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Re: AL-80B Transformer Solution now that Ameritron is closing?

 

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Looking in the MFJ catalog, it looks like the xmfr ( part @406-1109-2C ) has the following ratings:

Secondary:

1047 vac? 0.1Adc

22 vac? 1.5Adc? CT

5.2Vac? 15Adc? CT

Primary:? 90 - 140?? 205 - 250? w/buck-boost winding

Hope this helps.? 73? Andy? K9ATX?



On 12/31/2024 3:55 PM, Alek Petkovic via groups.io wrote:

Snap!

Yes, it is a specifically designed transformer and I'm sure Tom will have the correct information on it.

73 from sunny Western Australia where we have made it into 2025.

Alek VK6APK.

On 31/12/2024 9:23 pm, Louis Parascondola via groups.io wrote:
Contact Tom W8JI, he will know for sure! ?He’s the only guy I would rely on for exact data concerning that transfomer. ?Lou




On Tuesday, December 31, 2024, 1:59 AM, Warren Holcomb (WR0S) via groups.io <wr0s@...> wrote:

I have a transformer company that might be able to assist.? Does anyone know the exact spec of the Ameritron AL-80B power transformer?? ?I'm assuming secondaries are? 9VAC @ 1.5A,? ?3.53VAC @ 15A, and 1100VAC @ .6A? ?I have dug through the manuals and can't find anything specific.? You can see the voltage doubler in the schematic though.? And if 3100 No load volts is the DC target for B+?? ?Thanks!? ?Warren? (WR0S)

-- 
"Where the Old Soo crossed the New Soo"
Duplainville, Wisconsin

Broadcastify Train Scanner:  

Youtube Channel:

Re: AL-80B Transformer Solution now that Ameritron is closing?

 

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Snap!

Yes, it is a specifically designed transformer and I'm sure Tom will have the correct information on it.

73 from sunny Western Australia where we have made it into 2025.

Alek VK6APK.

On 31/12/2024 9:23 pm, Louis Parascondola via groups.io wrote:

Contact Tom W8JI, he will know for sure! ?He’s the only guy I would rely on for exact data concerning that transfomer. ?Lou




On Tuesday, December 31, 2024, 1:59 AM, Warren Holcomb (WR0S) via groups.io <wr0s@...> wrote:

I have a transformer company that might be able to assist.? Does anyone know the exact spec of the Ameritron AL-80B power transformer?? ?I'm assuming secondaries are? 9VAC @ 1.5A,? ?3.53VAC @ 15A, and 1100VAC @ .6A? ?I have dug through the manuals and can't find anything specific.? You can see the voltage doubler in the schematic though.? And if 3100 No load volts is the DC target for B+?? ?Thanks!? ?Warren? (WR0S)
Re: AL-80B Transformer Solution now that Ameritron is closing?

 

Contact Tom W8JI, he will know for sure! ?He’s the only guy I would rely on for exact data concerning that transfomer. ?Lou




On Tuesday, December 31, 2024, 1:59 AM, Warren Holcomb (WR0S) via groups.io <wr0s@...> wrote:

I have a transformer company that might be able to assist.? Does anyone know the exact spec of the Ameritron AL-80B power transformer?? ?I'm assuming secondaries are? 9VAC @ 1.5A,? ?3.53VAC @ 15A, and 1100VAC @ .6A? ?I have dug through the manuals and can't find anything specific.? You can see the voltage doubler in the schematic though.? And if 3100 No load volts is the DC target for B+?? ?Thanks!? ?Warren? (WR0S)
Re: AL-80B Transformer Solution now that Ameritron is closing?

 

Would Ameritron forward there suppliers info?

On Tuesday, December 31, 2024 at 01:59:13 AM EST, Warren Holcomb (WR0S) via groups.io <wr0s@...> wrote:


I have a transformer company that might be able to assist.? Does anyone know the exact spec of the Ameritron AL-80B power transformer?? ?I'm assuming secondaries are? 9VAC @ 1.5A,? ?3.53VAC @ 15A, and 1100VAC @ .6A? ?I have dug through the manuals and can't find anything specific.? You can see the voltage doubler in the schematic though.? And if 3100 No load volts is the DC target for B+?? ?Thanks!? ?Warren? (WR0S)
AL-80B Transformer Solution now that Ameritron is closing?

 

I have a transformer company that might be able to assist.? Does anyone know the exact spec of the Ameritron AL-80B power transformer?? ?I'm assuming secondaries are? 9VAC @ 1.5A,? ?3.53VAC @ 15A, and 1100VAC @ .6A? ?I have dug through the manuals and can't find anything specific.? You can see the voltage doubler in the schematic though.? And if 3100 No load volts is the DC target for B+?? ?Thanks!? ?Warren? (WR0S)
Re: GG Amplifiers Bias Cut Off

 

Alek, QRO Technology made that same mistake with the fan speed switching on the 2500 amp. ?It eventually ruins the switch. ?In one case I had the warm up timer would reset every time the guy changed the fsn speed. ?To solve the problem I properly wired the system.




On Monday, December 30, 2024, 7:16 AM, mike repinski via groups.io <mikflathead@...> wrote:

I know that the W6PO amps I built for 2 meters and 220 mhz shorted out the resistor for operating bias. But he was a smart guy. :)? Some paperwork I have from? K9EK does the same thing.

On Sunday, December 29, 2024 at 09:38:56 PM EST, Alek Petkovic via groups.io <vk6apk@...> wrote:


In older commercial grounded grid amplifiers, it is common to see a
cahngeover relay used to switch between a zener diode or similar bias
regulator and a bias cut off resistor.

My question is, why did they do it like that?

To me, it is bad engineering, in that during the change of state between
transmit and receive, there is a short period where there is neither cut
off nor idle current bias applied. OK, it is a very short period but it
happens.

In my view, it is surely better to have the bias cut off resistor
permanently in series with the bias regulator and simply have the relay
contact short the resistor when the amplifier is keyed. That way, that
small period of open circuit bias can never occur. Why couldn't the
designers of these old amps see the simplicity and sense of doing this?

73, Alek VK6APK.
Re: GG Amplifiers Bias Cut Off

 

I know that the W6PO amps I built for 2 meters and 220 mhz shorted out the resistor for operating bias. But he was a smart guy. :)? Some paperwork I have from? K9EK does the same thing.

On Sunday, December 29, 2024 at 09:38:56 PM EST, Alek Petkovic via groups.io <vk6apk@...> wrote:


In older commercial grounded grid amplifiers, it is common to see a
cahngeover relay used to switch between a zener diode or similar bias
regulator and a bias cut off resistor.

My question is, why did they do it like that?

To me, it is bad engineering, in that during the change of state between
transmit and receive, there is a short period where there is neither cut
off nor idle current bias applied. OK, it is a very short period but it
happens.

In my view, it is surely better to have the bias cut off resistor
permanently in series with the bias regulator and simply have the relay
contact short the resistor when the amplifier is keyed. That way, that
small period of open circuit bias can never occur. Why couldn't the
designers of these old amps see the simplicity and sense of doing this?

73, Alek VK6APK.
GG Amplifiers Bias Cut Off

 

In older commercial grounded grid amplifiers, it is common to see a cahngeover relay used to switch between a zener diode or similar bias regulator and a bias cut off resistor.

My question is, why did they do it like that?

To me, it is bad engineering, in that during the change of state between transmit and receive, there is a short period where there is neither cut off nor idle current bias applied. OK, it is a very short period but it happens.

In my view, it is surely better to have the bias cut off resistor permanently in series with the bias regulator and simply have the relay contact short the resistor when the amplifier is keyed. That way, that small period of open circuit bias can never occur. Why couldn't the designers of these old amps see the simplicity and sense of doing this?

73, Alek VK6APK.
Re: TL-922 tube filament voltage.

 

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Before retiring and while still active in the field, precision

D.M.M.’s were important, not in themselves, per se, but as

a reference point in any possible report ensuing from having

to have employed a meter at all.

?

Being able to say ” “a Fluke 89-4” multimeter confirmed the

proper voltage,”” would immediately be acceptable as an

observation deemed correct.

?

So there in and there out different Fluke meters were supplied

to people doing these reports, and they were deemed calibrated

when received, but no Proof of Performance quality checks were

ever specified to even see if those were correct…

?

As the years wore by the collection of those ubiquitous yellow

rubber handhelds accumulated. I remember the last time I

sent in the ’89 to the factory, only to be told:

  1. We don’t have any more parts to fit the meter, and,
  2. We can’t do any minor repairs, and,
  3. We can’t do any more calibrations.

?

Well, the battery holders were turning to cheese and in order to

get the meter to come up it was necessary to jury-rig a connection

between the AA cell compartment and the meter, proper.

?

Then, the AA battery holder hardware turned to cheese on the ‘289,

and Lo! and Behold!? “ Fugeddaboudit.” There are no parts to fix it.

?

There are other meters, newer models, and they seem to be working,

and when setting up a bench to observe a “standard,” the readings

are all over the place. Fluke. Thousands of dollars to buy and then,

when the rubber needs to meet the road, they can no longer be trusted.

?

A case-in-point:? Recently an experiment regarding the various measurements

of signals and amplitudes came up. Both the ’89 and the ‘289 can be

configured for dBm, and even the reference load values adjusted for

a wide range of activity, like 50 or 300 or 600 ohms.

?

Even with a new set of AA cells, and a proper warmup, using the meters

to show what the new bench supply says is “something” in the 50 ohm

dBm Land, the readings are different. Not too, too different, but still not

right on the money as Fluke would have been relied upon to produce.

?

So yes, there are a new set of DMM’s coming out that are Orders of

Magnitude cheaper than new Flukes, and best, is that many of them

come with certificates of calibration right in the box.

?

Forums like the eev blog compare quality and consistency to test

gear day after day. They are the first to raise a ruckus when something

is squirrely.

?

Hal Mandel

W4HBM
Re: G3SEK Tetrode Boards documentation

 

GM3SEK? Here is a link that turned up.
No longer sold it seems, and a quick search for gerbers turned up nothing for me.?
The schematic is in the manual so one could do a board run if so inclined.?
Bob H N9NRW
?
http://www.ifwtech.co.uk/g3sek/
Re: Amp modification

 

http://www.ifwtech.co.uk/g3sek/
Re: G3SEK Tetrode Boards documentation

 

Attached to this email are the manuals for the G3SEK tetrode and triode boards as well as the tetrode board design documentation. Maybe the moderators can add these to the group files section.

triode-manual.pdf
triode-manual.pdf
tetrode-manual.pdf
tetrode-manual.pdf
power and protection for modern tetrodes.pdf
power and protection for modern tetrodes.pdf

G3SEK Tetrode Boards documentation

 

Mike,

Try this:



73 Bill N4LG

At 11:17 AM 12/28/2024, Mike Peace via groups.io wrote:
Hi,?
Would anyone have the G3SEK schematic and PCB drawings for download?

The link seems to be broken for me:
<>

Cheers,
Mike Peace
VK6ADA


On Sat, Dec 28, 2024 at 9:52?�?AM Mike WB2FKO via <>groups.io <mph=<mailto:[email protected]>[email protected]> wrote:
The tetrode boards aren?�?t particularly complicated if you only implement the screen current trip. On my tetrode amplifier, I eliminated the control grid current trip and ALC circuitry. Their primary purpose is providing regulated screen voltage with most of the larger components placed off the boards. The schematic diagrams are still available on G3SEK?�?s website so spinning up an equivalent set of PCBs — perhaps just one PCB is all that?�?s needed ??�” should not be difficult.

Mike WB2FKO

On Dec 27, 2024, at 9:03?�?PM, Billy Pickering via <>groups.io <pickeringw=<mailto:[email protected]>[email protected]> wrote:

???
Well, I was lucky enough to pick up a Henry Tempo 2006 that did not have any tubes. Yes, 3CX400A7 tubes are expensive so we were looking into modifying it to run 2 or 3 4CX250B tubes instead. I know we need to have screen power for these tubes, and was wondering if anyone was currently making the GM3SEK tetrode control boards. I guess we could come up with something from scratch, but those boards are really nice.
?
I guess if it really come down to it, we could modify to run the single 3CX800A7 we have, but not sure if the tube is any good as it was pulled from a commercial unit.
Re: Amp modification

 

Hi,?
Would anyone have the G3SEK schematic and PCB drawings for download?

The link seems to be broken for me:

Cheers,
Mike Peace
VK6ADA


On Sat, Dec 28, 2024 at 9:52?AM Mike WB2FKO via <mph=[email protected]> wrote:
The tetrode boards aren’t particularly complicated if you only implement the screen current trip. On my tetrode amplifier, I eliminated the control grid current trip and ALC circuitry. Their primary purpose is providing regulated screen voltage with most of the larger components placed off the boards. The schematic diagrams are still available on G3SEK’s website so spinning up an equivalent set of PCBs — perhaps just one PCB is all that’s needed — should not be difficult.

Mike WB2FKO

On Dec 27, 2024, at 9:03?PM, Billy Pickering via <pickeringw=[email protected]> wrote:

?
Well, I was lucky enough to pick up a Henry Tempo 2006 that did not have any tubes. Yes, 3CX400A7 tubes are expensive so we were looking into modifying it to run 2 or 3 4CX250B tubes instead. I know we need to have screen power for these tubes, and was wondering if anyone was currently making the GM3SEK tetrode control boards. I guess we could come up with something from scratch, but those boards are really nice.
?
I guess if it really come down to it, we could modify to run the single 3CX800A7 we have, but not sure if the tube is any good as it was pulled from a commercial unit.
Re: Amp modification

 

I have ran into a couple of those online. Wanted to put one in my Thunderbolt,
as it uses the gas filled tubes to regulate the screen, but I was gonna try a string of Zeners
soldered into an old tube socket as an experiment.

Then I learned if you over drive the input of the amp with too much RF,
you will get screen current and the result is IMD splatter.

The new fancy amps seem to be able to detect this, and they disable the tube
somehow - probably by putting the tube into cutoff via the control grid I guess.

--
Steve Hearns [ KA2PTE ]
Technotronic Dimensions, VT [USA]
WWW.TECHNOTRONIC-DIMENSIONS.COM
E-Mail: Steve@...

----- Original Message -----
From: "Mike WB2FKO" <mph@...>
To: <[email protected]>
Sent: Friday, December 27, 2024 10:19 PM
Subject: Re: [ham-amplifiers] Amp modification


The tetrode boards aren?�?t particularly complicated if you only implement the screen current trip. On my tetrode amplifier, I eliminated the control grid current trip and ALC circuitry. Their primary purpose is providing regulated screen voltage with most of the larger components placed off the boards. The schematic diagrams are still available on G3SEK?�?s website so spinning up an equivalent set of PCBs ?�” perhaps just one PCB is all that?�?s needed ?�” should not be difficult.


Mike WB2FKO


On Dec 27, 2024, at 9:03?�?PM, Billy Pickering via groups.io <pickeringw@...> wrote:


???
Well, I was lucky enough to pick up a Henry Tempo 2006 that did not have any tubes. Yes, 3CX400A7 tubes are expensive so we were looking into modifying it to run 2 or 3 4CX250B tubes instead. I know we need to have screen power for these tubes, and was wondering if anyone was currently making the GM3SEK tetrode control boards. I guess we could come up with something from scratch, but those boards are really nice.

I guess if it really come down to it, we could modify to run the single 3CX800A7 we have, but not sure if the tube is any good as it was pulled from a commercial unit.
Re: Amp modification

 

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The tetrode boards aren’t particularly complicated if you only implement the screen current trip. On my tetrode amplifier, I eliminated the control grid current trip and ALC circuitry. Their primary purpose is providing regulated screen voltage with most of the larger components placed off the boards. The schematic diagrams are still available on G3SEK’s website so spinning up an equivalent set of PCBs — perhaps just one PCB is all that’s needed — should not be difficult.

Mike WB2FKO

On Dec 27, 2024, at 9:03?PM, Billy Pickering via groups.io <pickeringw@...> wrote:

?
Well, I was lucky enough to pick up a Henry Tempo 2006 that did not have any tubes. Yes, 3CX400A7 tubes are expensive so we were looking into modifying it to run 2 or 3 4CX250B tubes instead. I know we need to have screen power for these tubes, and was wondering if anyone was currently making the GM3SEK tetrode control boards. I guess we could come up with something from scratch, but those boards are really nice.
?
I guess if it really come down to it, we could modify to run the single 3CX800A7 we have, but not sure if the tube is any good as it was pulled from a commercial unit.
Re: Amp modification

 

Can't beat the simplicity of a triode amplifier.

On Saturday, December 28, 2024 at 10:37:45 AM EST, mike repinski via groups.io <mikflathead@...> wrote:


Sell your 4CX250's and purchase the 3CX400's ?

On Saturday, December 28, 2024 at 10:35:06 AM EST, Billy Pickering via groups.io <pickeringw@...> wrote:


Main reason for looking into the 4CX250 is I have a ton of them, like 10-12 of them, sockets and chimneys as well.
?
My father-in-law who is also my elmer built an amp around the RF deck of a KWS-1 that had been destroyed in shipping which is why we have so many of those tubes. The Henry has the power supply in it and everything else, just not the tubes.
Re: Amp modification

 

Re: Amp modification

 

Sell your 4CX250's and purchase the 3CX400's ?

On Saturday, December 28, 2024 at 10:35:06 AM EST, Billy Pickering via groups.io <pickeringw@...> wrote:


Main reason for looking into the 4CX250 is I have a ton of them, like 10-12 of them, sockets and chimneys as well.
?
My father-in-law who is also my elmer built an amp around the RF deck of a KWS-1 that had been destroyed in shipping which is why we have so many of those tubes. The Henry has the power supply in it and everything else, just not the tubes.
Re: Amp modification

 

Main reason for looking into the 4CX250 is I have a ton of them, like 10-12 of them, sockets and chimneys as well.
?
My father-in-law who is also my elmer built an amp around the RF deck of a KWS-1 that had been destroyed in shipping which is why we have so many of those tubes. The Henry has the power supply in it and everything else, just not the tubes.
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