[Boatanchors] [Johnson] Valiant 6146 Question

[WQ9E at btsnetworks.net]

I have two Valiant 1 transmitters and a Valiant 2.  I don't mix types in the final or modulator but both originals have 6146B tubes in the final and the Valiant II is running  the W version.  I know at least one is running W variants in the modulator but I cannot recall what the others are using.  I have had zero issues with B or W version tubes in any of my Johnson, Heath, or B&W gear.

I did run into an issue with a group of W series tubes I got from Fair flashing over at initial power up.  That was over 10 years ago and Fair replaced the entire group (I bought 20 of them).  I recall at the time that there was an issue with some of the GE production runs being bad and my group came from one of those.  I tested all of the replacements in a SB-102 (where the issue first showed up) and all the replacement group was fine.  So if you do get a flash over in a W it could well be the tube and not the gear at fault but not because of the suffix variant.

The only amateur gear I have run across that has a problem using the B (or late version W which is equivalent to a B) is my Collins KWM-2 which I updated, per Collins notes, so that it also works properly with later 6146 variants.  

I attribute the Collins issue to a design shortcoming and not a tube issue, the neutralizing circuit was marginal even for the original version 6146 tube.

Rodger WQ9E

-------- Original Message --------
> From: "Carl" <km1h at jeremy.mv.com>
> Sent: Wednesday, December 19, 2012 10:20 AM
> To: whitebear1122 at comcast.net>, <Johnson at mailman.qth.net
> Subject: Re: [Johnson] Valiant 6146 Question
> 
> Ive tried all combinations and as many brands and date codes as I could find 
> in a V II about a year ago out of curiosity. They all worked just fine 
> 160-10M.
> 
> A Valiant will be on the bench early next year and I'll try again.
> 
> Carl
> KM1H
> 
> 
> ----- Original Message ----- 
> From: <whitebear1122 at comcast.net>
> To: <Johnson at mailman.qth.net>
> Cc: <boatanchors at mailman.qth.net>
> Sent: Wednesday, December 19, 2012 10:32 AM
> Subject: [Johnson] Valiant 6146 Question
> 
> 
> >
> >
> >
> > While I've read Glen Zooks 6146 article, and fine article it is too!, I 
> > wonder if anyone here has had any personal expereince with 6146 vs 6146B 
> > vs 6146W mixing and matching in the PA of the Valiant. Over the weekend I 
> > repaired my Valiant and ended up replacing two of the three 6146's in the 
> > PA. They only blew out after I had overstressed the transmitter while 
> > trying to tune up on 160m with an antenna and tuner that just wasn't going 
> > to take me there, so it wasn't the transmitters fault nor the tubes fault. 
> > I was my error. I've since replaced the antenna and it tunes fine on 160m 
> > now. After I closed up the transmitter,I then remembered the 6146 mixing 
> > and matching debate. I had not paid any attention to the 6146 flavors when 
> > put in the replacements. It seems to be working nicely at least on 80m and 
> > 40m. Haven't tried it on 20m yet. 150 watts output on CW. I know I have 
> > 6146W's in the modulator and they work FB.
> >
> >
> >
> > I was just curious if others had actually had problems with the mixing and 
> > matching 6146's in the PA.
> >
> >
> >
> > I am also looking to buy some NOS 6146s, either straight, A's, B's, or 
> > W's. I need some spares now. Out of my 4 spares, two are now in the 
> > Valiant, and the other two turned out to be weak. They read 45 on the TV-7 
> > (where 35 is minimum), but then quickly started dropping to the 20's 
> > before I let off on the button.
> >
> >
> >
> > Thanks. 73, Scott WA9WFA
> > ______________________________________________________________
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