel and the sub panel.
>
>
> 73
> Jim W7RY
>
>
>
>
>
> From: Dan Hearn
> Sent: Friday, March 21, 2014 5:47 PM
> To: Jim W7RY
> Cc: AMPS
> Subject: Re: [Amps] More on Toroidal Tank Circuit Issues
>
> Jim, I would try a small air wound coil similar to what you would use in a
> parasitic suppressor in series with the toroid, maybe in the lead to the
> switch.
>
>
> Dan, N5AR
>
>
>
>
> On Fri, Mar 21, 2014 at 4:46 PM, Jim W7RY <w7ry@centurytel.net> wrote:
>
> Both leads are shored by the band switch when on 10 meters guys.
> Interesting that 3 of you came up with the same possibility...
>
> Not sure where to put the capacitor if both leads are shorted together.
> Perhaps I could center tap the toroid (bare the Teflon wire) and solder a
> cap from the center tap to one of the output leads.
>
> I removed the toroid and the major heat in the 3 turns of wire is where
> the winding is within 1/4 inch of the vacuum loading cap. Which is probably
> to close.
> See:
> http://s900.photobucket.com/user/w7ry/media/8877%20Amplifier/P1010217.jpg.html?sort=3&o=16
>
> I was simply going to move it away from the loading cap and see what
> happens. I was also thinking of install a wire coil. I have a ceramic coil
> form that would work. 30 turns, 2?dia 3.5? long which is 20uH. I have room
> to mount this.
>
> Thanks all!
> 73
> Jim W7RY
>
>
> From: Dan Hearn
> Sent: Friday, March 21, 2014 3:02 PM
> To: Jim W7RY
> Cc: AMPS
> Subject: Re: [Amps] More on Toroidal Tank Circuit Issues
>
> Jim, I think your 160 toroid when shorted is self resonant with its
> distributed capacitance on 10m. You might be able to solve this by putting
> a small cap across the 160 m toroid to move its self resonance.
>
>
> 73, Dan, N5AR
>
>
>
>
> On Fri, Mar 21, 2014 at 1:08 PM, Jim W7RY <w7ry@centurytel.net> wrote:
>
> I may have to eat some crow here about using dedicated toroids on 160
> and 80 meters...
>
> I built an 8877 amplifier based on the K8RA (SK) 3CX1500D7 amplifier.
> http://www.k8ra.com/index_049.htm
>
> Mine is shown here:
> http://s900.photobucket.com/user/w7ry/media/8877%20Amplifier/DSC_0037.jpg.html?sort=3&o=47
>
> And here:
> http://s900.photobucket.com/user/w7ry/media/8877%20Amplifier/P1010225.jpg.html?sort=3&o=13
>
> The lower toroid is 160 only and the upper one is 80 meters only (with
> 10,15,20 and 40 coils added in of course).
>
> I?m using a shorting band switch 6 position.
>
>
> On 10 meters, the 160 meter toroid (lower one) gets so hot, the
> fiberglass tape has turned brown, and the Teflon wire is melting the
> Plexiglas that the toroid's are mounted on.
>
> I know all about trying to use a tapped toroid for multiple bands is
> wrong (except on the L coil of the Pi-L circuit, and see my postings about
> the Commander HF-2500 and K1TTT?s pictures of same) but WHY is the 160 meter
> toroid getting so hot when using 10 meters? It's mounted very close to the
> loading vacuum capacitor is the only thing that I can think of. But the
> weird part, is that this just started. During all of the testing, there was
> no problem, but now, its really getting HOT!
>
> When testing, I had the top cover off of the amplifier, now that I?m
> using it, the top cover is on. I?m going to try the test again with the top
> off and see what happens.
>
> On 80 and 160 meters, the toroids are normal temperature (around 100
> degrees) and everything works just fine since I?m not shorting turns on the
> toroids.
>
> Ideas?
> Thanks and 73
> Jim W7RY
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>
> --
> Dan Hearn
> N5AR
>
>
>
>
> --
> Dan Hearn
> N5AR
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 26 Mar 2014 15:43:06 +1030
> From: "Leigh Turner" <invertech@frontierisp.net.au>
> To: <amps@contesting.com>
> Subject: Re: [Amps] HV limit for rfc-3 choke?
> Message-ID: <F588A817B71D44439EB190F53980872F@Invertech>
> Content-Type: text/plain; charset="us-ascii"
>
>
> Excellent figuring Peter!
>
> An additional choke and bypass cap is almost essential to prevent
> deleterious 1.8 MHz RF blow-by into the HV power supply electrolytics.
>
> Mind you the HV "glitch" resistor also provides some attenuation of RF
> leakage when bypassed with a ceramic cap.
>
> Leigh
> VK5KLT
>
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of peter chadwick
> Sent: Wednesday, 26 March 2014 8:48 AM
> To: Carl; Rich Hallman - N7TR; amp reflector
> Subject: Re: [Amps] HV limit for rfc-3 choke?
>
> Figure it this way:
>
> Suppose you have 5kV DC and a plate swing of 8kV p-p or 2800 RMS. 225
> microhenries is 2545 ohms at 1.8 MHz so the RF current in the choke is 1.1
> amps, in addition to the DC. If Q = 100, R = 25 ohms and the power loss in
> the choke becomes 30 watts. That 1.1 amps needs a low impedance ground
> return, so that means something of the order of maybe 5nF to ground. Larger
> values can get too inductive on the higher bands... Even then, 5nF is 17
> ohms at 1.8 MHz, so there will be about 20 volts of RF at the base of the
> choke. That means you need another choke and capacitor to keep RF away from
> the HV electrolytics.
>
> I recently published an article in the journal of the Vintage and Military
> Amateur Radio Society on this: I can send a copy if anyone has any interest.
>
> 73
>
> Peter G3RZP
>
> ========================================
> Message Received: Mar 25 2014, 08:30 PM
> From: "Carl" <km1h@jeremy.mv.com>
> To: "Rich Hallman - N7TR" <rich@n7tr.com>, "amp reflector"
> <amps@contesting.com>
> Cc:
> Subject: Re: [Amps] HV limit for rfc-3 choke?
>
> I know people using them at 5KV from a 4-1000 to 3CX3000; they appear to
> hold up but I wouldnt want to experiment on RTTY with the 3X3 or bigger..
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Rich Hallman - N7TR" <rich@n7tr.com>
> To: "amp reflector" <amps@contesting.com>
> Sent: Tuesday, March 25, 2014 2:06 PM
> Subject: [Amps] HV limit for rfc-3 choke?
>
>
> > Will the rfc-3 choke work at 5kv? I know they say 4kv, but wanted to
> > know if others are using it at higher voltages?
> >
> > Thanks.... Rich N7TR
> > _______________________________________________
>
>
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Wed, 26 Mar 2014 11:53:35 +0000
> From: David Kirkby <david.kirkby@onetel.net>
> To: Amps@contesting.com
> Subject: [Amps] 50 V high current power supplies
> Message-ID:
> <CANX10hD97MAHT6Rv+6Ao3usbEu3jet9APMB3M_dGAt4W9rnkdA@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Someone in my local radio club is looking for a 50 V PSU for a
> home-brew linear he is thinking of making. I don't know exactly what
> power he is looking at, but I assume an put power of 1000 or more
> Watts would be needed, which is at least 20 A at 50 V. I believe there
> are some surplus HP or Compaq computer supplies around this voltage
> that some have used. Can anyone suggest any particular models that
> work well?
>
> Dave
>
>
> ------------------------------
>
> Message: 8
> Date: Wed, 26 Mar 2014 12:23:58 +0000
> From: Chris Wilson <chris@chriswilson.tv>
> To: Amps@contesting.com
> Subject: Re: [Amps] 50 V high current power supplies
> Message-ID: <166603411.20140326122358@chriswilson.tv>
> Content-Type: text/plain; charset=us-ascii
>
>
>
> Hello David,
>
> On Wednesday, March 26, 2014, you wrote:
>
> > Someone in my local radio club is looking for a 50 V PSU for a
> > home-brew linear he is thinking of making. I don't know exactly what
> > power he is looking at, but I assume an put power of 1000 or more
> > Watts would be needed, which is at least 20 A at 50 V. I believe there
> > are some surplus HP or Compaq computer supplies around this voltage
> > that some have used. Can anyone suggest any particular models that
> > work well?
>
> > Dave
>
> I use these, various sources have these from time to time, on Ebay:
>
> http://www.ebay.co.uk/itm/HP-253232-001-BL20p-3000W-PSU-POWER-SUPPLY-/300908478716?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=GQSUwXvo4QAuOLLWEcib%252BSw%252FgTk%253D&orig_cvip=true&rt=nc
>
>
>
> --
> Best regards,
> Chris mailto:chris@chriswilson.tv
>
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> ------------------------------
>
> End of Amps Digest, Vol 135, Issue 32
> *************************************
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