{Collins} Re: Speaker Wire Short on an A-4



Possibly because the reflected impedace of a short circuit is an open 
circuit? The biggest risk to a shorted tube output xfmr if the volume is 
turned up is the high voltage at the audio output tube when it sees the high 
impedance. According to "the big boys at the bicycle rack".
K0UYA
----- Original Message ----- 
From: "Bob W5EUQ" <w5euq@xxxxxxxxxxx>
To: <youngbob53@xxxxxxx>
Cc: <COLLINS@xxxxxxxxxxxxx>
Sent: Sunday, June 24, 2007 11:44 AM
Subject: {Collins} Re: Speaker Wire Short on an A-4


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> Just saw the threads.
>
> Bob Young is right.  It IS better to short out the speaker terminals
> than to leave it open.  The output transformer has been known to short
> when left with NO load BUT ONLY ON TUBE amps with output transformers.
>
> Transistor and all solid state units don't even short them for a
> MICROSECOND, they will destroy themselves.   SO NO LOAD ON SOLID STATE.
>
> Bob  W5EUQ
>
> Bob Young wrote:
>> It is better to short out speaker terminals with a tube amp than to leave 
>> it
>> open. There should be no damage especially with a relatively low power 
>> amp
>> like in a radio. I did that countless times when I was a kid with no
>> problems. Many high power tube amps such as guitar or bass amps have
>> shorting output jacks in case someone forgets to plug in a speaker, they
>> will not protect them for a long period of time but it is better than
>> running them open which will destroy a tube amp in short order.
>>
>> Bob Young
>> KB1OKL
>>
>>
>>
>>> From: Glen Zook <gzook@xxxxxxxxx>
>>> Reply-To: gzook@xxxxxxxxx
>>> To: steveclark@xxxxxxxxxxxxx, COLLINS@xxxxxxxxxxxxx
>>> Subject: {Collins} Re: Speaker Wire Short on an A-4
>>> Date: Sun, 24 Jun 2007 08:02:42 -0700 (PDT)
>>>
>>> The audio output transformer is the only thing that
>>> may have been damaged.  However, since the radio works
>>> fine after removing the short there was probably no
>>> damage at all to the 75A4.  Those "olde tyme"
>>> transformers are pretty rugged!
>>>
>>> Glen, K9STH
>>>
>>>
>>> --- Steve Clark <steveclark@xxxxxxxxxxxxx> wrote:
>>>
>>> I temporarily connected a 270G-3 speaker to my 75A-4
>>> using stranded speaker wire failing to use a proper
>>> connectors (I know, haste makes waste). I have used
>>> the radio to great success except for the other night
>>> when I noticed the speaker volume was extremely low.
>>> I assumed an audio tube was going south, but then
>>> checked the speaker wire connection on the radio. Sure
>>> enough, the several strands of speaker wire from one
>>> connection were touching the speaker wire on the other
>>> connection.  I have since corrected this with proper
>>> wire terminals. My question: Did any components in my
>>> receiver potentially suffer damage?
>>>
>>> Everything is working well - I know these tube units
>>> are built like tanks unlike transister based units,
>>> however I need to know if anything should be
>>> checked/replaced to preclude glitches down the road.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Glen, K9STH
>>>
>>> Website:  http://k9sth.com
>>>
>>>
>>>
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