12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... Part 12
Here, some updates. This is the beginnings of the elaborate chain drive assy. 2 x more chains, yet to be installed, plus tensioner's....( for the vac tune + load caps).
Note on the big model 90 switch, there is a tall, rhombus shaped black end plate....at both ends of the switch assy....(oriented vertically).
In the normal configuration, the black end plate, at the FRONT of the switch is mounted on the INSIDE of the panel (along with the spring detent / nylon assy). In normal configuration, only the 1/4" steel shaft sticks out the front of the panel....through a panel bearing.
In this amplifier, the switch was taken apart, and the FRONT end plate was mounted on the OUTSIDE of the front (inner) panel....( along with the spring detent assy).
Done like this so the switch wafer assy doesn't stick as far back on the inside of the RF deck. There is severe space constraints on the inside of the RF deck.
Ferrite loaded plate choke finally fabricated...(and tweaked)....and tested on the VNA. It will be shipped out to Scott later this week. I had to make new, narrower copper straps ( 1/2" vs 3/4") so I could get an extra 8 turns onto the assy. The winding is now 5.5" long (vs 5.0") . Final choke config is now 405 uh. This dropped the 1st series resonance freq down to where I want it. (1st series resonance now at 17. 125 mhz...midway between top of 20m..and bottom of 15m..so choke won't work on 17m). The amp only works on 160-80-40-20-15m. NO 17/12/10m on this amp. It only has a 5 position bandswitch...with 4 x sequential rotors.... to make it into a shorting style bandswitch. And no, we can't re-use the 15M tap on 17m. Reason is, with the L coil inserted between the plate block cap assy, and the C1 vac tune cap, it's designed to lower the loaded tank on 15M. In software, if 15m tap re-used on 17m, the loaded tank Q skyrockets to an unacceptable value. Without the extra '"L" coil installed, the Q is too high on 15M..... BUT if re-used on 17M, would only increase the tank Q by another 17%. So L coil installed, low Q on 15m, and no 17m operation. Since no 17m operation, having the plate choke resonate near 17m band is a non issue. The model 90 switch is a 10 position, 36 deg switch. The max you can do with that switch is a 5 pole sequential rotor...which results in a 6 position bandswitch. Scott is re-using an old model 90 switch, and it only came with a 4 pole sequential rotor...so only 5 x bands.
Original loaded plate choke with it's 5" winding, was 305 uh, and resonated at 19.750 mhz....(and also 33 mhz). Interestingly enough, as an experiment, I removed 3/4" of turns so 12.5 turns removed...and winding was now only 4.25" long. Inductance dropped to 249 uh....and 1st series resonance shifted up to 23.3 mhz.... ( and 2nd series resonance shifted up to 39.990 mhz). Ok, winding completely removed....and new, narrower straps installed. This time, winding length increased to 5.5". Choke is now 405 uh. 1st series resonance is now 17.125 mhz.... ( and 2nd series resonance is now 29 mhz).
I believe this latest, and last config will work good. It will also minimize the residual RF current through the choke on 160m.
Stay tuned for more.
https://www.youtube.com/watch?v=exY4_UBmhsI
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Re: Kudos to Digi Key and Hammond Mfg.
What does it say on the SN on the dahl / Hammond xfmrs ??? ? Dahl / Hammond told me that it is NOT a SN, but the actual date code.?
I bought 2 of the dahl FWB rectifier assy's....just when dahl announced he was retiring....and had misc items on sale cheap.? ?Both of em have identical SN's.?
Then I found out yrs later ( just a few yrs ago, 2019), that the...'SN'? is actually the date code.? ( year / week built)? with 1st 2 digits being the year...and? digits 3+4 being the week...01-52).
?
I learn something new everyday.?
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Re: Identifying some rare tubes... 2nd
Even located in the adjacent room I can still hear an arc if were to occur. The 3x6 I¡¯m building now will have a spark gap on the c1 and c2 , grid overload , plate overload , cathode return fuse , grid current fuse , plate b+ fuse , series glitch plate b+, fuse in series with one side of the plate secondary , blower pressure interlock. Should be pretty bullet proof.
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On 2024-02-25 15:51, Steve wrote: On 2/25/2024 1:28 PM, Amp Guy Llc wrote:
But the real question is why would you want a noisy pa in the same
room with you. Because you wear headphones, and external noise doesn't bother you??
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Re: Identifying some rare tubes...
Headphones yeah I almost said that , but one of the main reasons a pa comes in for repair. Person has an open on the output , way outa tune or sone sort of other issue and they don¡¯t hear a component arcing away. In a standard multi pa usually ends up being the plate tune air variable cap and or the band switch.
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On 2024-02-25 15:51, Steve wrote: On 2/25/2024 1:28 PM, Amp Guy Llc wrote:
But the real question is why would you want a noisy pa in the same
room with you. Because you wear headphones, and external noise doesn't bother you??
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Re: Identifying some rare tubes...
Yes they will convert to a hi mu
Price last time I asked was roughly 2400 minus shipping to rebuild a 3cx15k . Not sure on the 3cx10k
Econco changed their warranty , now 1 year / 3000 filament hours whichever comes first.
Used to be 3000 hr filament and no limit on time to achieve.
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Re: Identifying some rare tubes...
Steve nobody puts a 3x3 or any other big tube into a desktop unit.? ?They all go into a standard 19"/ 24" rack.? Typ the blower hangs below the bottom of the chassis.? ?Putting a 100 lb box on a desk is nuts.?
My racks all sit in the shop next door.... 4 in total...all in a row.??
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Re: Identifying some rare tubes...
WB4VVI(SK) always told me when building/designing a transmitter or amp to use a tube that was pretty flat emission wise. No sense in screwing up a good tube on a miss-wired endeavor and/or a parasitic that may have unwittingly found itself into the construction!
Mod-U-Lator,
Mike(y)/W3SLK
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Amp Guy Llc Sent: Sunday, February 25, 2024 4:28 PM To: [email protected]Subject: Re: [ham-amplifiers] Identifying some rare tubes... Agreed, Don't start any amp project, unless you have at LEAST TWO known good tubes. And don't build any amp with more than one tube....pita. You will have a helluva time trying to play...'match up'. It's kinda hard to fit a 3x3 into a desktop cabinet. Good point jim. Also not good practice to build a pa around a tube that is near unobtanium. As for fitting a 3000 in a desk top cabinet, just make the plate supply separate and stick it under the desk. Presto Piece of cake. But the real question is why would you want a noisy pa in the same room with you. On 2024-02-25 13:40, Steve wrote: On 2/25/2024 10:52 AM, Jim VE7RF wrote:
Agreed, Don't start any amp project, unless you have at LEAST TWO
known good tubes. And don't build any amp with more than one
tube....pita. You will have a helluva time trying to play...'match
up'. It's kinda hard to fit a 3x3 into a desktop cabinet.
As a bonus, you can heat the home in winter, with...'free heat'.
... with a high 3-digit, maybe low 4-digit electric bill...
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Re: Identifying some rare tubes...
On 2/25/2024 1:28 PM, Amp Guy Llc wrote: But the real question is why would you want a noisy pa in the same
room with you. Because you wear headphones, and external noise doesn't bother you??
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Re: Identifying some rare tubes...
"rebuilt? by econco, and they will replace the grid with a high mu grid"?I suppose that is only possible with the 3X15 because a hi mu grid component is available? Does anyone know the cost of a 3CX10/15 rebuild $?? ballpark, I've never done it.
A couple of those tubes with flex leads are Thales ITL9-1's (low mu oscillator tubes) I guess there is unlikely to be a hi mu grid for them :-(
https://soudeuse-haute-frequence.com/nos_produits/triode/ITL9-1.pdf
Tim
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Re: Identifying some rare tubes...
Agreed, Don't start any amp project, unless you have at LEAST TWO
known good tubes. And don't build any amp with more than one
tube....pita. You will have a helluva time trying to play...'match up'.
It's kinda hard to fit a 3x3 into a desktop cabinet.
Good point jim.
Also not good practice to build a pa around a tube that is near unobtanium.
As for fitting a 3000 in a desk top cabinet, just make the plate supply separate and stick it under the desk. Presto Piece of cake.
But the real question is why would you want a noisy pa in the same room with you.
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On 2024-02-25 13:40, Steve wrote: On 2/25/2024 10:52 AM, Jim VE7RF wrote:
Agreed,? Don't start any amp project, unless you have at LEAST TWO
known good tubes.? ? And don't build any amp with more than one
tube....pita.? ?You will have a helluva time trying to play...'match up'. It's kinda hard to fit a 3x3 into a desktop cabinet.
As a bonus, you can heat the home in winter, with...'free heat'.
... with a high 3-digit, maybe low 4-digit electric bill...
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Re: Identifying some rare tubes...
On 2/25/2024 10:52 AM, Jim VE7RF wrote: Agreed,? Don't start any amp project, unless you have at LEAST TWO
known good tubes.? ? And don't build any amp with more than one
tube....pita.? ?You will have a helluva time trying to play...'match up'. It's kinda hard to fit a 3x3 into a desktop cabinet.
As a bonus, you can heat the home in winter, with...'free heat'.
... with a high 3-digit, maybe low 4-digit electric bill...
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Re: Identifying some rare tubes...
On Sat, Feb 24, 2024 at 11:40 PM, Steve wrote:
>Regardless, with just one unknown-condition example of either, you'd be foolhardy to design anything around one...
>Steve, K0XP
Agreed,? Don't start any amp project, unless you have at LEAST TWO known good tubes.? ? And don't build any amp with more than one tube....pita.? ?You will have a helluva time trying to play...'match up'.??
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.?
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Re: Identifying some rare tubes...
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:
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
Sent:
Saturday, February 24, 2024 4:19 PM
To:
[email protected]
Subject: Re:
[ham-amplifiers] Identifying some rare tubes...
?
Indeed, but sadly the only other
pictures I have:
  
Looks like this? (reading backwards through the glass) is
a 6T51?
Designed as an industrial heater oscillator triode.? Not
sure it would be much use for anyone here?
--
See my QRZ.com page at
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Re: Identifying some rare tubes...
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 ? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern
Sent: Saturday, February 24, 2024 4:19 PM
To: [email protected]
Subject: Re: [ham-amplifiers] Identifying some rare tubes... ? Indeed, but sadly the only other pictures I have:
  
Looks like this? (reading backwards through the glass) is a 6T51?
Designed as an industrial heater oscillator triode.? Not sure it would be much use for anyone here?
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Re: Identifying some rare tubes...
Indeed, but sadly the only other pictures I have:    Looks like this? (reading backwards through the glass) is a 6T51? Designed as an industrial heater oscillator triode.? Not sure it would be much use for anyone here?
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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 ±õ¶Ù¡¯¾±²Ô²µ them a might easier! ? Just sayin¡¯! ? Joe ¨C W7RKN ? From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern
Subject: [ham-amplifiers] Identifying some rare tubes... ? I've been offered this job lot from a SK sale...
I recognise 3CX15k, 4CX5k, Gu81m, ITL9-1, BR1106, Vac-Vars (10-200, 25kV) any idea's for the rest?
There are some kanji characters on the big glass bulbs, so Japanese maybe
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Re: Identifying some rare tubes...
Just a thought¡perhaps putting the items on a white, non-patterned background, might make ±õ¶Ù¡¯¾±²Ô²µ them a might easier! ? Just sayin¡¯! ? Joe ¨C W7RKN ? From: [email protected] [mailto:[email protected]] On Behalf Of Tim Fern
Subject: [ham-amplifiers] Identifying some rare tubes... ? I've been offered this job lot from a SK sale...
I recognise 3CX15k, 4CX5k, Gu81m, ITL9-1, BR1106, Vac-Vars (10-200, 25kV) any idea's for the rest?
There are some kanji characters on the big glass bulbs, so Japanese maybe
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Identifying some rare tubes...
I've been offered this job lot from a SK sale... I recognise 3CX15k, 4CX5k, Gu81m, ITL9-1, BR1106, Vac-Vars (10-200, 25kV) any idea's for the rest? There are some kanji characters on the big glass bulbs, so Japanese maybe ? 
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Re: Kudos to Digi Key and Hammond Mfg.
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.? :)
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Re: Ameritron Plate Chokes
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.?
?
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