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Re: [Amps] Commander 2500 toroid

To: <>, "'Amps Group'" <>
Subject: Re: [Amps] Commander 2500 toroid
From: <>
Date: Sat, 20 Aug 2022 18:08:21 -0400
List-post: <>
I have several spares of those cores.  They are micrometals T225-2b cores.  And 
yes, overheating can crack the cores, at least a couple that I deconstructed 
showed a hot spot and obvious crack.  The basic problem with the way that 
toroid is used is that the unused coils are shorted by the band switch, so when 
you are on 40m both the 80m and 160m sections are shorted, on 80m the half of 
the coils for 160m are shorted.  This causes rapid heating from the high 
circulating currents and in worst case scenarios the delryn (sp?) support melts 
and can catch fire, as can the plate choke that is just above the toroid.  For 
use on 40m-10m rtty I modified one so it didn't have 80m/160m sections.  For 
80m I made one of them into a single band amp by removing the high band coils 
and mounting two toroids in series on top of the rf deck instead of hidden 
under the caps where there is very little air flow.    Search for 'hf2500' on 
this page for more fun stuff about that amp:

David Robbins K1TTT
AR-Cluster node: telnet://

-----Original Message-----
From: Amps <> On Behalf Of gudguyham--- via Amps
Sent: Saturday, August 20, 2022 16:49
To: Amps Group <>
Subject: [Amps] Commander 2500 toroid

Folks, I’m in need of a Command Tech HF2500 low band toroid.  Looks like FT8 
got the best of this one.  If anyone has one, knows who does, or can rewind one 
please let me know.  There’s a remote possibility if I take it out I can 
possibly try to wind one but this thing got so hot it melted the (Teflon?) 
jacket right off the wire.  Question is, does the heat destroy the iron core?  
Any help appreciated.  Thanks, Lou

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