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Re: Identifying some rare tubes...
On Sat, Feb 24, 2024 at 11:40 PM, Steve wrote:
That 3x15 triode with the flex leads is the H3 version.? ?Those are low mu...and useless? for cathode driven / GG amplifier service.? ?However, it can be rebuilt? by econco, and they will replace the grid with a high mu grid. It's done all the time.? Then it becomes the ultimate tube, since no socket required.? ?Just bolt the grid flange to the chassis.? Apply 1.5 kw of drive....and blast away with 30 kw pep out.? As a bonus, you can heat the home in winter, with...'free heat'. ? We have the fil choke for those 160 amp and lower down to a fine art.? It's just a simple matter of sliding a mess of fair-rite type 43 oval beads over a pair of 1-0 power cables....done..... in abt 20 secs flat.? |
Re: Identifying some rare tubes...
开云体育Regardless, with just one unknown-condition example of either, you'd be foolhardy to design anything around one... Steve, K0XP
On 2/24/2024 2:29 PM, Mike Sawyer via
groups.io wrote:
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See my QRZ.com page at |
Re: Identifying some rare tubes...
开云体育Strange. On the link you sent on one photo it shows the 6T51 as a glass tube but on another photo it shows it as an external anode. Even on evilbay they show a 6T51 as an external anode as a FU-605. ? Mod-U-Lator, Mike(y)/W3SLK ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern ? Indeed, but sadly the only other pictures I have: |
Re: Identifying some rare tubes...
I agree. The pattern on the background makes it a little confusing.
On Saturday, February 24, 2024 at 11:52:41 AM EST, Joe - W7RKN <w7rkn.7@...> wrote:
Just a thought…perhaps putting the items on a white, non-patterned background, might make 滨顿’颈苍驳 them a might easier! ? Just sayin’! ? Joe – W7RKN ? From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern ? I've been offered this job lot from a SK sale... _._,_ |
Re: Identifying some rare tubes...
开云体育Just a thought…perhaps putting the items on a white, non-patterned background, might make 滨顿’颈苍驳 them a might easier! ? Just sayin’! ? Joe – W7RKN ? From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern ? I've been offered this job lot from a SK sale... _._,_ |
Re: Kudos to Digi Key and Hammond Mfg.
NI5L
Like Steve said, Digi Key is the only way to order them. The original in my amp was a Magnelab. They are poorly built and according to Glenn, all of the Magnelab transformers have failed. Alpha was replacing them as late as 2009 under warranty, if I recall what he told me correctly.?
Anyway, my 99 is good to go and I am loving busting pileups again.? :) |
Re: Ameritron Plate Chokes
开云体育Atr 50Hz 1.2A will be permitted when winding a transformer with that wire. At free air 14A will be maximum. ? 73 Peter, DJ7WW ? ? ? -----Original-Nachricht----- Betreff: Re: [ham-amplifiers] Ameritron Plate Chokes Datum: 2024-02-22T17:36:36+0100 Von: "Jim VE7RF" <jim.thom@...> ? ? I measured the OD of the magnet wire, and it's .028".? It's 22 ga all right.? (.028" OD on the enamel).? Started at 5 amps CCS for 20 mins, then increased the current.? Stone cold at 7 amps. Started to warm up at 9 amps, and I could definitely feel the heat with supply maxed out at 11 amps CCS.? That was an eye opener.? That's open air. Wind a plate choke with it, and the max CCS DC current rating drops like a rock.? |
Re: Ameritron Plate Chokes
开云体育Oopsie... I didn't notice earlier that you mentioned the 8K's choke is wound on teflon... Steve, K0XP On 2/22/2024 8:52 AM, Steve wrote:
--
See my QRZ.com page at |
Re: Ameritron Plate Chokes
开云体育Yup; PTFE's a pretty good thermal insulator at low temperatures (i.e.: below its melting or burning point), especially compared to ceramic. Moreover, the ceramic can take a couple thousand degrees before it'll suddenly fail (likely by shattering); not so with that PTFE rod. Also, consider just how long you're letting that current heat up
the wire and ceramic rod; it'll take more current when cold
compared to after it's been warmed up. A glazed ceramic rod would probly suck up more heat since its surface is smooth and thus makes good thermal contact with the wire, compared to the unglazed ceramic rod. I would expect that if you ran the same thermal runaway test using an equivalent glazed ceramic rod, it would probly allow higher current (and thus higher temperature), but then once the rubicon is crossed, it might also show a faster thermal runaway characteristic. If the 8K's choke is wound on a glazed ceramic rod, that's likely why it takes off so quickly. Or perhaps its wire isn't making as good contact to the coil form. It's all Thermodynamics? 8-) Steve, K0XP On 2/22/2024 8:36 AM, Jim VE7RF wrote:
--
See my QRZ.com page at |
Re: PA tube testing, Interesting findings.
开云体育Kinda hard to fit a 3CX3000-anything into a 7-inch-high desktop cabinet, even without anything connected to the top or bottom? 8-)
On 2/22/2024 8:05 AM, Jim VE7RF wrote:
--
See my QRZ.com page at |
Re: Ameritron Plate Chokes
While on a roll, I tested both my Ameritron plate chokes.... by hooking em up to my small 0-36 vdc @ 3 amp CCS lab supply.? What baffles me is the 180 uh large choke, used in the 8K ultra also runs at room temp, with 1.5 amps CCS.? Any higher than that, and it heats up incredibly fast.? It will burn ur fingers with 1.8 amps.? Scott's theory is the 1" diameter, solid? Un-glazed ceramic used on the Ameritron choke may well be absorbing any heat.? ?Whereas the 1" solid Teflon rod used on the Henry choke is the ultimate heat insulator.? The magnet wire used on the 8K appears to be bigger than what's used on the Ameritron, like by at least 2 gauges.?? ? Years ago, I ran a test, by stuffing 5 amps CCS, through a 3' length of 22 ga magnet wire, laying on the carpet, in a big circle....with the ends directly into my 0-60 vdc @ 5 amp? CCS lab supply.? Stone cold after 1 hr.? So no clue at the time exactly how much 22 ga magnet wire will handle in free air.? While using the same 5 amp lab supply to test the recently acquired 4H, 127 lb Dahl choke, something was amiss, and for whatever reason,? I quickly disconnected? one of the 18 ga test leads to the choke (with I think 5 amps flowing through it), and the back EMF took out the 5 amp lab supply, white smoke billowing out of it.? ?Those lab supplies have every protection there is...except for back emf.? The fix is? to install a RVS connected diode across the output of the lab supply.? Dunno why they didn't install one internally.? Ok, bought another 0-60 vdc supply, but this time a 10 amp CCS unit. (they also made a 15 amp unit).? Dragged it out the other day....and ran the same test, through another 4' piece of 22 ga magnet wire, also in a loop, with 3/4 of it in mid air, and hardly any of it touching the carpet.? I measured the OD of the magnet wire, and it's .028".? It's 22 ga all right.? (.028" OD on the enamel).? Started at 5 amps CCS for 20 mins, then increased the current.? Stone cold at 7 amps. Started to warm up at 9 amps, and I could definitely feel the heat with supply maxed out at 11 amps CCS.? That was an eye opener.? That's open air. Wind a plate choke with it, and the max CCS DC current rating drops like a rock.? |
Re: Inductive EHT filtering
开云体育Don't nobody be intending to call and talk to Tim on the phone over the weekend; he'll have his ears plugged with wads of paper in anticipation of those bangs? 8-D
On 2/22/2024 8:22 AM, Tim Fern wrote:
"?They will work for B+ applications, but have to be-derated for voltage." .... that's the question, right there. --
See my QRZ.com page at |
Re: Inductive EHT filtering
"?They will work for B+ applications, but have to be-derated for voltage." .... that's the question, right there.
If it's rated 8kV, will it cope with 6,500V?? Because if it doesn't , 800J is going to make a big bang :-(? ? ? We will find out over the weekend. According to PSUD2, simply using the 38uF will fix the ripple problem without using the choke too. |
Re: PA tube testing, Interesting findings.
开云体育If you are using more than one tube, you are using the wrong tube!73, Mike Mysliwiec KF8OD
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Re: PA tube testing, Interesting findings.
How do you match them up...even if they are good ?? ? ?2 tubes are bad enough....and 3 of em is a pita.? After that, it was just a single tube for any hb amp.? Need more PO, use the next bigger tube that is available.? ?IE: 3x3, 3x6, 3x10, 3x20.? ?Or 4x5, 4x10, 4x15.? ?Pick just one of either triode or tetrode.? |
Re: Kudos to Digi Key and Hammond Mfg.
On 2/21/2024 7:42 PM, Jim VE7RF wrote:
I tried ordering my replacment 2K4A XFMR from Dahl/Hammond, and they told me I had to order it through DigiKey because DK was now their distributor; so I did. Initially, there was some confusion; the DK person on email (I cannot hear on a phone, so have to use either text or email) didn't think there was such a model as what I wanted. I asked her to check with Dahl/Hammond, who had told me to order from DK; I gave her the name of the person I'd corresponded with at Dahl/Hammond. She did, then I got an order-confirming e-mail after a few days asking for my DK account schtuff. Once I gave that, it was another few days until I got an ack from DK they had received that info. THEN I waited TWO WEEKS with no ack they had accepted my order; so I emailed again, they said they'd check... and finally, a couple days later, I received an e-mail acknowledging my complete order... and listing a delivery time some FOUR-PLUS months down the road. I initially emailed Dahl/Hammond in late January, DK finally sent this email around the middle of March. The delivery was scheduled, by FEDEX Fright, for the middle of July, IIRC. As it happened, this all occurred just prior to, and then during, the first few months of CV-19. I was finally alerted by FEDEX around the end of June that my XFMR would be available for pickup locally in a couple weeks, then in a week got another e-mail it would be on time when they said. After FEDEX emailed me that last time, they emailed me again several times, trying to claim my XFMR had been sitting there waiting for me for a week, and they would return it as "Unclaimed"... as it happened, on the SAME date they had originally said it would be available for pickup. I had to have my brother get on the phone with them and he finally got through to them I was WAITING for the delivery date. ... And then finally, I drove there (turned out to be just a couple miles away from where I lived at the time), the forklift brought it out, and I had to cut it loose from the pallet and get it out of the wooden box, both of which may have weighed almost as much as the XFMR. The parking lot had a lot of pallets that customers had cut their goods loose from. It all was an adventure I don't want to repeat. Steve, K0XP |
Re: Kudos to Digi Key and Hammond Mfg.
Why did u have to go through digikey..and not directly with hammond / dahl ?? ?? NO hv sag at all, that's superb.? IMO, whatever the B+ is? with amp keyed, and sucking normal idle current is the real no load B+.? ?It has to idle 1st, before you ac apply drive.? ?I really could care less what it is in RX.? ?But that has it's limitations.? Like if EBS is used, etc.? Dahl never went cheap with the insulation..and neither did Hammond.? I still have hammond plate xfmrs made in the late 50's that still function, even with floating CT's....and also stuffing 247 vac into the 210 vac pri.? |
Re: Inductive EHT filtering
Some oil caps were meant for energy discharge, ( like laser discharge)? and have higher internal ESR.? ?They will work for B+ applications, but have to be-derated for voltage.? ?Typ oil caps used for B+ applications, used in TX / PA applications have zero esr.? ?I can measure ESR on my B+K 875B, since it measures AC resistance, instead of DC resistance.... but only at 1 khz.? ?It uses a 1 khz square wave, so it can't be used on the pri of a plate xfmr, to measure resistance. On stuff like 450 vdc lytics, the measured esr at 1 khz, will be a lot lower vs the normal 100/120 hz.? Better LCR meter's will measure at several freqs.? I have to factor in a? correction factor.? ?EG: my big 10,000 uf @ 450 vdc lytics (3" diam x 8.625" tall, 3.3 lbs) measure just .005 ohms at 1 khz..... when in actuality, they are really .0159 ohms? @ 120 hz.?? ? Are you still going to use the choke....or just add the 38 uf filter cap onto the output of the existing B+ supply ?? ?Either way, I would insulate the oil cap from the chassis.? ? So far, when comparing PSUD-2? ?vs? reality.... it's dead on for the most part, provided every last thing is entered correctly.? I talked with Duncan, who designed it.? I have been using it for yrs now.? The previous versions had a lot of short comings, so I developed some work arounds.? Just before CV-19,? I mentioned a bunch of issues with the current PSUD-2? ?with Duncan.? ?A lot of it was software limitations.? Like when you add an LC section, with just a series choke, and then use the bypass cap at the cold end of the plate choke for the ...'C'.? ? It results in a ton of...'noise'.? The giveaway is when it? runs at a crawl.? Duncan has my mile long list for the new? PSUD-3.? But CV-19 came about, and it all went to hell.? PSUD-2? won't handle? negative power supplies, only positive supplies.? ?It won't handle glitch resistor's,? nor? 3 phase power,? nor resonant chokes.? It won't spit out results for ripple, other than 100/120 hz.? ? ?It's pretty good for what it does though...and is easy to use.? |