The choke is a lot more robust than you would think.? I've had a
couple of them pop over the years but tracked that down to a
resonance (AKA idiot builder error) each time.? Fix the resonance
(reposition), patch the choke and back in biz.? The size of the
choke wire from a "can it carry the plate current" standpoint is
definitely fine for typical use - unless you are in the fire
breathing realm.?
If you don't believe it and want to feel better about it, hang a
few sizes of mid 30's gauge wire on a constant current supply and
see how just high you have to bump that current to get it to open
up.? You may be surprised.
73/jeff/ac0c
alpha-charlie-zero-charlie
On 12/2/19 10:13 AM, cturnertuning
wrote:
toggle quoted message
Show quoted text
This confirms your choke is the "fuse" in your amplifier. If
you are ok with that Dave, then great. I have one in an AM plate
modulated amplifier with a pair of 4-400s modulated by a pair of
304TLs. The choke has survived. I have had failures but was
running them past the ratings. Did your choke unravel?? That
seems to be the type of failure with these. One good bang and
they un wind on the form.
C
On 11/30/2019 7:15 PM, DAVE WHITE via
Groups.Io wrote:
“Ratings are
guidelines” - yeah that what this guy at Essen Motor Show
said this weekend (picture attached)?
In my 3CX3000A7 amp I used a very similar choke (in fact it
looks the same) bought from RF Parts. ?I think it too is rated
at 4kv 1.5A. ?
I’ve had one failure in 18 years with the amp and that was
the choke. ?I use a glitch resistor and an HRC fuse inthe ?HT
line which worked fine and protected the amp when the
insulator at the end of my top band 3/8 inverted L exploded
one night, thus leaving the choke ok. ?But one day about 10
years ago the choke just went BANG. ?I never worked out why.
?I replaced it with another identical one and (touch wood)
it’s been ok since.?
I know that B&W used to make a much higher rated choke
years ago but they seem to be unobtainium now. ?I run 5.5kv
resting voltage on the anode so always knew that the plate
choke was the weakest point.?
That looks like a nice amp in the pictures.
I used two rollercoasters and two vacuum capacitors as a
Pi-L 10-160m, by the way. ?
I bought a mix of A7 and F7 tubes from the Dayton flea
market so bought an A7 socket and removed the filament rings
and flying leads from the F7s with a little heat. ?They’re
just held on there with soft solder. ?The idea was that a tube
change is much easier.?
73 Dave?
On Sunday,
December 1, 2019, 2:30 am, Carl <km1h@...>
wrote:
Yep, while the designer ran a full bore 2 hole
AL-1500 with no problems the company went to a lower
rating to minimize warranty issues.
?
Note I also stressed the layout as many Hammy
Hambone amp builders havent a clue about coupling and
"parasitic" resonances..Not AG6K parasitics!?
?
Carl
----- Original Message
-----
Sent: Friday,
November 29, 2019 12:27 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp
peak. It is the weak link for sure. But if it
works it works. Better have a glitch. One arc
and its done. In this example its a fuse.:)
Sent from my
T-Mobile 4G LTE device
The Ameritron choke will easily handle
2A?from that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
-----
Original Message -----
Sent:
Wednesday, November 27, 2019 10:40 AM
Subject:
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is
screaming for its life :) Very cool
amplifier!
On
11/26/2019 6:53 PM, Mike via
wrote:
My latest amplifier.
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
>From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
This confirms your choke is the "fuse" in your amplifier. If you
are ok with that Dave, then great. I have one in an AM plate
modulated amplifier with a pair of 4-400s modulated by a pair of
304TLs. The choke has survived. I have had failures but was
running them past the ratings. Did your choke unravel?? That seems
to be the type of failure with these. One good bang and they un
wind on the form.
C
On 11/30/2019 7:15 PM, DAVE WHITE via
Groups.Io wrote:
“Ratings are
guidelines” - yeah that what this guy at Essen Motor Show said
this weekend (picture attached)?
In my 3CX3000A7 amp I used a very similar choke (in fact it looks
the same) bought from RF Parts. ?I think it too is rated at 4kv
1.5A. ?
I’ve had one failure in 18 years with the amp and that was
the choke. ?I use a glitch resistor and an HRC fuse inthe ?HT
line which worked fine and protected the amp when the insulator
at the end of my top band 3/8 inverted L exploded one night,
thus leaving the choke ok. ?But one day about 10 years ago the
choke just went BANG. ?I never worked out why. ?I replaced it
with another identical one and (touch wood) it’s been ok since.?
I know that B&W used to make a much higher rated choke
years ago but they seem to be unobtainium now. ?I run 5.5kv
resting voltage on the anode so always knew that the plate choke
was the weakest point.?
That looks like a nice amp in the pictures.
I used two rollercoasters and two vacuum capacitors as a Pi-L
10-160m, by the way. ?
I bought a mix of A7 and F7 tubes from the Dayton flea market
so bought an A7 socket and removed the filament rings and flying
leads from the F7s with a little heat. ?They’re just held on
there with soft solder. ?The idea was that a tube change is much
easier.?
73 Dave?
On Sunday, December
1, 2019, 2:30 am, Carl <km1h@...> wrote:
Yep, while the designer ran a full bore 2 hole
AL-1500 with no problems the company went to a lower
rating to minimize warranty issues.
?
Note I also stressed the layout as many Hammy Hambone
amp builders havent a clue about coupling and
"parasitic" resonances..Not AG6K parasitics!?
?
Carl
----- Original Message
-----
Sent: Friday,
November 29, 2019 12:27 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp
peak. It is the weak link for sure. But if it
works it works. Better have a glitch. One arc and
its done. In this example its a fuse.:)
Sent from my
T-Mobile 4G LTE device
The Ameritron choke will easily handle
2A?from that tube on CW and SSB.
It is also well placed for minimum coupling.
?
Carl
-----
Original Message -----
Sent:
Wednesday, November 27, 2019 10:40 AM
Subject:
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is
screaming for its life :) Very cool amplifier!
On
11/26/2019 6:53 PM, Mike via wrote:
My latest amplifier.
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
>From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
“Ratings are guidelines” - yeah that what this guy at Essen Motor Show said this weekend (picture attached)?
In my 3CX3000A7 amp I used a very similar choke (in fact it looks the same) bought from RF Parts. ?I think it too is rated at 4kv 1.5A. ?
I’ve had one failure in 18 years with the amp and that was the choke. ?I use a glitch resistor and an HRC fuse inthe ?HT line which worked fine and protected the amp when the insulator at the end of my top band 3/8 inverted L exploded one night, thus leaving the choke ok. ?But one day about 10 years ago the choke just went BANG. ?I never worked out why. ?I replaced it with another identical one and (touch wood) it’s been ok since.?
I know that B&W used to make a much higher rated choke years ago but they seem to be unobtainium now. ?I run 5.5kv resting voltage on the anode so always knew that the plate choke was the weakest point.?
That looks like a nice amp in the pictures.
I used two rollercoasters and two vacuum capacitors as a Pi-L 10-160m, by the way. ?
I bought a mix of A7 and F7 tubes from the Dayton flea market so bought an A7 socket and removed the filament rings and flying leads from the F7s with a little heat. ?They’re just held on there with soft solder. ?The idea was that a tube change is much easier.? 73 Dave?
On Sunday, December 1, 2019, 2:30 am, Carl <km1h@...> wrote:
Yep, while the designer ran a full bore 2 hole
AL-1500 with no problems the company went to a lower rating to minimize warranty
issues.
?
Note I also stressed the layout as many Hammy
Hambone amp builders havent a clue about coupling and "parasitic"
resonances..Not AG6K parasitics!?
?
Carl
----- Original Message -----
Sent: Friday, November 29, 2019 12:27
AM
Subject: Re: [ham-amplifiers] 3CX3000F7
10-80m
Ratings are guidelines.
73, Alek
VK6APK
On
29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It is the
weak link for sure. But if it works it works. Better have a glitch. One arc
and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G LTE
device
The Ameritron choke will easily handle
2A?from that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
-----
Original Message -----
Sent:
Wednesday, November 27, 2019 10:40 AM
Subject:
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is screaming for its life :) Very
cool amplifier!
On 11/26/2019 6:53 PM, Mike via
wrote:
My latest amplifier.   --
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
?
Yep, while the designer ran a full bore 2 hole
AL-1500 with no problems the company went to a lower rating to minimize warranty
issues.
?
Note I also stressed the layout as many Hammy
Hambone amp builders havent a clue about coupling and "parasitic"
resonances..Not AG6K parasitics!?
?
Carl
----- Original Message -----
Sent: Friday, November 29, 2019 12:27
AM
Subject: Re: [ham-amplifiers] 3CX3000F7
10-80m
Ratings are guidelines.
73, Alek
VK6APK
On
29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It is the
weak link for sure. But if it works it works. Better have a glitch. One arc
and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G LTE
device
The Ameritron choke will easily handle
2A?from that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
-----
Original Message -----
Sent:
Wednesday, November 27, 2019 10:40 AM
Subject:
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is screaming for its life :) Very
cool amplifier!
On 11/26/2019 6:53 PM, Mike via
wrote:
My latest amplifier.   --
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
The only issue that may occur is sourcing the valves for the Alpha. When last checked they were made of unobtanium rgds
On Wed, Nov 27, 2019 at 9:24, Jim Strohm <jim.strohm@...> wrote: Depends on what "cheaper" means.? Too many hams will cheap out at every possible opportunity, frequently to their detriment later.
You can see today that the Alpha has a much greater retained value.? It probably has better engineering.? Another consideration is the availability of replacement finals down the line.?
As a perennial contributor here used to say, "horses for courses."? Your considerations for amp purchase won't be the same as those of other hams.? If it's ONLY "cheap" -- then I have a D&A Phantom amp I'll sell for real cheap.
73 Jim N6OTQ
On Wed, Nov 27, 2019 at 4:03 AM David Perry < bumbledp@...> wrote: Hi guys.? Ive just been subscribed to this group.? Greetings one and all.
Q: ?Alpha 76 or FL2100B amp...which to buy.? I have seen one of each at reasonable prices.? I see the 2100 has no top band (pity) and the Alpha looks cosmetically a bit better but the 2100 is cheaper...by far.
Any advice?
73
--
David G4YVM
|
The only issue with the Alpha 76, that may occur is the scarcity of valves rgds
On Wed, Nov 27, 2019 at 9:24, Jim Strohm <jim.strohm@...> wrote: Depends on what "cheaper" means.? Too many hams will cheap out at every possible opportunity, frequently to their detriment later.
You can see today that the Alpha has a much greater retained value.? It probably has better engineering.? Another consideration is the availability of replacement finals down the line.?
As a perennial contributor here used to say, "horses for courses."? Your considerations for amp purchase won't be the same as those of other hams.? If it's ONLY "cheap" -- then I have a D&A Phantom amp I'll sell for real cheap.
73 Jim N6OTQ
On Wed, Nov 27, 2019 at 4:03 AM David Perry < bumbledp@...> wrote: Hi guys.? Ive just been subscribed to this group.? Greetings one and all.
Q: ?Alpha 76 or FL2100B amp...which to buy.? I have seen one of each at reasonable prices.? I see the 2100 has no top band (pity) and the Alpha looks cosmetically a bit better but the 2100 is cheaper...by far.
Any advice?
73
--
David G4YVM
|
That choke is meant for small desk top amps with small tubes. Any commercial 3000 amp would have a much larger choke or two chokes. I have three of those failed here from different amps and olate modulated amps. If you get a flash over or surpass the current rating it will expand and unwind. I tried to run a pair of 3-1000z tubes at 5000 to 6000 volts and every time they failed. Finally went to a much larger choke. You might get away with it for now but not at high power and not if you you have an event at tube side or tank.?
Sent from my T-Mobile 4G LTE device
------ Original message------ From: Alek Petkovic Date: Thu, Nov 28, 2019 10:27 PM Cc: cturnertuning;Carl; Subject:Re: [ham-amplifiers] 3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It
is the weak link for sure. But if it works it works. Better have a
glitch. One arc and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G
LTE device
The Ameritron choke will easily
handle 2A?from that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
-----
Original Message -----
To:
[email protected]
Sent:
Wednesday, November 27, 2019 10:40 AM
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is screaming for its life :)
Very cool amplifier!
On 11/26/2019 6:53 PM, Mike via wrote:
My latest amplifier.  
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It
is the weak link for sure. But if it works it works. Better have a
glitch. One arc and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G
LTE device
The Ameritron choke will easily
handle 2A?from that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
-----
Original Message -----
Sent:
Wednesday, November 27, 2019 10:40 AM
Subject:
Re: [ham-amplifiers] 3CX3000F7 10-80m
That little Ameritron plate choke is screaming for its life :)
Very cool amplifier!
On 11/26/2019 6:53 PM, Mike via wrote:
My latest amplifier.  
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
--
From sunny Binningup
Family Businesses:
SP Electrical.
The Velvet Fox.
Smart Design Electrical.
Perth Interiors.
|
Not really. Its rated at 4kv max and 1.5 amp peak. It is the weak link for sure. But if it works it works. Better have a glitch. One arc and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G LTE device
------ Original message------ From: Carl Date: Thu, Nov 28, 2019 6:25 PM Cc: Subject:Re: [ham-amplifiers] 3CX3000F7 10-80m
The Ameritron choke will easily handle 2A?from
that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
----- Original Message -----
Sent: Wednesday, November 27, 2019 10:40
AM
Subject: Re: [ham-amplifiers] 3CX3000F7
10-80m
That little Ameritron plate choke is screaming for its life :) Very cool
amplifier!
On 11/26/2019 6:53 PM, Mike via
wrote:
My
latest amplifier.   --
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
?
Nice amp. I see very few using the F version which
is often a real bargain even NOS.
?
Carl
----- Original Message -----
Sent: Tuesday, November 26, 2019 8:53
PM
Subject: [ham-amplifiers] 3CX3000F7
10-80m
My latest amplifier.  
|
?
The Ameritron choke will easily handle 2A?from
that tube on CW and SSB.
It is also well placed for minimum
coupling.
?
Carl
----- Original Message -----
Sent: Wednesday, November 27, 2019 10:40
AM
Subject: Re: [ham-amplifiers] 3CX3000F7
10-80m
That little Ameritron plate choke is screaming for its life :) Very cool
amplifier!
On 11/26/2019 6:53 PM, Mike via Groups.Io
wrote:
My
latest amplifier.   --
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
David
In terms of reliabilty there is nothing to choose
Alpha didnt advertise their "brick on key" amps for a joke - they really can do it!
Particulary if the 76 has 3 valves go for it!
Spares are getting harder to find though
There is an Alpha 76 on the G3CWI selling site as well
73 Fred
G4BWP
toggle quoted message
Show quoted text
On Wed, Nov 27, 2019 at 10:03 AM, David Perry wrote:
Hi guys. ?Ive just been subscribed to this group. ?Greetings one and all.
Q: ?Alpha 76 or FL2100B amp...which to buy. ?I have seen one of each at
reasonable prices. ?I see the 2100 has no top band (pity) and the Alpha looks
cosmetically a bit better but the 2100 is cheaper...by far.
Any advice?
73
--
David G4YVM
|
That little Ameritron plate choke is screaming for its life :)
Very cool amplifier!
On 11/26/2019 6:53 PM, Mike via
Groups.Io wrote:
My latest amplifier.  
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
Depends on what "cheaper" means.? Too many hams will cheap out at every possible opportunity, frequently to their detriment later.
You can see today that the Alpha has a much greater retained value.? It probably has better engineering.? Another consideration is the availability of replacement finals down the line.?
As a perennial contributor here used to say, "horses for courses."? Your considerations for amp purchase won't be the same as those of other hams.? If it's ONLY "cheap" -- then I have a D&A Phantom amp I'll sell for real cheap.
73 Jim N6OTQ
On Wed, Nov 27, 2019 at 4:03 AM David Perry < bumbledp@...> wrote: Hi guys.? Ive just been subscribed to this group.? Greetings one and all.
Q: ?Alpha 76 or FL2100B amp...which to buy.? I have seen one of each at reasonable prices.? I see the 2100 has no top band (pity) and the Alpha looks cosmetically a bit better but the 2100 is cheaper...by far.
Any advice?
73
--
David G4YVM
|
Hi guys. ?Ive just been subscribed to this group. ?Greetings one and all.
Q: ?Alpha 76 or FL2100B amp...which to buy. ?I have seen one of each at reasonable prices. ?I see the 2100 has no top band (pity) and the Alpha looks cosmetically a bit better but the 2100 is cheaper...by far.
Any advice?
73
--
David G4YVM
|
Fantastic
eye candy here Mike on a nicely executed 3CX3000 amp; Bravo!
?
Thanks
for sharing the pics…
?
Leigh
VK5KLT
?
My latest amplifier:
?
. ?  ?? ?
|
|
|
Should have? added...
I use? his? coil? program? for? loading coils
for 40m? yagis...? and? also tank? coils? for? hb amps.? Since? it? spits out
RF? resistance for a given freq,? and? knowing the exact RF? current? flowing?
through the? coil, pretty? easy? to? then? calculate the? diss in watts...in?
the? coil.?? For? tapped? tubing? coils,? like a 20m? tubing coil,? tapped? for
17,15, 12,10m....and? say on? 15M, any? heat is? localized to? the? portion? of?
the coil? being used.? I? would have? thought the? un-used portion of
the?
coil would act as a heat? sink....? it? does not !?? Unused turns? remain? at
ambient? room? temp.....? while used? turns can? be? extremely? hot? to? the?
touch.???
?
Jim??
VE7RF
|
K6STI? has? an? upgraded? FREE? coil? software version? on? his? website?
below.
Coil? 3.72 is? at? the? extreme? bottom? of left? column.
Note,? by? left clicking? on the? ....AWG,? u? can? toggle? between?
AWG...and? decimal points of an inch.
It? will? handle? awg? up? to a max?? of? 0? gauge wire?? =? .3249 inch.??
Min? AWG? is? 52 AWG =? .008 inch.
In? decimal points of an? inch? mode,? it? will? handle? tubing? up to a
max of .5 inch? OD.
?
By? left? clicking? on? the ..ditto marks? below? AWG....? u? can? toggle?
coil diam,? length, lead length,? form? thickness,?? between? inches? and? mm.?
I use? his? coil? program? for? loading coils for 40m? yagis...? and? also tank? coils? for? hb amps.? Since? it? spits out RF? resistance for a given freq,? and? knowing the exact RF? current? flowing? through the? coil, pretty? easy? to? then? calculate the? diss in watts...in? the? coil.?
?
Jim?? VE7RF
?
?
|
Re: Migration to Groups.Io
Once the group is migrated, all members here will automatically be members in the new group.? I would suggest that all uploads and photos be stopped until after the migration, as there would be a good chance they would be missed in the move. ? Joe – W7RKN From: ham_amplifiers@... [mailto:ham_amplifiers@...]
Subject: [ham_amplifiers] Migration to Groups.Io Hello to the Brain Trust! The following group has been set up and paid for...?/g/ham-amplifiers The Auto-Migration should happen any day and as soon as that is complete I'll kill this one. A couple of people have already figured it out and signed up. As a side note, they hold you hostage by making you pay for a yearly subscription ($220.00) to use their services, which I paid. While nobody will ever be required to pay to be a member here, any donation to help offset the cost would be appreciated. 100% of the money will be used exclusively for this group and once we reach $220 I'll let everyone know. I'm dino@... on PayPal and @DinoDarling on Venmo. Thanks!? Dino - KX6D
|
Leigh Turner
Mike
