[Amps] more questions..

R.Measures r at somis.org
Sat Dec 11 04:40:06 EST 2004 

On Dec 10, 2004, at 9:07 PM, Dan wrote:

> Little mor eupdate..
> i was wrong about hte transfomer taps the newer amp (the one I just 
> got) is wired for the factory 120 volts default and I get 1600 volts 
> the amp that I get more power out of is wired for 100 volts at the 
> transformer and gives me 1850 to 1900 volts. Could this be the 
> difference in output or the blackened tube?? I still wonder what 
> trouble i get into by swapping out the 811a between the two. actuall I 
> believe the older amp wired for 100 volts abd giving me 1900 volts 
> might actually be the one that should be changed to prevent early 
> death to the tubes.. manual says nominal 1700 volts///
The dead tubes I saw in an AL-811 were not offed by exceeding the 1500v 
rating of 811As.  Excessive anode-V and AØ tends to melt holes in the 
811A's puny 65w anodes  Instead, these tubes died from broken filament 
wires - even though the amplifier was not dropped.  The amplifier in 
question had been operating normally for about a half-hour when a pop 
was heard and the filaments went dark.

> anyway you guys are the experts most concerned abott he startup spark, 
> large power surge  and smell but might that be due to sitting 2 
> yrs..It rusn fine now and seems to have power out but bot as much as 
> the other older amp
>
>
> any and all ideas are appreciated.. thanks
> Dan
> ----------------
>
> Well I received the amp looks really clean inside and out.. checked it 
> all out very close.. one of the tbes appears to be blackened in the 
> lower glass at one spot above the base. Does that mean anythign 
> important at this stage.
>
> second question.. I decided to do the quick switch on and off to see 
> what happens.. man that was exciting.. flip switch on and amp lights 
> came on kinda loud spark and smell of sometign burit. also it took 
> such a chunk of power it rebooted my computers on the sam eline.. 
> swichted it all off pulled plug took case off again.. did not see 
> anythign that might indicate anythign burnt etc.. still looks clean..
> sooo being a brut for punishment I put the case back on and hit the 
> switch again. this time all seemed ok.. at least for about 10 secs 
> then a small pop and i  could see a little arc at the vents near the 4 
> tubes. switched it off.. seemed ok so switched it back on (I know I 
> know).. anyway this time all was fine.. had on abt 1 hr no problems  
> voltage reads a little lower then my other 811H on same line this one 
> reads 1600 and the other reads 1800.. seems tapped same way..
>
> anyway decide to try a small load into it works fine at least it 
> appears to.. now more questions.. It appears on the same exciter and 
> antenna I can not get quite the output that the other  811H gets.. 
> where on the other I get 600 + on 20 meter with little drive seems 
> this only want to do about 450 or so.. can that be an indication that 
> the blackened tube is bad??
>
> one more questions since I have the other 811H what problems would I 
> be causing if I swapped the 4 tubes form the other amp to this one? I 
> thought that may tell me if a new set of tubes woudl help twiththe  
> output of this amp.
>
> Also.. any ideas about the start up problems sta6ed above?? it is 
> runngin right now stil showing only about 1600 volts but I have tested 
> it on 3 bands seems just fine just a little lacking in power output..
> thanks for any suggestions.. I woud like ot hear opinions about 
> swapping the 4 811A form the know good amp to ths one for a est..
> thanks
>
> *********** REPLY SEPARATOR  ***********
>
> On 12/07/2004 at 10:06 PM Pat Poirier wrote:
>
>> Hi Dan,
>>
>> If your amplifier that has been stored is only two years old, it 
>> shouldn't
>> be a big deal to turn it on and just let it idle for several hours. 
>> If the
>> amplifier was manufactured more than 5 years ago, I would use a 
>> variable
>> AC
>> voltage transformer to bring the power up from low voltage to full 
>> voltage
>> over a short time.
>>
>> I would first start out by inspecting the power supply and making sure
>> that
>> there is nothing leaking or growing out of the electrolytics. If 
>> there is
>> nothing and the amplifier isn't that old, I would turn it on and then 
>> give
>> the tubes several hours just idling with no RF power to make sure that
>> they
>> are burned in and that they are not gassy. Then you should be all set 
>> to
>> power it up.
>>
>> 73,
>>
>> Pat W1KA
>> ----- Original Message -----
>> From: "Dan" <dpipes at earthlink.net>
>> To: <Amps at contesting.com>
>> Sent: Tuesday, December 07, 2004 9:27 PM
>> Subject: Re[2]: [Amps] 811A - Tubes
>>
>>
>> Pat,
>> Thanks for the info.  now you bring up another question. I have bought
>> another 811H thathas been stored for abotu  2 years. stored in a  a 
>> clean
>> dry closet inside plastic bags etc so it is very very clean.
>> might be a stupid question but... is there anythign i shold do or 
>> maybe
>> NOT
>> do when I first fire it back up? Can sitting there for two years 
>> actually
>> hurt the amp? i woudl think that some  store stock could get stored 
>> that
>> long or maybe warehouse stock..
>>
>> Just curious this list has smoe real experts ,g. and I just do nto 
>> want to
>> screw up a perfectly good amp  by bringing it out of storage and maybe
>> doing
>> somethign wrong on re-start
>> thanks
>> Dan
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 12/07/2004 at 8:41 PM Pat Poirier wrote:
>>
>>> Hi Dan,
>>>
>>> Don't bother spending the extra money on the Svetlana 811's. I had 
>>> four of
>>> the white ceramic base Svetlana tubes in my AL-811H.
>>>
>>> I purchased a matched quad from RF Parts of their Taylor Brand 
>>> 811A's and
>>> they were the same output that my Svetlana tubes were.
>>>
>>> My AL-811H is used as a back up to my backup amplifiers and it is 
>>> very
>>> seldom ever used except to turn it on for an hour or two idling to 
>>> keep
>>> the
>>> electrolytics formed every six months.
>>>
>>> For $77.20 from RF Parts I don't think you can go wrong. Don't bother
>>> looking at 572B's you will not see any more power and they are 2 1/2 
>>> times
>>> the price.
>>>
>>> Good Luck,
>>> 73,
>>> Pat W1KA
>>>
>>> ----- Original Message -----
>>> From: "Dan" <dpipes at earthlink.net>
>>> To: <amps at contesting.com>
>>> Sent: Tuesday, December 07, 2004 8:06 PM
>>> Subject: [Amps] 811A - Tubes
>>>
>>>
>>> I need 4 811 A tubes for my Ameritron 811H. I have read some say th
>>> Russain
>>> tubes are best some the centron etc.. What are the opinions and 
>>> where is
>>> the
>>> best place to buy a set of 4...
>>> Thanks
>>> Dan
>>>
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>>
>>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org

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