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[KPA500] incredible hum from PA

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kevino z

[KPA500] incredible hum from PA

Just got my KPA500 and KAT500. I hooked the PA up to 240v (well, my Mains are 248v), so I made sure the assembled PA has the yellow transformer tap, from the factory.
When I engage the amp, there is a crazy buzz. I use a KPA500 at work, but it is on 120v and I never hear this buzz. Before I swap fuses, and switch over to 120v to test, does anyone else have this issue?
The KPA500 is hooked up to a KX3/KXPA100 combo, just in case someone would ask.
Thanks
-Kevin (KK4YEL)

No trees were killed in the sending of this message. However, a large number of electrons were terribly inconvenienced !
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W1GO (Joe)

Re: [KPA500] incredible hum from PA

Kevin,

Yes. had the problem. Crazy loud hum / buzz. Bad transformer I was told. All quiet on the eastern front now. If it is a bad transformer it can be fixed but you’ll have to eat the shipping charge.

Joe
W1GO

> On Dec 19, 2016, at 9:10 PM, kevino z <[hidden email]> wrote:
>
> Just got my KPA500 and KAT500. I hooked the PA up to 240v (well, my Mains are 248v), so I made sure the assembled PA has the yellow transformer tap, from the factory.
> When I engage the amp, there is a crazy buzz. I use a KPA500 at work, but it is on 120v and I never hear this buzz. Before I swap fuses, and switch over to 120v to test, does anyone else have this issue?
> The KPA500 is hooked up to a KX3/KXPA100 combo, just in case someone would ask.
> Thanks
> -Kevin (KK4YEL)
>
>
> No trees were killed in the sending of this message. However, a large number of electrons were terribly inconvenienced !
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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kevino z

Re: [KPA500] incredible hum from PA

Thanks Ron. I'll open it up and measure it with a torque wrench. Then wait for Elecraft tech support to call back. Sometimes it's a drag living on the East Coast :-(
-Kevin (KK4YEL)

No trees were killed in the sending of this message. However, a large number of electrons were terribly inconvenienced !

> On Dec 19, 2016, at 22:53, Ron D'Eau Claire <[hidden email]> wrote:
>
> Joe might be right but contact Tech Support first. The transformer is held in place with a single large bolt through the center (it is a torodial transformer). If that bolt is not tightened properly the magnetic field will produce a huge vibration. Even if you did not build the amp from the kit, it's a pretty simple job to tighten that bolt. Tech Support can lead you through the process. It is also described in the kit assembly manual available on the Elecraft web site here;
> http://www.elecraft.com/manual/E740149%20KPA500%20Kit%20Assembly%20Manual%20Rev%20F6.pdf
>
> See pages 36 and 37.
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of W1GO (Joe)
> Sent: Monday, December 19, 2016 6:19 PM
> To: kevino z
> Cc: Elecraft Reflector
> Subject: Re: [Elecraft] [KPA500] incredible hum from PA
>
> Kevin,
>
> Yes. had the problem. Crazy loud hum / buzz. Bad transformer I was told. All quiet on the eastern front now. If it is a bad transformer it can be fixed but you’ll have to eat the shipping charge.
>
> Joe
> W1GO
>
>> On Dec 19, 2016, at 9:10 PM, kevino z <[hidden email]> wrote:
>>
>> Just got my KPA500 and KAT500. I hooked the PA up to 240v (well, my Mains are 248v), so I made sure the assembled PA has the yellow transformer tap, from the factory.
>> When I engage the amp, there is a crazy buzz. I use a KPA500 at work, but it is on 120v and I never hear this buzz. Before I swap fuses, and switch over to 120v to test, does anyone else have this issue?
>> The KPA500 is hooked up to a KX3/KXPA100 combo, just in case someone would ask.
>> Thanks
>> -Kevin (KK4YEL)
>>
>>
>> No trees were killed in the sending of this message. However, a large number of electrons were terribly inconvenienced !
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net Please help support this email
>> list: http://www.qsl.net/donate.html Message delivered to
>> [hidden email]
>
> ______________________________________________________________
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>

Charlie T, K3ICH

Re: [KPA500] incredible hum from PA

"No trees were killed in the sending of this message. However, a large
number of electrons were terribly inconvenienced !"

Yeah, but you have to realize, electrons LIKE to run around madly. They
LIVE for the opportunity to be driven by that strange (to them)
electromotive force, regardless of whether it's in one direction (DC) or
back and forth (AC), just as horses luv to run.
They live basically a very nomadic life, jumping from one nucleus to
another. They get sluggish if not driven regularly. This is why old stock
vacuum tubes can fail while just sitting on the shelf.
Electrons also appreciate the applause as horses do when they perform, but
seldom get to enjoy it. So, when you make them run, at least provide a
little noise so that know they're well liked. Hmmm, maybe THAT"s why the
transformer hums?

More to the point of the subject, I wonder if it would have been possible to
use a brass bolt or maybe even nylon mounting hardware for the big toroid?
Probably not worth the effort is a simple re-tightening can fix it.
( You'll just have to provide some outside method of showing your
appreciation to the electrons for their efforts.)

73 Charlie k3ICH

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kevino z

Re: [KPA500] incredible hum from PA

Nice!
Sadly, torquing it down to the spec (it was assembled by Elecraft just under the spec, by the way) made zero difference. But your post made me smile so thank you. Haven't done that since I got the amp powered on.

-Kevin (KK4YEL)

> On Dec 20, 2016, at 07:42, Charlie T, K3ICH <[hidden email]> wrote:
>
>
> "No trees were killed in the sending of this message. However, a large
> number of electrons were terribly inconvenienced !"
>
> Yeah, but you have to realize, electrons LIKE to run around madly. They
> LIVE for the opportunity to be driven by that strange (to them)
> electromotive force, regardless of whether it's in one direction (DC) or
> back and forth (AC), just as horses luv to run.
> They live basically a very nomadic life, jumping from one nucleus to
> another. They get sluggish if not driven regularly. This is why old stock
> vacuum tubes can fail while just sitting on the shelf.
> Electrons also appreciate the applause as horses do when they perform, but
> seldom get to enjoy it. So, when you make them run, at least provide a
> little noise so that know they're well liked. Hmmm, maybe THAT"s why the
> transformer hums?
>
> More to the point of the subject, I wonder if it would have been possible to
> use a brass bolt or maybe even nylon mounting hardware for the big toroid?
> Probably not worth the effort is a simple re-tightening can fix it.
> ( You'll just have to provide some outside method of showing your
> appreciation to the electrons for their efforts.)
>
> 73 Charlie k3ICH
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

David Olean

Re: [KPA500] incredible hum from PA

In reply to this post by Charlie T, K3ICH

Wow, another person who ascribes to the theory of Electron Psychology. I
have long believed that electrons had feelings and needs. You can
explain coax cable losses very easily. All the electrons start down the
inner wire, but soon start to wonder if they will ever get to the end.
The longer the cable is, the more they lose confidence and either stop
or turn around. We used to sit around in the lab and come up with
electron psychology reasons for all sorts of situations.

K1WHS

On 12/20/2016 12:40 PM, Charlie T, K3ICH wrote:

> "No trees were killed in the sending of this message. However, a large
> number of electrons were terribly inconvenienced !"
>
> Yeah, but you have to realize, electrons LIKE to run around madly. They
> LIVE for the opportunity to be driven by that strange (to them)
> electromotive force, regardless of whether it's in one direction (DC) or
> back and forth (AC), just as horses luv to run.
> They live basically a very nomadic life, jumping from one nucleus to
> another. They get sluggish if not driven regularly. This is why old stock
> vacuum tubes can fail while just sitting on the shelf.
> Electrons also appreciate the applause as horses do when they perform, but
> seldom get to enjoy it. So, when you make them run, at least provide a
> little noise so that know they're well liked. Hmmm, maybe THAT"s why the
> transformer hums?
>
> More to the point of the subject, I wonder if it would have been possible to
> use a brass bolt or maybe even nylon mounting hardware for the big toroid?
> Probably not worth the effort is a simple re-tightening can fix it.
> ( You'll just have to provide some outside method of showing your
> appreciation to the electrons for their efforts.)
>
> 73 Charlie k3ICH
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Jan Ditzian

Re: [KPA500] incredible hum from PA

David,

The below statement is absolutely true. I am an industrial psychologist
(really), and we have made some discoveries about why certain industrial
processes sometimes work and sometimes don't. One of our earliest
discoveries was the answer to the question: How may psychologists does
it take to change a light bulb? The answer is that it takes only one
psychologist to make the change, but the light bulb must SINCERELY want
to change, and the process may require up to five years of weekly
50-minute sessions before the change is fully effected.

When DXing, remember that the DX LIKES the hams around you more than it
likes you, so you have to wait until the loved ones are taken care of
before you get your turn. This does not always hold when operating CW.

Jan, KX2A (the first KX2)

On 12/20/2016 10:47 AM, David Olean wrote:
> Wow, another person who ascribes to the theory of Electron Psychology.
> I have long believed that electrons had feelings and needs. You can
> explain coax cable losses very easily. All the electrons start down
> the inner wire, but soon start to wonder if they will ever get to the
> end. The longer the cable is, the more they lose confidence and either
> stop or turn around. We used to sit around in the lab and come up
> with electron psychology reasons for all sorts of situations.
>
> K1WHS

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kevino z

Re: [KPA500] incredible hum from PA

In reply to this post by Charlie T, K3ICH

Nope. I have one at work and it is quiet. Something is different with this one. As I stated in my original post, I'm confident that Elecraft will make this right. They are great folks over there.
-Kevin (KK4YEL)

-----
The problem with the world is that the intelligent people are full of doubts, while the stupid ones are full of confidence.

On Dec 20, 2016, at 12:12, Ron D'Eau Claire <[hidden email]<mailto:[hidden email]>> wrote:

I believe most of the noise comes from the steel bottom of the kpa500.

73, Ron AC7AC

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of
Charlie T, K3ICH
Sent: Tuesday, December 20, 2016 4:40 AM
To: [hidden email]<mailto:[hidden email]>
Subject: Re: [Elecraft] [KPA500] incredible hum from PA

"No trees were killed in the sending of this message. However, a large
number of electrons were terribly inconvenienced !"

Yeah, but you have to realize, electrons LIKE to run around madly. They
LIVE for the opportunity to be driven by that strange (to them)
electromotive force, regardless of whether it's in one direction (DC) or
back and forth (AC), just as horses luv to run.
They live basically a very nomadic life, jumping from one nucleus to
another. They get sluggish if not driven regularly. This is why old stock
vacuum tubes can fail while just sitting on the shelf.
Electrons also appreciate the applause as horses do when they perform, but
seldom get to enjoy it. So, when you make them run, at least provide a
little noise so that know they're well liked. Hmmm, maybe THAT"s why the
transformer hums?

More to the point of the subject, I wonder if it would have been possible to
use a brass bolt or maybe even nylon mounting hardware for the big toroid?
Probably not worth the effort is a simple re-tightening can fix it.
( You'll just have to provide some outside method of showing your
appreciation to the electrons for their efforts.)

73 Charlie k3ICH

______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html Message
delivered to [hidden email]<mailto:[hidden email]>

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Matt Murphy

Re: [KPA500] incredible hum from PA

In reply to this post by W1GO (Joe)

Mine is silent during normal use, but when someone in the house prints
something using the laser printer that is on the same circuit, the
transformer gives off a brief groan.

I don't think this means my transformer is defective, would anyone
disagree?

73,
Matt NQ6N

On Tue, Dec 20, 2016 at 11:10 AM Ron D'Eau Claire <[hidden email]> wrote:

> I believe most of the noise comes from the steel bottom of the kpa500.
>
>
>
> 73, Ron AC7AC
>
>
>
> -----Original Message-----
>
> From: Elecraft [mailto:[hidden email]] On Behalf Of
>
> Charlie T, K3ICH
>
> Sent: Tuesday, December 20, 2016 4:40 AM
>
> To: [hidden email]
>
> Subject: Re: [Elecraft] [KPA500] incredible hum from PA
>
>
>
>
>
> "No trees were killed in the sending of this message. However, a large
>
> number of electrons were terribly inconvenienced !"
>
>
>
> Yeah, but you have to realize, electrons LIKE to run around madly. They
>
> LIVE for the opportunity to be driven by that strange (to them)
>
> electromotive force, regardless of whether it's in one direction (DC) or
>
> back and forth (AC), just as horses luv to run.
>
> They live basically a very nomadic life, jumping from one nucleus to
>
> another. They get sluggish if not driven regularly. This is why old stock
>
> vacuum tubes can fail while just sitting on the shelf.
>
> Electrons also appreciate the applause as horses do when they perform, but
>
> seldom get to enjoy it. So, when you make them run, at least provide a
>
> little noise so that know they're well liked. Hmmm, maybe THAT"s why the
>
> transformer hums?
>
>
>
> More to the point of the subject, I wonder if it would have been possible
> to
>
> use a brass bolt or maybe even nylon mounting hardware for the big toroid?
>
> Probably not worth the effort is a simple re-tightening can fix it.
>
> ( You'll just have to provide some outside method of showing your
>
> appreciation to the electrons for their efforts.)
>
>
>
> 73 Charlie k3ICH
>
>
>
>
>
>
>
> ______________________________________________________________
>
> Elecraft mailing list
>
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/mmfaq.htm
>
> Post: mailto:[hidden email]
>
>
>
> This list hosted by: http://www.qsl.net
>
> Please help support this email list: http://www.qsl.net/donate.html
> Message
>
> delivered to [hidden email]
>
>
>
> ______________________________________________________________
>
> Elecraft mailing list
>
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/mmfaq.htm
>
> Post: mailto:[hidden email]
>
>
>
> This list hosted by: http://www.qsl.net
>
> Please help support this email list: http://www.qsl.net/donate.html
>
> Message delivered to [hidden email]
>
>