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Re: [Amps] B&W PT2500

To: <>, "'Bob Gibson'" <>, <>
Subject: Re: [Amps] B&W PT2500
From: <>
Date: Fri, 26 Aug 2022 23:47:03 -0500
List-post: <>
For an input SWR when using a solid state amplifier against a PT2500 Amplifier, 
why not use something like this?  It will provide a 50hom load to the 
transceiver input  regardless of the band exercised.  They offer 1db, 2db on up 
of attenuation, and are matched at 50ohms to the Transceiver input of the amp 
all the way to 1Ghz or better. The point being here the transceiver will always 
see a ~50ohm load.  Just a thought. 

Thank you,


-----Original Message-----
From: Amps <> On Behalf Of gudguyham--- via Amps
Sent: Thursday, August 25, 2022 11:48 PM
To: Bob Gibson <>;
Subject: Re: [Amps] B&W PT2500

Bob, I’ve got two of these amps in my shop now.  You should be aware that the 
stock open frame relay is 120vdc and most radios can’t handle this switching 
voltage/current.  You’ll need a buffer of some sort.  Personally I like 
installing a soft key internally.  You can use a Harbach SB220 soft key kit or 
a similar one completely assembled.  I have completely assembled soft key 
units.  Don’t try to key this amp without one!  Also, be aware that this amp 
does not have adjustable input networks like many other amps do.  Keep in mind 
that these amps were designed around being used with tube type radios with 
adjustable pi-networks.  Therefore the input networks only needed to be “good” 
as to present an “ok” swr to a tube exciter.  Using this amp with a solid state 
radio you may find that the input swr is less than stellar.  If it’s a bit high 
for a solid state radio they will fold back and your power output will be low.  
Check your input swr!  If it’s poor there’s not much you can do about it except 
use the radio tuner.  The input circuits are buried and inaccessible.   Way 
before it’s time, this amp has a grid trip circuit which is factory set for 
400ma.  Lou

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On Thursday, August 25, 2022, 11:38 PM, Bob Gibson via Amps 
<> wrote:

I have bought a B&W PT2500 amplifier and I looking for blower for the unit. If 
anyone happens to have a part number or where to find one..Please let me 
know..Also has anyone done any kind of a mods to one..20 meter output is low.. 

   73s Bob W5RG
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