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[Amps] Fwd: Ten-Tec Titan 425 - input SWR high

Subject: [Amps] Fwd: Ten-Tec Titan 425 - input SWR high
From: Louis Parascondola via Amps <>
Reply-to: Louis Parascondola <>
Date: Sun, 19 Oct 2014 10:15:41 -0400
List-post: <">>

-----Original Message-----
From: Louis Parascondola <>
To: va3uma <>
Sent: Sun, Oct 19, 2014 8:15 am
Subject: Re: [Amps] Ten-Tec Titan 425 - input SWR high

Usually the input swr on those amps are OK.  I have seen some that have issues 
on different bands.  Since the age of the amp is getting up there I would say 
that maybe the mica caps have drifted off value.  They are cheap enough to buy 
and may want to consider changing out those on the bands that are bad.  I never 
saw one of those amps that had bad input swr on every band.  If it was bad in 
every bad, I would suspect  something else maybe, try a different length patch 
cord first, make sure it is a good patch cord.  Also, if one tube is weak that 
could cause an input imbalance.  The amp is capable of way over 1500 watts 
output so to say it does 1500w output does not qualify the tubes as good.  Mind 
you, one tube with low emission could throw things off.  The key here is that 
if every band is bad I would suspect a universal problem.  My first plan would 
be to try a different set of tubes before I did anything else besides change 
the input patch cord to eliminate that as being p
 roblematic.  ALWAYS explore the simple things first, then go to the more 
drastic measures.  I just worked on my friends 425 and he has a problem with 
input swr on one band but the rest are fine.  His amp can be easily driven to 
over 2KW+

-----Original Message-----
From: Prem <>
To: amps <>
Sent: Sun, Oct 19, 2014 8:03 am
Subject: [Amps] Ten-Tec Titan 425 - input SWR high

Friends, for a long time now, the input SWR on my friend's Ten-Tec Titan
425 is very high (average > 2 on all bands) - when measured with a MFJ
analy at the input - with a 50R dummy-load at the AMP output.

So long, he's used an ATU between the exciter and the 425, but I'd like to
find out if there's way to fix this SWR problem (no slug-tuning. fixed L
and C in the i/p LPF).

I've already checked/assessed the following:
1- Amp gives full o/p of 1500W pep on a DL with an ATU between the exciter
and the amp (so, tubes should be OK ?)
2 - The vacuum relay contacts test 100% OK with a multi-meter continuity
3 - No visual or smell indication of any burns/arcing/toast - in the I/P
LPF or in any other circuit elements.
4 - Band switch contacts look good. Cleaned with De-Oxit - just to be on
the safer side.
5 - Ig and Ip are as per specs

Any help/lead is appreciated.

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