FW: K3 and StepIR/Icom PW-1

[Adam Farson]

Hi Greg,

The PW1 uses the ALC loop as an essential part of its protective subsystem,
as described in the service manual excerpt  which I sent you. Any one of
several anomalous operating conditions (including over-drive and load
mismatch) will pull down the ALC line to reduce the drive. This is the
amplifier's first line of defence.

I would never put an expensive piece of equipment such as the PW1 at risk by
connecting it to an exciter without a fully-functional ALC loop.

Cheers for now, 73,
Adam VA7OJ/AB4OJ

-----Original Message-----
From: Greg - N4CC [mailto:[hidden email]]
Sent: 7-Sep-08 19:05
To: Adam Farson
Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1

I'm using the K3 with a PW-1 and the beauty of it is you don't need the ALC
if you use the K3's capacity to store the power level (drive
level) for each band.  Obviously if you use the K3 barefoot at 100 watts you
would have to be careful to turn it back down with the amp but I just leave
it at the saved settings that I have established for output for each band.
The proper drive level does vary somewhat by band.  You are right about the
ALC ..the K3 ALC is not compatible with the PW-1 and you should not connect
the ALC line between the two.  73 de Greg

At 09:08 PM 9/7/2008, you wrote:

>  Hi Tom,
>
>The K3 should not be used as an exciter for the PW1 unless the polarity
>of its external ALC input has been changed from positive-going
>(original) to negative-going (range 0 to -4V). Failure to heed this
>warning will result in extensive damage to the PW1, necessitating
>costly repairs (as much as
>$1800!)
>
>http://www.ab4oj.com/icom/main.html#alc
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>

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[Greg - N4CC]

Adam -- I guess it depends on the user.  Certainly having the ALC
connected (if it were compatible) would be preferred...but my point
is that saying " the K3 should not be used as an exciter for the
PW-1" [without ALC] is not entirely accurate.  it is possible to use
the PW-1 without ALC.  It can be done and done quite safely.  Granted
you lose a measure of protection but if you use the K3 as I do --
where it recalls the drive setting by band, a unique feature of the
K3 -- it is less likely that not having the ALC connected will ever
be an issue.   If you change the power settings frequently and are
not careful to return them to the desired drive level when operating
the amplifier then your chance of damaging the amp increases without
the ALC.  Cheers.  73 de Greg

At 10:53 PM 9/7/2008, you wrote:

>Hi Greg,
>
>The PW1 uses the ALC loop as an essential part of its protective subsystem,
>as described in the service manual excerpt  which I sent you. Any one of
>several anomalous operating conditions (including over-drive and load
>mismatch) will pull down the ALC line to reduce the drive. This is the
>amplifier's first line of defence.
>
>I would never put an expensive piece of equipment such as the PW1 at risk by
>connecting it to an exciter without a fully-functional ALC loop.
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>
>-----Original Message-----
>From: Greg - N4CC [mailto:[hidden email]]
>Sent: 7-Sep-08 19:05
>To: Adam Farson
>Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1
>
>I'm using the K3 with a PW-1 and the beauty of it is you don't need the ALC
>if you use the K3's capacity to store the power level (drive
>level) for each band.  Obviously if you use the K3 barefoot at 100 watts you
>would have to be careful to turn it back down with the amp but I just leave
>it at the saved settings that I have established for output for each band.
>The proper drive level does vary somewhat by band.  You are right about the
>ALC ..the K3 ALC is not compatible with the PW-1 and you should not connect
>the ALC line between the two.  73 de Greg
>
>At 09:08 PM 9/7/2008, you wrote:
> >  Hi Tom,
> >
> >The K3 should not be used as an exciter for the PW1 unless the polarity
> >of its external ALC input has been changed from positive-going
> >(original) to negative-going (range 0 to -4V). Failure to heed this
> >warning will result in extensive damage to the PW1, necessitating
> >costly repairs (as much as
> >$1800!)
> >
> >http://www.ab4oj.com/icom/main.html#alc
> >
> >Cheers for now, 73,
> >Adam VA7OJ/AB4OJ
> >
>
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>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
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>
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>Elecraft web page: http://www.elecraft.com

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[Adam Farson]

Hi Greg,

Still, I would feel a lot more comfortable were Elecraft to correct the
polarity of their external ALC input to the negative-going industry
standard. I understand that this modification is presently underway.

Given the growing popularity of solid-state amplifiers (which all provide
negative-going ALC voltage, to my knowledge) I can think of no rational
reason for not making this change.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


-----Original Message-----
From: Greg - N4CC [mailto:[hidden email]]
Sent: 7-Sep-08 21:00
To: Adam Farson
Cc: [hidden email]
Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1

Adam -- I guess it depends on the user.  Certainly having the ALC connected
(if it were compatible) would be preferred...but my point is that saying "
the K3 should not be used as an exciter for the PW-1" [without ALC] is not
entirely accurate.  it is possible to use the PW-1 without ALC.  It can be
done and done quite safely.  Granted you lose a measure of protection but if
you use the K3 as I do -- where it recalls the drive setting by band, a
unique feature of the
K3 -- it is less likely that not having the ALC connected will ever
be an issue.   If you change the power settings frequently and are
not careful to return them to the desired drive level when operating the
amplifier then your chance of damaging the amp increases without the ALC.
Cheers.  73 de Greg

At 10:53 PM 9/7/2008, you wrote:

>Hi Greg,
>
>The PW1 uses the ALC loop as an essential part of its protective
>subsystem, as described in the service manual excerpt  which I sent
>you. Any one of several anomalous operating conditions (including
>over-drive and load
>mismatch) will pull down the ALC line to reduce the drive. This is the
>amplifier's first line of defence.
>
>I would never put an expensive piece of equipment such as the PW1 at
>risk by connecting it to an exciter without a fully-functional ALC loop.
>
>Cheers for now, 73,
>Adam VA7OJ/AB4OJ
>
>-----Original Message-----
>From: Greg - N4CC [mailto:[hidden email]]
>Sent: 7-Sep-08 19:05
>To: Adam Farson
>Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1
>
>I'm using the K3 with a PW-1 and the beauty of it is you don't need the
>ALC if you use the K3's capacity to store the power level (drive
>level) for each band.  Obviously if you use the K3 barefoot at 100
>watts you would have to be careful to turn it back down with the amp
>but I just leave it at the saved settings that I have established for

output for each band.

>The proper drive level does vary somewhat by band.  You are right about
>the ALC ..the K3 ALC is not compatible with the PW-1 and you should not
>connect the ALC line between the two.  73 de Greg
>
>At 09:08 PM 9/7/2008, you wrote:
> >  Hi Tom,
> >
> >The K3 should not be used as an exciter for the PW1 unless the
> >polarity of its external ALC input has been changed from
> >positive-going
> >(original) to negative-going (range 0 to -4V). Failure to heed this
> >warning will result in extensive damage to the PW1, necessitating
> >costly repairs (as much as
> >$1800!)
> >
> >http://www.ab4oj.com/icom/main.html#alc
> >
> >Cheers for now, 73,
> >Adam VA7OJ/AB4OJ
> >
>

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[Jim Brown-10]

On Mon, 08 Sep 2008 00:00:06 -0400, Greg - N4CC wrote:

>Certainly having the ALC
>connected (if it were compatible) would be preferred..

It MAY be true for this amp, but at least some other amp mfrs advise
against the use of ALC with their amps. They say that modern amps
work fine without ALC if the operator is smart enough to turn down
the drive so that the amp is operating properly (and an operator
that isn't shouldn't be on the ham bands), and that depending on ALC
to keep the drive level down as a routine matter will cause higher
distortion than if the ALC was not used. Ten Tec is one of the mfrs
that has published this in their manuals for at least 25 years.

Now, I certainly do see the value of ALC as a protection mechanism
in the case of a failure that causes serious antenna mismatch, but
there are other ways to achieve that.

73,

Jim Brown K9YC


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[Jerry Flanders]

I once blew up an unprotected amplifier's output circuit when a flaky
antenna feed line opened with 1500 watts RTTY applied.  Prior to
that, I didn't think I needed anything more than a hand on the drive
level control to keep my amp safe.

Now I make sure the ALC is there so the amp can cut that drive within
milliseconds if the antenna opens up again.

The K3 ALC fix is available from Elecraft. It works.

Jerry W4UK

At 12:00 AM 9/8/2008, Greg - N4CC wrote:

>Adam -- I guess it depends on the user.  Certainly having the ALC
>connected (if it were compatible) would be preferred...but my point
>is that saying " the K3 should not be used as an exciter for the
>PW-1" [without ALC] is not entirely accurate.  it is possible to use
>the PW-1 without ALC.  It can be done and done quite
>safely.  Granted you lose a measure of protection but if you use the
>K3 as I do -- where it recalls the drive setting by band, a unique
>feature of the K3 -- it is less likely that not having the ALC
>connected will ever be an issue.   If you change the power settings
>frequently and are not careful to return them to the desired drive
>level when operating the amplifier then your chance of damaging the
>amp increases without the ALC.  Cheers.  73 de Greg
>
>At 10:53 PM 9/7/2008, you wrote:
>>Hi Greg,
>>
>>The PW1 uses the ALC loop as an essential part of its protective subsystem,
>>as described in the service manual excerpt  which I sent you. Any one of
>>several anomalous operating conditions (including over-drive and load
>>mismatch) will pull down the ALC line to reduce the drive. This is the
>>amplifier's first line of defence.
>>
>>I would never put an expensive piece of equipment such as the PW1 at risk by
>>connecting it to an exciter without a fully-functional ALC loop.
>>
>>Cheers for now, 73,
>>Adam VA7OJ/AB4OJ
>>
>>-----Original Message-----
>>From: Greg - N4CC [mailto:[hidden email]]
>>Sent: 7-Sep-08 19:05
>>To: Adam Farson
>>Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1
>>
>>I'm using the K3 with a PW-1 and the beauty of it is you don't need the ALC
>>if you use the K3's capacity to store the power level (drive
>>level) for each band.  Obviously if you use the K3 barefoot at 100 watts you
>>would have to be careful to turn it back down with the amp but I just leave
>>it at the saved settings that I have established for output for each band.
>>The proper drive level does vary somewhat by band.  You are right about the
>>ALC ..the K3 ALC is not compatible with the PW-1 and you should not connect
>>the ALC line between the two.  73 de Greg
>>
>>At 09:08 PM 9/7/2008, you wrote:
>> >  Hi Tom,
>> >
>> >The K3 should not be used as an exciter for the PW1 unless the polarity
>> >of its external ALC input has been changed from positive-going
>> >(original) to negative-going (range 0 to -4V). Failure to heed this
>> >warning will result in extensive damage to the PW1, necessitating
>> >costly repairs (as much as
>> >$1800!)
>> >
>> >http://www.ab4oj.com/icom/main.html#alc
>> >
>> >Cheers for now, 73,
>> >Adam VA7OJ/AB4OJ
>> >
>>
>>_______________________________________________

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[Adam Farson]

Hi Jerry,

Glad to hear that the fix has now been implemented.

Cheers for now, 73,
Adam VA7OJ/AB4OJ
 

-----Original Message-----
From: Jerry Flanders [mailto:[hidden email]]
Sent: 7-Sep-08 21:40
To: Greg - N4CC; Adam Farson
Cc: [hidden email]
Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1

I once blew up an unprotected amplifier's output circuit when a flaky
antenna feed line opened with 1500 watts RTTY applied.  Prior to that, I
didn't think I needed anything more than a hand on the drive level control
to keep my amp safe.

Now I make sure the ALC is there so the amp can cut that drive within
milliseconds if the antenna opens up again.

The K3 ALC fix is available from Elecraft. It works.

Jerry W4UK

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[Doug Faunt N6TQS [phone]]

You've not been paying enough attention:
EXALCMDKT  K3 Negative External ALC Mod Kit $10.00

and

http://www.elecraft.com/K3/mods/K3ALCMod.pdf

73, doug

As usual, Elecraft is reponsive.


   From: "Adam Farson" <[hidden email]>
   Date: Sun, 7 Sep 2008 21:13:49 -0700

   Hi Greg,

   Still, I would feel a lot more comfortable were Elecraft to correct the
   polarity of their external ALC input to the negative-going industry
   standard. I understand that this modification is presently underway.

   Given the growing popularity of solid-state amplifiers (which all provide
   negative-going ALC voltage, to my knowledge) I can think of no rational
   reason for not making this change.

   Cheers for now, 73,
   Adam VA7OJ/AB4OJ


   -----Original Message-----
   From: Greg - N4CC [mailto:[hidden email]]
   Sent: 7-Sep-08 21:00
   To: Adam Farson
   Cc: [hidden email]
   Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1

   Adam -- I guess it depends on the user.  Certainly having the ALC connected
   (if it were compatible) would be preferred...but my point is that saying "
   the K3 should not be used as an exciter for the PW-1" [without ALC] is not
   entirely accurate.  it is possible to use the PW-1 without ALC.  It can be
   done and done quite safely.  Granted you lose a measure of protection but if
   you use the K3 as I do -- where it recalls the drive setting by band, a
   unique feature of the
   K3 -- it is less likely that not having the ALC connected will ever
   be an issue.   If you change the power settings frequently and are
   not careful to return them to the desired drive level when operating the
   amplifier then your chance of damaging the amp increases without the ALC.
   Cheers.  73 de Greg

   At 10:53 PM 9/7/2008, you wrote:
   >Hi Greg,
   >
   >The PW1 uses the ALC loop as an essential part of its protective
   >subsystem, as described in the service manual excerpt  which I sent
   >you. Any one of several anomalous operating conditions (including
   >over-drive and load
   >mismatch) will pull down the ALC line to reduce the drive. This is the
   >amplifier's first line of defence.
   >
   >I would never put an expensive piece of equipment such as the PW1 at
   >risk by connecting it to an exciter without a fully-functional ALC loop.
   >
   >Cheers for now, 73,
   >Adam VA7OJ/AB4OJ
   >
   >-----Original Message-----
   >From: Greg - N4CC [mailto:[hidden email]]
   >Sent: 7-Sep-08 19:05
   >To: Adam Farson
   >Subject: Re: FW: [Elecraft] K3 and StepIR/Icom PW-1
   >
   >I'm using the K3 with a PW-1 and the beauty of it is you don't need the
   >ALC if you use the K3's capacity to store the power level (drive
   >level) for each band.  Obviously if you use the K3 barefoot at 100
   >watts you would have to be careful to turn it back down with the amp
   >but I just leave it at the saved settings that I have established for
   output for each band.
   >The proper drive level does vary somewhat by band.  You are right about
   >the ALC ..the K3 ALC is not compatible with the PW-1 and you should not
   >connect the ALC line between the two.  73 de Greg
   >
   >At 09:08 PM 9/7/2008, you wrote:
   > >  Hi Tom,
   > >
   > >The K3 should not be used as an exciter for the PW1 unless the
   > >polarity of its external ALC input has been changed from
   > >positive-going
   > >(original) to negative-going (range 0 to -4V). Failure to heed this
   > >warning will result in extensive damage to the PW1, necessitating
   > >costly repairs (as much as
   > >$1800!)
   > >
   > >http://www.ab4oj.com/icom/main.html#alc
   > >
   > >Cheers for now, 73,
   > >Adam VA7OJ/AB4OJ
   > >
   >

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