[Amps] doorknob cap suppliers ?

[Robert Harmon]

Carl,

I hear what you are saying on higher voltage caps and yes it is cramped, I checked the available room 
and there really isn't any room for adding much larger caps.  
RF Parts has some ceramic doorknobs in stock that look suitable.  They are 2000pf at 7.5kv and they are about 7/8" in diameter. A pair of these conected in parallel would fit o.k.  

No steel or stainless, I am thinking of using 3/8" wide copper strap for the doorknobs. I would love to find some
silver plated strap like the plate strap is,  but maybe getting too carried away. 


Bob
K6UJ


  


 

  
 
On Mar 18, 2011, at 1:42 PM, Carl wrote:

> I see no reason to go higher voltage in that amp. Similar B+ level products have been using the standard 5KV ceramic doorknob for many decades. The antenna safety chokes are there for a reason and if there is an antenna fault while transmitting saving the 8874's will be your major concern....always monitor the grid current.
> 
> With Russian caps you first need to have the room which is already cramped, and metric brass or screws and washers....you arent going to use steel or stainless are you?
> 
> Carl
> KM1H
> 
> 
> ----- Original Message ----- From: "Robert Harmon" <k6uj at pacbell.net>
> To: <dezrat1242 at yahoo.com>
> Cc: <amps at contesting.com>
> Sent: Tuesday, March 15, 2011 2:47 PM
> Subject: Re: [Amps] doorknob cap suppliers ?
> 
> 
>> 
>> I see your point.  I'll see if I can find higher voltage caps
>> that will fit O.K.
>> I have been looking at the Russian caps on ebay,
>> good prices.
>> 
>> thanks Bill,
>> 
>> Bob
>> K6UJ
>> 
>> 
>> 
>> 
>> On Mar 14, 2011, at 10:51 AM, Bill, W6WRT wrote:
>> 
>>> ORIGINAL MESSAGE:
>>> 
>>> On Sun, 13 Mar 2011 12:00:53 -0700, Robert Harmon <k6uj at pacbell.net>
>>> wrote:
>>> 
>>>> Yes that is what is in there, two 2000pf 6kv discs in parallel.
>>>> I'm going through and upgrading caps in the amp,
>>> 
>>> REPLY:
>>> 
>>> For what it's worth - IMO, 6kV is a little bit marginal. If you ever
>>> have an antenna fault while transmitting (broken wire, shorted coax,
>>> whatever) the voltage across the cap can easily exceed 6kV. As long as
>>> you're upgrading, why not put in a 12 or 15 kV cap? The cost is only a
>>> little more and the peace of mind is priceless.
>>> 
>>> I recommend the Russian doorknobs on eBay. Good stuff.
>>> 
>>> 73, Bill W6WRT
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>> 
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