[Amps] B&W PT-2500A HF Amplifier

[Carl]

Ummm, I never said that B&W used a different switch or transformer. AFIK, 
they could have used a US built transformer but I never asked, even when I 
was at the factory.

As far as the Pi-L, I beg to differ as it was a severe problem that went 
thru 2 revisions in the US before it was stable on all bands and under all 
possible conditions such as all out contesting for 48 hours non stop.  A new 
parasitic suppressor design was also implemented.

If you read the thread you will see that I was comparing the final version 
B&W amp to other 2 x 3-500 amps on the market and concluded it was the best 
of the breed. Viewstar deserves a good part of the credit.

Carl
KM1H




----- Original Message ----- 
From: "Dwayne" <863 at telus.net>
To: <amps at contesting.com>
Sent: Wednesday, March 24, 2010 5:48 PM
Subject: Re: [Amps] B&W PT-2500A HF Amplifier


>
> ----- Original Message ----- 
> From: "Carl" <km1h at jeremy.mv.com>
> To: "Zeitler, Lane LT, FST-1" <zeitlel at cpr3.navy.mil>; 
> <Amps at contesting.com>
> Sent: Tuesday, March 23, 2010 4:14 PM
> Subject: Re: [Amps] B&W PT-2500A HF Amplifier
> Carl....
>  The PT-2500a   Viewstar  Always had the Mod #86 band switch.. I've had a
> number of these amps here and that band switch was common befors B&W ever
> got it... As well the pi-L tank circuit was never a problem..  What was a
> problem was that Potter es Brumfield relay timing..  I still have two of
> these amps and the only mod I've done is a QSK circuit for c.w.  Oh and 
> the
> changes B&W made had nothing to do with inproveing  the amp. like the"
> transformer" change..
>       Dwayne   Ve6qx
>
>> Yep, Ive seen those in person. The B&W used a massive RSC (now Multi Tech
>> Industries) Model 86 switch, chimneys, and a healthy transformer.
>> 160-10M and 1800-2000W out on all bands. I sold about 20-25 as a
>> distributor
>> and had a pair of very early models that I did the redesign work on as
>> loaners for a few years of contesting.
>>
>> There is also the Yokagawa P9306 industrial amp that many have converted.
>>
>> Carl
>> KM1H
>>
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Zeitler, Lane LT, FST-1" <zeitlel at cpr3.navy.mil>
>> To: "Carl" <km1h at jeremy.mv.com>; <Gary at ka1j.com>; <Amps at contesting.com>
>> Sent: Tuesday, March 23, 2010 7:04 PM
>> Subject: RE: [Amps] B&W PT-2500A HF Amplifier
>>
>>
>> Sigma made a 3-500Z amp in the late 70's/early 80's that was very well
>> done. They apparently did not import many to the states b/c you rarely
>> see them for sale. I had one about 15 yrs ago, the weak link was the
>> bandswitch. It was also an absolute nightmare to service.
>>
>> Tokyo-Hy Power used to make a "HL2K" that ran a pair of 3-500Zs. It too
>> was very well done. Not very easy to service either.
>>
>> Lane
>> Ku7i
>>
>> -----Original Message-----
>> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
>> On Behalf Of Carl
>> Sent: Tuesday, March 23, 2010 12:08 PM
>> To: Gary at ka1j.com; Amps at contesting.com
>> Subject: Re: [Amps] B&W PT-2500A HF Amplifier
>>
>> Viewstar was Hammond and since they couldnt crack the US market they
>> approached B&W.
>>
>> The Pi-L tank had a few problems causing lots of smoke and that was
>> redone.
>> Its the best of the 3-500 amps but its high price limited sales and it
>> was
>> discontinued.
>>
>> Carl
>> KM1H
>>
>>
>>> Tony,
>>>
>>> I gave my Dad what I believe was the original version of that Amp,
>>> the Viewstar PT-2500A made in Scarsborough, Ontario. He uses it
>>> daily. I've been so wrong before but I think B&W bought the amp
>>> design from Viewstar.
>>>
>>> If you can scan those pages I'd like a copy of them myself.
>>>
>>> Thanks,
>>>
>>> Gary
>>> KA1j
>>>
>>>> Cleaning out here and came across the "73 Magazine" review of the
>> above
>>>> amplifier (3 pages).  If you have this amp and would like this
>> original
>>>> copy review, I'll be happy to send it along to you.
>>>> 73
>>>> Tony, W4FOA
>>>>
>>>>
>>>> Watch your thoughts; they become words.
>>>> Watch your words; they become actions.
>>>> Watch your actions; they become habits.
>>>> Watch your habits; they become character.
>>>> Watch your character; it becomes your destiny.
>>>>
>>>>                             -Frank Outlaw
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>>>
>>>
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