[Amps] 572B - News?

[Carl]

RF Parts will be taking new 572B orders in Jan 2015, Id rather wait than 
hack up a perfectly good amp for an inferior tube.
http://www.rfparts.com/tubes/tubes-572b.html

Carl
KM1H



----- Original Message ----- 
From: "Marcelo Cabral" <py1kr.marcelo at gmail.com>
To: <amps at contesting.com>
Sent: Friday, November 07, 2014 10:46 AM
Subject: Re: [Amps] 572B - News?


> Hi, Gustavo!
>
> Thanks for the tip, despite I'm thinking in avoid a big mod for the amp 
> because I'm building my home tower (60 ft), assembling one amplifier 
> running 2 x GU43B, and restoring an old Brazilian made Rig... I'm starting 
> to convince the mod will be the best way.
>
> 73,
> Marcelo - PY1KR.
>
>
> -----Original Message-----
> From: Gustavo V [mailto:lu6avm at gmail.com]
> Sent: sexta-feira, 7 de novembro de 2014 13:06
> To: Marcelo Cabral
> Subject: Re: [Amps] 572B - News?
>
> Hola Marcelo.
>
> you can modified your amp to use 2x Gi7BT russian tubes, just buy from 
> http://UR4LL.net  Dr Alex is a nice person and sell original SOVIET tubes 
> :)
>
> I'm building one right now and I got several matched tubes (same lote)
>
> your modifications will be really few, your HV PS give you the correct 
> voltage (2400V) that are ok for Gi7Bt, maybe have to modified/change the 
> filament one...
>
>
>
>
> 73's
> Gustavo
> LU6AVM
>
>
> On Fri, Nov 7, 2014 at 4:31 AM, Marcelo Cabral <py1kr.marcelo at gmail.com> 
> wrote:
>> Hi, all!
>>
>> I'm Marcelo, from Brazil, my call is PY1KR. This is my first message
>> for the group and I like DX and Electronics issues.
>>
>> I have a small Yaesu 2100Z and last week one of the "Taylor" (RF
>> parts) 572B starts to present a weak blue glow, the Idle current of
>> the amp was increased and this same tube is overheating. I've checked
>> Bias, Cathode HV and LV Anode voltages, all appear to be ok.
>>
>> Swapping the tubes position, the problem follow the tube pointing the
>> solution for a new one.
>>
>> Where to find good tubes? Maybe the easy way for get a reliable amp
>> must be swap the glass tubes for ceramic (like GI7B, 3CX)?
>>
>> This MP of 572 was used no more than one year and no more than 60W
>> driven in good SWR antennas (near 500W in continuous carrier). I'm
>> very disappointed, and thinking because of problems like this RFparts
>> stop to sell these Chinese tubes remarked, recently I've change some
>> mails with Terry from RFparts and he don't appear very cheerful about new 
>> tubes...
>>
>>
>> My best regards,
>> Marcelo - PY1KR.
>>
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>
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